Water Heating


Last updated April 30, 2017

 

 

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Background | Conventional Electric | Solar Photovoltaic with Conventional Electric | On-demand (tankless) | Electric heat pump | Solar thermal | And the winner is... | Roof work | Installation | Journal | Money saved | Actual Payback


On November and December 2010, Norma and I had photovoltaic solar panels installed. See Solar Energy. This worked out extremely well and reduced our electric bill in the amount that was predicted. If I had to do things all over again, I would definitely choose solar again.

In 2013, I had my chance. But this time, it was for hot water heating. Our hot water heater had been leaking very slowly over the last couple years. At first I thought it was just condensation. But it got worse and worse over time.

Our system prior to June 2013 was a 60 gallon electric hot water heater. The yellow energy guide sticker says it uses 4959 kilowatt hours (kwh) per year. As of May 2013, we pay $0.1287 per kwh using Castlebridge Energy Group as our provider (this includes charges, fees, and taxes). This means that we have been paying about $638.22 per year in electric bills for our old hot water heater. The exact number is probably much smaller since there are just 2 of us in the house but for lack of better data, I'm going with the energy guide sticker estimate.

We don't know exactly when it was installed but the energy guide sticker quotes energy prices based on 1994. Yes, 1994! It has lasted at least 19 years! Amazing.

Harnessing the sun's energy for heating hot water is something I've considered for awhile. See solar hot water heating. But first I wanted to explore all my options.

I found the following resources helpful:
  • American Council for an Energy-Efficient Company (ACEEE) - Water Heating: This has some good information but I found their "installed cost" column to be off by a factor of about 1.5 to 2.5.
  • California Energy Commission - Consumer Energy Center
  • Department of Energy - Selecting a New Water Heater


  • Conventional Electric

    The first consideration was replacing the existing electric hot water heater with something similar. If nothing else, this would at least give me a baseline to compare with other systems for cost savings.

    According to Department of Energy - Tankless or Demand-Type Water Heaters, storage water heaters last 10 to 15 years.



    Sanford Kramer - AO Smith

    William C. from Sanford Kramer came by on April 4, 2013 to give me a price quote. For $2141, they would do the following:
  • Remove the old hot water heater.
  • Install a new 50 gallon AO Smith hot water heater with a 6 year warranty. I didn't like their website because they didn't give me the estimated number of kWh of electricity consumed by their hot water heaters. Instead, they gave an estimated annual operating cost which would vary depending on electric costs.
  • Purchase and install an expansion tank. This is synonymous to a surge protector in that it protects against system fluctuations. It is a code requirement but wasn't when my hot water heater was originally installed.
  • Purchase and install an emergency shut off valve.

  • For the remainder of this web page, assume all final costs include removal of the old hot water heater, the expansion tank, and all installation costs unless otherwise stated.

    This price quote cost me $29. I asked about other systems and William said he would get back to me about this but never did.



    Arundel Cooling and Heating - Marathon 50

    I asked John of Arundel Cooling and Heating about the $899 Marathon 50 gallon lifetime electric hot water heater which has an estimated yearly electric use of 4671 kwh which is fairly low for a conventional electric system. Based on our energy cost, we would pay $601.16 per year to run the Marathon 50 system. Marathon water heaters are made by Rheem. John was my salesman for the geothermal heat pump I had installed in 2012. Arundel has an A+ rating with the Better Business Bureau (BBB). On April 4, 2012, he gave me a quote for $2998 which includes a similar service to that offered by Sanford Kramer. I expect the price now would be a little higher since at the time, the system was selling for $754. After 10 years, the cost of the Marathon 50 system plus its energy costs comes to $2998 + (10 * $601.16) = $9009.60.



    Financial Incentives

    There are no financial incentives to conventional electric storage hot water heaters.


    Solar Photovoltaic with Conventional Electric

    One of the reasons I was considering getting a conventional electric system is because I wanted to know if such a system with additional solar photovoltaic panels to power it would be cheaper than other alternatives. I contacted Brent of Solar Energy World for a quote for more solar photovoltaic panels. His company installed panels for me in 2010 and did a very good job. See Solar Energy.

    For $10,140, I could get 10 Suniva Optimus 260 Monocrystalline Solar Module (OPT260-60-4-1B0) panels that would provide me about 3131 kwh of electricity per year. This would pay for 67% of the electricity needed for the hot water heater. This means that having a Marathon 50 hot water heater with 10 Suniva 260 photovoltaic solar panels to offset the cost of electricity would cost me $198.38 per year. But the up-front cost would be $10,140 + 2998 = $13,138.



    Financial Incentives and Payback

    How would this work out in the long run? To answer that, we need to consider the financial incentives:
  • 30% federal tax credit: $3042
  • Maryland state energy grant: $0. This would have been $1000 but as of 2013, I am no longer eligible because I obtained grant money for the panels on my garage.
  • Solar renewable energy credits (SRECs): $348.10 annually; this assumes $112.29 per SREC which is based on the average value for which I sold SRECs generated from December 7, 2010 to August 29, 2013. But this is an optimistic value since SRECs typically decrease in value over time.

  • This means the net cost for the Marathon 50 hot water heater with 10 Suniva 260 photovoltaic solar panels after 10 years is $13,138 - ($3042 + (10 * $348.10)) = $6615 if we assume SRECs maintain their value. If they become worthless, then the net cost is $13,138 - $3042 = $10,096. Realistically, the actual net cost is between the two and closer to the lower amount.

    After 10 years, the net cost of the Marathon 50 system with 10 Suniva 260 solar photovoltaic panels plus its energy costs comes to $6615 + (10 * 198.38) = $8598.80 if SRECs maintain their 2010-2013 value. If SRECs lose all their value, then the net cost is $10,096 + (10 * 198.38) = $12,079.80. Realistically, it is between the two and closer to the lower amount.


    On-demand (tankless)
    Another option I wanted to consider was the gas on-demand (tankless) system. We don't have a natural gas line running to the house. According to oil versus natural gas, getting one would cost at least $740 as of April 14, 2011.

    Such a system uses natural gas to heat water when it is needed. This means that no tank is used to store hot water. It is extremely efficient but has a few drawbacks, depending on who you ask. In the house that Norma lived in back in 2008, there was an on-demand gas hot water heater. I found it difficult to get the water comfortably warm. It was a little loud too but it was also on the main floor right next to the kitchen. A neighbor of mine who had such a system installed in 2013 says it takes longer to get hot water to their upstairs shower. I think advances have been made since 2008 and the current drawbacks are negligible compare to the advantages. Having a large house isn't an obstacle either, though it might have been in the past.

    I did hear bad things about gas on-demand systems from William C. from Sanford Kramer. He mentioned that they were having problems with the manufacturer standing behind their product but I don't remember who the manufacturer was. I haven't heard any similar issues from anyone else.

    According to Department of Energy - Tankless or Demand-Type Water Heaters, most tankless water heaters have a life expectancy of more than 20 years. They also have easily replaceable parts that extend their life by many more years.

    The United States has been called the Saudi Arabia of natural gas, meaning that we have more than our fair share. So that must mean it is cheap, right? In some ways, yes. But while the U.S. has more than its share, Uncle Sam is also taking more than his share.

    As of March 2013, one therm of gas purchased from Castlebridge costs $0.51. So for 71 therms, you pay $35.70. But the surprising thing is that you pay $35.24 for the delivery of this gas. This includes a constant customer charge of $13 that is there whether or not you use any gas. Other charges include the EmPower Maryland charge, distribution charge, and franchise tax. These are all based on the number of therms used.

    For electricity, there is also a constant customer charge but that is $7.50. If you use 1345 kWh of electricity at a rate of $0.0779 through Castlebridge, then you pay $104.78 for electricity and $56.36 for the EmPower Maryland charge, distribution charge, and other charges, fees, and taxes.

    These above charges are taken from a statement at my rental townhouse in Hanover, Maryland because Norma and I don't use gas.

    For gas, $35.24/($35.70 + $35.24) = 49.67% of what you pay goes to pay for charges, taxes, and fees. Compare this with electricity which is only $56.36/($104.78 + $56.36) = 21.87%. Of course these values will differ based on how much gas and electricity you use. In the end, you might argue that all that matters is how much you pay and it doesn't matter who gets what. But at the same time, I'd like to know how much of my money is actually going towards paying for what I want.

    Our country may be blessed with a lot of natural gas, and maybe it is cheap, but when you pay as much in charges, taxes, and fees, is it still cheap?



    Love's Heating and Air - Bosch 980

    I spoke to Merle at Love's Heating and Air. I contacted him when I was looking for a geothermal heat pump. His company has an A+ rating with the BBB. While I didn't choose his company to do business, I was impressed with his knowledge and the experience of his company. So I decided to talk to him again.

    Merle quoted me $3680 for a Bosch 980 on-demand gas hot water heater. This assumes I pay to have the gas line run to the house.

    I wasn't able to find any information about the Bosch 980. I also had a hard time finding any information about how much an on-demand gas hot water heater would save me in energy costs. Some manufacturers made claims as to how much their system "could" save me but I wanted a more unbiased report such as the yellow energy guide sticker. Unfortunately, such information is not available for on-demand systems.

    I did, however, find useful information at American Council for an Energy-Efficient Company (ACEEE) - Water Heating. While this website makes very inaccurate claims for installation costs (for the Baltimore/Washington D.C. area, at least), they do put things in perspective. Using this data, I conclude that energy costs for a typical on-demand gas hot water heater will be 58% as compared to high efficiency electric storage. I assume this includes taxes and fees but I really don't know for sure. This means that if we assume the Marathon 50 is a high efficiency electric storage system, then the annual energy cost for a typical on-demand gas hot water heater will be about 0.58 * $601.16 = $348.67.



    Arundel Cooling and Heating

    Arundel Cooling and Heating also does on-demand gas hot water heater installation but I didn't get a quote from them. No particular reason...it just slipped my mind.



    On-Demand Electric

    There are also on-demand electric hot water heaters. But I have heard nothing good about these. They use a lot of energy and if you want to save money, this is not the way to go. For more information, see Why aren't electric storage tank and electric tankless water heaters able to earn the Energy Star?. I'm thinking system like this are more for mobile homes or other very small units without gas lines.



    Financial Incentives and Payback

    There is one HUGE financial incentives for gas on-demand hot water heaters as of 2013:
  • BGE Smart Energy Savers Program: Up to 50% of improvement cost, $2000 maximum. This means $3680/2 = $1840.

  • This means the net cost for the Bosch 980 hot water heater with the cost of having a gas line run to the house is at least $3680 - $1840 + $740 = $2580.

    After 10 years, the cost of the Bosch 980 hot water heater and gas line installation plus energy costs comes to $2580 + (10 * $348.67) = $6066.70.


    Electric Heat Pump
    A relatively new technology is the electric heat pump hot water heater. This uses thermodynamics to transfer heat and cold in the same way a heat pump works to heat and cool a house. Heat pumps are incredibly efficient so I decided to look into this more.

    These systems are typically called "hybrid" systems because they run in heat pump mode when they can and otherwise, they operate like a regular electric hot water heater.

    I've always known solar thermal systems to be extremely efficient. But after reading Green Building Advisor - Solar Thermal is Dead, I was starting to think it had become obsolete when compared to electric heat pump hot water heaters. The latter is much cheaper and only slightly less efficient. So it would pay for itself much faster.

    I found a good bit of information about the heat pump hot water heaters.
  • Energy Star - Water Heater, Heat Pump
  • Department of Energy - Heat Pump Water Heaters
  • Green Building Advisor - Get Ready for Heat Pump Water Heaters
  • Green Building Advisor - Heat Pump Water Heaters Come of Age
  • General Electric (GE) - Frequently Asked Questions

  • Not all the information on the web about heat pump hot water heaters was positive.
  • Treehugger - A Heat Pump for your Hot Water Heater: Hot or Not?

  • The two big companies that make heat pump hot water heaters are Rheem and General Electric.
  • General Electric - GeoSpring Hybrid Electric Heat Pump Hot Water Heater: On March 26, 2013, Arundel Heating and Cooling gave me a quote for $3932 to remove my old hot water heater and install this one. A pump would also be included to remove condensation to the outside of the house since I do not have a place for water to drain in my boiler room (which is where the hot water heater would go).
  • Rheem - Prestige Series Hybrid Heat Pump Hot Water Heater: On March 15, 2013, Clifton R. of Baltimore Gas and Electric (BGE) Home gave me a quote of $2290 to remove my old hot water heater and install this one. This does not include a pump though I know one could be added for an addtional charge. Also, I don't know if this includes an expansion tank. While the Rheem is much less expensive than the GeoSpring, I had read a few things on-line indicating that the GeoSpring was easier and cheaper to maintain and service.

  • There are other companies that make heat pump hot water heaters such as Kenmore and Stiebel Eltron but I found these to be similar to the General Electric and Rheem heat pump hot water heaters.

    There is one heat pump hot water heater that offers features the others do not. The lesser known but more efficient Airgenerate - AirTap Hybrid ATI66 is hard to find unless you live out west. Compared to other systems, it is much quieter, made of stainless steel so it won't rust out, and operates in heat pump mode when the surrounding air temperature is as low as 20 degrees! All the other systems I found only operate in heat pump mode down to about 40 degrees. On March 26, 2013, Arundel Heating and Cooling gave me a quote for $5579 to remove my old hot water heater and install this one. This includes a pump.

    Some articles have been written to compare different heat pump hot water heaters.
  • Bonneville Power Administration - Field Test of Integrated Heat Pump Water Heaters: There is some good information here but it isn't very readable.

  • After reading quite a bit about heat pump hot waters heaters, I am convinced they are a great piece of technology...but only under certain situations.
    Still, there are some drawbacks to hybrid water heaters. Their fans can be noisy, though owners say they get used to it. Hybrid water heaters are about the same size as a regular electric water heater, but because they need plenty of air for the heat pump, they do best in a space of at least 100 square feet. In hot climates, it's fine to put one indoors in an air-conditioned space because the heat pump puts out cold air as it heats the water -- doing double duty as an air conditioner. For most users, experts say the best location for a hybrid water heater is in an un-air-conditioned space such as a garage, basement or attic -- as long as the temperature there stays above 45 degrees Fahrenheit.
    Consumer Search - Best Heat Pump Water Heaters

    Is a heat pump hot water heater ideal for me?
  • It would go in my boiler room in the basement. There is no floor drain. Therefore, a small pump would need to be installed. Heat pump hot water heaters act as dehumifiers. So that means they generate a lot of condensation. This moisture needs to be removed.
  • A heat pump hot water heater isn't exactly quiet but it wouldn't be any louder than our oil boiler which resides in the same room.
  • Since a heat pump hot water heater relies on thermodynamics to transfer heat and cold, it needs a good bit of space. You can't just put it in a closet and expect it to work fine. But my boiler room is about 600-700 cubic feet and it is ventilated to the outside. This is sufficient.
  • The biggest criticism for heat pump hot water heaters is that since they bring heat to the water and output cold air. This is how heat pumps work. This cold air is output anytime it operates in heat pump mode. From mid-October to May, we probably don't want anything creating cold air in the house. But remember that this system would go in the boiler room which is ventilated with the outside. So it probably won't make the house much colder and even if it does, it will almost entirely affect the basement, which we rarely occupy.
  • Heat pump hot water heaters work best when the air temperature is warm. Most operate in heat pump mode down to about 40 degrees. But this isn't an all or nothing deal. If it is 42 degrees, it might use some heat pump technology and a lot of conventional electric heating. If it is 60 degrees, it will use a lot of heat pump technology and much less (if any) conventional electric heating. I bought a thermal imaging device to measure the temperature of the floor of my boiler room near the hot water heater during the winter. It was 42 degrees on a typical day. So I can't expect much energy savings during the winter.

  • The last 2 reasons are why heat pump hot water heaters are ideal if you live down south. Maryland is not the ideal location unless you have the Airgenerate Airtap system which functions efficiently in much colder climates.

    According to American Council for an Energy-Efficient Company (ACEEE) - Water Heating, I determined that energy costs for a typical heat pump hot water heater will be 43% as compared to high efficiency electric storage. This means that if we assume the Marathon 50 is a high efficiency electric storage system, then the annual energy cost for a typical heat pump hot water heater will be about 0.43 * $601.16 = $258.50. But is this realistic? No claims are made as to location. One might get results like this in Florida but certainly not Maine. According to Consumer Reports - Review of the GE GeoSpring electric heat-pump water heater, tests were done
         in a room with an ambient temperature of 65 to 70F.

    Accorinng to Climate Zone - Climate Information for Baltimore, the average monthly temperatures for Baltimore are as follows:
         Jan: 31.8
         Feb: 34.8
         Mar: 44.1
         Apr: 53.4
         May: 63.4
         Jun: 72.5
         Jul: 77.0
         Aug: 75.6
         Sep: 68.5
         Oct: 56.6
         Nov: 46.8
         Dec: 36.7

    A heat pump hot water heater might run in full heat pump mode 6 months out of the year. During the winter, it would probably run in electric mode all the time. I'll assume heat pump mode 70% of the time and electric mode 30%. So using a typical heat pump hot water heater, my annual energy cost adjusted for Baltimore, Maryland would be more like 0.7 * (0.43 * $601.16) + (0.3 * $601.16) = $361.30. This is 60% of the energy cost as compared to a high efficiency electric storage system which is still pretty good.

    But the Airgenerate Airtap system might indeed meet the 43% expectation since it operates in heat pump mode at such a lower temperature. In this case, my annual energy cost would be 0.43 * $601.16 = $258.50.

    The typical lifespan of a heat pump hot water heater is 13 years, according to DIY Plumbing Advice. This is about the same as a regular electric storage hot water heater.



    Financial Incentives and Payback

    The financial incentives for heat pump hot water heaters are nowhere as good as solar or gas on-demand hot water heaters but there are some.

    Since I only have total installation costs for my situation from Arundel Cooling and Heating, I'm just using their quotes. After 10 years,
  • The cost of the General Electric - GeoSpring Hybrid Electric Heat Pump Hot Water Heater plus energy costs comes to $3932 - $300 + (10 * $361.30) = $7245.
  • The cost of an Airgenerate Airtap heat pump hot water heater plus energy costs comes to $5579 - $300 + (10 * $258.50) = $7864.

  • If you're considering this technology, I highly suggest having someone from BGE Home come out to give you a quote. They charge $50 to send someone out for a pre-inspection. I didn't get this done because I was pretty certain I wouldn't be going this route.


    Solar thermal
    Solar thermal hot water heating has been around a long time and used very successfully, especially in my home state of California. If you want to have the lowest monthly bills possible for hot water heating, then this is the way to go. But you can expect a big up-front cost.

    I did my homework on this subject by reading the following:
  • Proud Green Home - Solar versus Tankless Hot Water Heaters
  • Redwood Coast Energy Authority - Solar Thermal versus Heat Pump
  • Solar Rating and Certification Corporation (SRCC)

  • As with solar photovoltaic panels and opening a business, location is everything. The best location for solar thermal panels is on the south side of my garage roof, which is already occupied with panels. After that, the next best places are the west side of my house roof and the south side of my house roof. The latter is shaded in the morning by our big pine tree. A quantitative answer was determined by using the Solmetric SunEye. This determines solar access based on shading, orientation, and tilt of the roof.
  • The south roof has 85% annual solar access and an azimuth of 160 degrees (180 degrees is due south).
  • The west roof has 89% annual solar access and an azimuth of 248 degrees.

  • If going with solar thermal panels, I would want them on the south roof and reserve the much larger west roof for more photovoltaic panels. This of course would decrease efficiency slightly as compared to the alternative but it will also increase efficiency for my new photovoltaics. Can't have everything.

    According to American Council for an Energy-Efficient Company (ACEEE) - Water Heating, I determined that energy costs for a typical solar thermal hot water heater will be 40% as compared to high efficiency electric storage. Systems such as Schuco make claims closer to 33%. This means that if we assume the Marathon 50 is a high efficiency electric storage system, then the annual energy cost for a typical heat pump hot water heater will be about 0.40 * $601.16 = $240.46. In actuality, I don't know if my savings will be quite this much since the location only has 85% annual solar access. In the worst case, the savings would be 0.85 * ($601.16 - $240.46) = $301.60. This means annual energy costs would be $601.16 - 301.60 = $299.56 which is 50% as compared to high efficiency electric storage. I have heard (but not seen in writing) that savings claims are based on non-ideal situations, meaning that the manufacturer does not actually expect the consumer to have 100% annual solar access. So it is very possible that my savings calculations are a little low.

    Another thing that helps save money in the long run is the life expectancy for a solar thermal system which is over 50% longer than that of a storage tank or heat pump hot water heater system.
    The average life expectancy of qualified solar water heating systems is 20 years, much longer than standard gas or electric storage water heaters.
    - from Energy Star - Solar Hot Water Heaters

    I have been told that once the system has run its life expectancy and is in need of replacement, it will typically only be certain parts that need to be replaced, not the entire system. So for a few hundred dollars (not several thousand), one can make use of solar energy for hot water heating well beyond the lifespan.

    The next step was to get price quotes.



    Solar Energy World

    I contacted Brent of Solar Energy World. Since his company installed my photovoltaic panels and did a good job, I was biased in favor of his company.

    For $9100, I would get the following:
  • Two FKT-1 or FKC-1 Bosch solar thermal flat plate collectors
  • A Bosch SOL-RET80 80 gallon holding tank
  • A 40-60 gallon regular heating storage tank
  • Pump control module, lines, and other materials

  • This system generates 2.5 solar renewable energy credits (SRECs) per year though I don't know if that is only for 100% annual solar access.

    It offsets 3920 kwh of electricity per year as compared to an electric storage hot water heater.

    As much as I would have loved to have gone with Solar Energy World, the fact that their system uses two tanks (one for holding and one for storage), is something I didn't want. My boiler room is also a storage room and I don't want anything taking up more space than necessary in our home which only has 1240 square feet of living space. Norma was pissed enough when some of our closet space was lost to a geothermal return pipe.



    Solar Energy Services

    I found Solar Energy Services via a web search. They met my requirements of being local and having a good rating with the BBB (A+ to be exact).

    Rich S. came out and spoke to me. He convinced me that he is knowledgeable and his company very experienced.

    For $7900, I would get the following:
  • A 4' x 10' Alternate Energy Technologies (AET) model AE40 solar thermal collector. This has a 10 year warranty.
  • An 80 gallon Vaughn Solar Sepco SR Tank with internal heat exchanger, model number S80TSRW20150. This has a 7 year warranty.
  • Pump control module, lines, and other materials

  • This system generates about 2.256 SRECs per year. Unlike solar photovoltaics, this is a set amount and is not dependent on the amount of energy it actually saves me. Someone a lot smarter than me takes all this into consideration and then just assigns a constant value. My understanding is that the system will, on average, save 2256 kWh of electricity as compared to an all electric hot water heater. Dividing this number by 1000 gives the calculated SRECs.

    It has a Solar Energy Factor (SEF) rating of 1.9.

    It offsets 2900 kwh of electricity per year as compared to an electric storage hot water heater. I'm assuming this is as compared to a less efficient hot water heater so I'm going to compare this to my old hot water heater which uses about 4959 kwh per year. This means it will use about 4959 - 2900 = 2059 kwh per year, thereby costing $0.1287 * 2059 = $264.99 in energy costs annually. This is 44% of the energy cost for the Marathon 50 electric storage hot water heater.

    I definitely like this system more than the one by Bosch. It uses a single tank so it takes up about the same amount of space as my current system. It is also American made. Bosch is German.



    Love's Heating and Cooling

    I spoke to Merle at Love's Heating and Air.

    For $7850, I would get the following:
  • Two 4' x 8' Solar Panels Plus flat plate collectors, model SPP Spartan. These have a 10 year warranty.
  • 80 gallon storage tank
  • Temperature controller
  • Pump control module, lines, and other matrials

  • Merle later said he would also give me a 3% discount for recently referring a customer to him.

    Merle wouldn't tell me how many SRECs this system would generate but he said it would be very few. For lack of better information, I'm going to assume 1.5.

    I had a hard time find out the SEF for this system so I contacted Jeff K., the Director of Dealer Development for Solar Panels Plus. He replied with the following:
    Our Spartan and Monarch panels do not have OG300 system certification yet. Our flat panels are made for us by Solar Hot and they have a Solar Energy Factor for a two panel system of 1.2.

    The Spartan is American made.



    Aurora Energy

    I met Michael R. of Aurora Energy at the Howard County Greenfest. We talked for awhile then he came over to tell me about his company. He made a very good impression.

    For $7810, I would get the following:
  • One Velux CLI U12 collector
  • A 65 gallon storage tank
  • System monitor
  • Pump control module, lines, and other materials

  • The written estimate claimed that this system offsets 1430 kwh of electricity per year as compared to an electric storage hot water heater. I'm assuming this is as compared to a less efficient hot water heater so I'm going to compare this to my old hot water heater which uses about 4959 kwh per year. This means it will use about 4959 - 1430 = 3529 kwh per year, thereby costing $0.1287 * 3529 = $454.18 in energy costs annually.

    This system has a SEF rating of 1.7. It was this SEF that he said was much more important than the SRECs when comparing systems. I read up about the SEF and I believe he is right. It seems to be a ratio of how much energy you put into the system and how much you get out of it.

    Velux is not American made in its entirety. I believe it is made in various places but I don't remember where Ryan mentioned. I couldn't find this information on-line.




    Picking a winner

    What is basically came down to was getting the most bang for the buck for a system that fits my need and choosing American made in the event of a near tie.

    Solar Energy World was out of the picture because they use a two tank system and were by far the most expensive. But the other three were all similar in price and all used a single tank system.

    Placing things in order of SEF,
  • The system sold by Love's Heating and Cooling costs $7850 - (0.03 * $7850) = $7614.50 and has an SEF of 1.2.
  • The system sold by Aurora costs $7810 and has an SEF of 1.7. This SEF is 42% higher than the system sold by Love's.
  • The system sold by Solar Energy Services costs $7900 and has an SEF of 1.9. This SEF is 53% higher than the system sold by Love's and 12% higher than the system sold by Aurora.

  • One might assume that if a system is X% more efficient than another system, then it should cost X% more. I suspect that generally won't be the case since costs of things like the pump, lines, and manpower won't be affected by the SEF. But with the costs of all three systems differing by less than 4%, it makes sense that I choose the system that yields a 12-53% higher SEF than the competition.

    Hence, if I go with solar thermal, then I'm choosing Solar Energy Services.



    Financial Incentives

    If I go with Solar Energy Services, I will have a solar thermal system that costs $7900. But this is the up front cost. There are financial incentives for those who are patient:
  • 30% federal tax credit: 0.3 * $7900 = $2370
  • Maryland Energy Administration (MEA) solar energy grant: $500
  • SREC money: 2.256 * $112.29 = $253.33 per year based on the average amount I earned for selling my SRECs generated between December 7, 2010 and August 29, 2013. Erin of Solar Energy Services tells me SRECs are selling for $124 in 2013 but I expect this price to go down over time.

  • This means the net cost for the Solar Energy Services AET/Vaughn solar thermal hot water system after 10 years is $7900 - $2370 - $500 - (10 * $253.33) = $2496.70, assuming SRECs maintain their 2010-2013 value. If SRECs are worthless, then the net cost after 10 years is $7900 - $2370 - $500 = $5030. The actual value will be between these two numbers and probably close to the lower.

    After 10 years, the cost of this solar thermal system plus its energy costs comes to $2496.70 + (10 * $264.99) = $5146.60 if we assume SRECs maintain their 2010-2013 value. If SRECs are worthless, then the cost rises to $5030 + (10 * $264.99) = $7679.90. The actual value will be between these two numbers and probably close to the lower.


    And the winner is...
    Before I answer that, let's summarize the results. The costs I've come up with are over a 10 year period and include parts, installation, removal of the old system, financial incentives, and energy costs over a 10 year period.
  • Conventional electric storage: If I go this route, it would cost me $9009.60.
  • Conventional electric storage powered by photovoltaic solar panels: between $8598.80 and $12,079.80.
  • Gas on-demand (tankless): $6066.70.
  • Heat pump hot water heater: $7245 if I go with the GE GeoSpring purchased and installed by Arundel Heating and Cooling and $7864 if I go with Airgenerate Airtap purchased and installed by Arundel Heating and Cooling.
  • Solar thermal: between $5146.60 and $7679.90 if I go with the Solar Energy Services AET/Vaughn system.

  • The first two choices are overwhelmingly cost prohibitive. But cost isn't the only factor so I kept my options open for the last three.

    Longevity of the system is something that wasn't factored into the cost. Gas on-demand systems and solar thermal systems will often last 20 years while heat pump hot water heaters will last more like 13. So if we expand our 10 year window to 20 years, then heat pump hot water heaters lose.

    Let's compare gas on-demand and solar thermal over a 20 year period.
  • Gas on-demand: $2580 + (20 * $348.67) = $9553.40
  • Solar thermal: $2496.70 + (20 * $264.99) = $7796.50 if we assume SRECs maintain their 2010-2013 value for 20 years (snowball's chance in hell). If SRECs are worthless, then the cost rises to $5030 + (20 * $264.99) = $10,329.80.

  • Now consider noise. I didn't find anything for the Bosch 980 gas on-demand system but the A.O. Smith on-demand system is rated for 49 decibels. For lack of better data, I'll assume the Bosch 980 is similar. For heat pump hot water heater, Airgenerate AirTap claimed AirTap is 48 decibels while GE GeoSpring is 58 decibels. I could find no information about noise generated by a solar thermal system. As far as I know, it is no louder than a conventional electric tank system. None of these are all that bad but if you have a hot water heater near your bedroom or office, you might prefer solar thermal. According to Comparative Examples of Noise Levels
  • 50 decibels: Quiet suburb, conversation at home. Large electrical transformers
  • 60 decibels: Conversation in restaurant, office, background music, Air conditioning unit at 100 ft



  • Protecting the Environment

    If your energy provider uses coal to generate electricity, then you are doing the environment good by switching to an energy efficient form of water heating. Solar Energy Services claims that if I use their system, I will reduce the total carbon emissions by 1.4 tons per year! I expect emission reduction from the other efficient systems will be similar.

    If you have to use a fossil fuel, natural gas is a good one to use. It is much cleaner than coal or oil and unlike oil, the United States has quite a lot. But if you don't want to be dependent on another source of energy, then perhaps it is just best to stick with electricity, especially if you can add more photovoltaic panels to provide that elecricity. In the end, this is what became the deciding factor for me. My goal is to be net zero in my energy usage and I'll have a much harder time achieving that if I become dependent on natural gas.



    Payback

    I can't NOT get a new hot water heater. Mine is leaking and the leaking is getting worse. So if I get one and want to stick with something similar, though slightly more efficient, I will get the Marathon 50 conventional electric storage hot water heater.
  • After 1 year, the cost for this system plus energy costs will be $2998 + $601.16 = $3599.16
  • After 2 years, the cost for this system plus energy costs will be $2998 + (2 * $601.16) = $4200.32
  • After 3 years, the cost for this system plus energy costs will be $2998 + (3 * $601.16) = $4801.48
  • After 4 years, the cost for this system plus energy costs will be $2998 + (4 * $601.16) = $5402.64
  • After 5 years, the cost for this system plus energy costs will be $2998 + (5 * $601.16) = $6003.80
  • After 6 years, the cost for this system plus energy costs will be $2998 + (6 * $601.16) = $6604.96
  • After 7 years, the cost for this system plus energy costs will be $2998 + (7 * $601.16) = $7206.12
  • After 8 years, the cost for this system plus energy costs will be $2998 + (8 * $601.16) = $7807.28

  • Let's compare this with our other options and see how long it takes one of the other more efficient systems to pay for itself. When I say "pay for itself" I mean that the cost of the system and its energy usage will be equal to or less than the cost of the conventional electric storage hot water system and energy usage. Anything beyond that is savings, or money in your pocket from not going with the conventional electric storage system.

    Consider the gas on-demand system.
  • After 1 year, the cost of this system plus energy costs will be $2580 + $348.67 = $2928.67
  • If you go with this system, then as soon as your get your BGE rebate, it will have paid for itself. Sweet!

    Consider the heat pump hot water system using GE GeoSpring installed by Arundel Heating and Cooling..
  • After 1 year, the cost of this system plus energy costs will be $3632 + $361.30 = $3993.30
  • After 2 years, the cost of this system plus energy costs will be $3632 + (2 * $361.30) = $4354.60
  • After 3 years, the cost of this system plus energy costs will be $3632 + (3 * $361.30) = $4715.90
  • It will take 3 years for this system to pay for itself.

    Consider the heat pump hot water system using Airgenerate AirTap installed by Arundel Heating and Cooling.
  • After 1 year, the cost for this system plus energy costs will be $5279 + $258.50 = $5537.50
  • After 2 years, the cost for this system plus energy costs will be $5279 + (2 * $258.50) = $5796
  • After 3 years, the cost for this system plus energy costs will be $5279 + (3 * $258.50) = $6054.50
  • After 4 years, the cost for this system plus energy costs will be $5279 + (4 * $258.50) = $6313
  • After 5 years, the cost for this system plus energy costs will be $5279 + (5 * $258.50) = $6571.50
  • After 6 years, the cost for this system plus energy costs will be $5279 + (6 * $258.50) = $6830
  • After 7 years, the cost for this system plus energy costs will be $5279 + (7 * $258.50) = $7088.50
  • It will take 7 years for this system to pay for itself. It is a great piece of technology but it just doesn't have the government support that some of the other systems have.

    Consider the AET/Vaughn system installed by Solar Energy Services.
  • After 1 year, the cost of this system plus energy costs will be between $2496.70 + $264.99 = $2761.69 and $5030 + $264.99 = $5294.99, depending on the value of SRECs
  • After 2 years, the cost of this system plus energy costs will be between $2496.70 + (2 * $264.99) = $3026.68 and $5030 + (2 * $264.99) = $5559.98
  • After 3 years, the cost of this system plus energy costs will be between $2496.70 + (3 * $264.99) = $3291.67 and $5030 + (3 * $264.99) = $5824.97
  • After 3 years, the cost of this system plus energy costs will be between $2496.70 + (4 * $264.99) = $3556.66 and $5030 + (4 * $264.99) = $6089.96
  • After 3 years, the cost of this system plus energy costs will be between $2496.70 + (5 * $264.99) = $3821.65 and $5030 + (5 * $264.99) = $6354.95
  • After 3 years, the cost of this system plus energy costs will be between $2496.70 + (6 * $264.99) = $4086.64 and $5030 + (6 * $264.99) = $6619.94
  • It will take between less than one and just over 6 years for this system to pay for itself, probably closer to one.



    Yes, this is my final answer

    All things considered, I decided to go with a solar thermal hot water heating system; the AET/Vaughn installed by Solar Energy Services.


    Roof work
    You don't put a new solar thermal system on a 20+ year old roof. You get a new roof. When doing so, you have the roofer remove the old roof, inspect it, and make any necessary repairs so there will be no issues in the near future that would require both solar panel and roof removal to fix.

    I've had work done by RoofPro in the past. They were prompt, seemed knowledgeable, and got the job done for a reasonable price. Their BBB rating is A+. Two years ago, Adriano Candido reroofed my garage. He did great work but it's often hard to get him to reply or give me an estimate for a start date. I guess it's because he's good. But I'm too impatient for that so I decided to go with RoofPro.

    Bradley H. came out. We spoke for awhile. I ordered the CertainTeed Extra Tough (XT) 25 timerbline asphalt shingles. These should last 25 years. It is the same shingle type on my garage.

    I also got the Leaf Solutions gutter guard which have a lifetime guarantee. I've been fortunate in that I climb up on the roof several times a year to clean out the gutters and haven't had any near falls but I figure my luck will run out. It is a 2 story drop onto the driveway. I'm not getting any younger so I'd rather not take risks I don't have to. I got this installed both on the roof and the garage.

    I asked about getting a vent cap but Bradley said I was better off with my fan since I have a hip roof which doesn't have much roof line.

    He said they would install an ice/water shield which will go over the drip edge. During his inspection, he said there wasn't one under the old roof.

    On May 15, 2013, they finished installing my roof and the gutter guard.

    Over the next few weeks, I observed the gutter guard during heavy rains. It worked just fine.

    There were some spots that didn't quite lie flat so Steven came back on July 23, 2013. I don't expect thing to be perfect the first time around but I do expect a good company to follow up to their customer's requests and make things right. Unfortunately, Steven couldn't really see what I was talking about because it was early in the day and the sun wasn't hitting the roof at the right angle. So I sent him a picture. He replied a couple days later letting me know that he was speaking to his manager to decide how they could resolve this and would get back to me.

    On September 9, 2013, Steven redid the roof. I asked him what caused the initial job to be bumpy and he said they had a bad roll of felt paper that didn't want to lay as flat as it should. Things looked much better once they were done.

    Since the new roof and inspection is needed for both the solar thermal panels and the solar photovoltaic panels I will purchase this year, it qualifies for the 30% federal tax credit. But I'm only going to apply this credit to the cost of the roof, not the gutter guard. The roof costs $5400 while the gutter guard costs $2750. So after I file my taxes, I'll get back 0.3 * $5400 = $1620.


    Installation

    On June 20 and 21, 2013, Bryce and another guy came out to do the installation. On the 20th, they got the collector mounted on the roof (first photo), removed the old hot water heater, and set up the new one, which was much larger than I expected. Before, I used to be able to squeeze between the hot water heater and the wall. Now, even an anorexic can't do that. See second photo. Then the next day they came back to hook things up. I was pleased with their work. They did everything that Rich said they would do.

    My system was operational on June 21, 2013.

    Near the bottom is a round, black display with the words "Grundfos Alpha 15-55F/LC" on it. The reading switches between wattage consumed and gallons per minute. It isn't always displaying. I think it just does when propylene glycol is being pumped between the collectors and the hot water heater. The wattage indicates how much electricity is being used by the hot water heater to actually heat the water in the electric mode. This is separate from the amount of electricity used to circulate the propylene glycol. In fact, they are controlled by different circuit breakers. Circulation is controlled by breaker 8 in my house while the hot water heater is controlled by breaker 16 (prior to December 6, 2013) or breaker 20 (as of December 6, 2013). I can turn off the breaker for the hot water heater and just let things heat in solar mode on a sunny day. Bryce suggests doing that just to see how long we can get by on solar heating without needing the electrical heating element. As long as the sun is out and the propylene glycol can circulate, it will heat the water. Ideal circulation rate is 2 gallons per minute with a wattage reading of 17.

    There is also a "Winters" pressure gauge near the bottom. It should read about 28 pounds per square inch. This relates to the pressure of the propylene glycol.

    Also near the bottom is a small white metal tank with the word "Extrol" on it. This is the expansion tank.

    Near the top is the white Resol DeltaSol AL display that reports several things.
  • COL: Collector reading. This is the temperature on the roof. Reading on June 21: 107.7
  • TST: Temperature in the hot water tank near the bottom. Fresh water coming in is about 60 degrees so if the system is not working, then it will be around 60. It won't be extremely hot because the hot water rises. The heating coils containing the propylene glycol are about 6 inches from the bottom so things should be a good bit warmer than 60. Reading on June 21: 90.8
  • S3: Sensor at the top of the tank. 125 is ideal while 156 is maximum. The pump helps ensure things don't get too hot. But what happens if the power goes out on a sunny day? I asked that and got a reply from Roger, one of the partners, via Erin:
    Your panels are rated for sustained stagnation, so if your power is out for a period of time, no damage is done to your system. It's a bit hard on the glycol, but as long as you remember to have the system serviced (glycol changed) every 3-5 years, all is well.
    Roger has been in the business for 35 years so I'm assuming he knows what he's talking about. S3 reading on June 21: 123.0
  • hP: Hours the pump is operated. Not sure why I should care about this but I'm sure a service technician would want to know. Maybe it is used to determine when it needs to be replaced. Reading on June 21: 0
  • KWh: How much equivalent electrical heat was produced via solar energy. Normally, heat is measured in BTUs but in this case, they measure how much energy we saved by using solar instead of electric. Reading on June 21: 0
  • MWh: The same as above but in megawatt hours. Reading on June 21: 0

  • If we go on vacation, we can turn off the breaker (16) to the hot water heater. The pump is the thing that keeps things from overheating so that should never be off.

    To adjust the temperature of the water, I need to turn the knob above the tank. This ia a grey knob with the words "Moneywell AM-1 Series" written on it. Before turning, I need to loosen the screw in the center of the knob. Turning clockwise (blue arrow) will increase the cold water coming into the tank to lower the temperature of the water while turning counterclockwise (red arrow) will reduce the cold water coming into the tank to increase the temperature.

    Bryce advised me to put a small container under the propylene glycol relief value which is near the bottom, just below the round, black display. He said that there are a few cases (very few) where propylene glycol leaks out. If it does, call them. The system has a 7 year warranty but they typically last 20 years.

    The long vertical copper pipe can be used to drain the tank. This could be good to get out residue that settles at the bottom but shouldn't need to be done often.

    I should definitely get the propylene glycol changed at least every 5 years. This costs $15 per gallon plus $100 for the service call. Our system uses 4 gallons so that means $160. It becomes corrosive as it ages or is exposed to high heat.
    Glycols produce organic acids as they degrade, especially when heated. If left in solution, these acids will lower the fluid's pH. With no corrosion inhibitors to buffer these acids and protect the metals in the system, the corrosion rate of a plain ethylene or propylene glycol solution can be greater than plain water - a highly corrosive fluid in its own right.
    - from Hydratech - Protect your cooling and heating systems against corrosion

    The outside of the tank is plastic while the part the inside is steel with a lining of hydrastone on the inside.

    The propylene glycol mixture gets from the collector to the hot water heater via insulated pipes in the attic. See third photo. From the attic, it gets to the basement through a pipe that goes between the wall in my office and our chimney. There is no way to tell it is even there.
    Click thumbnails to enlarge.


    Journal
    On July 19, 2013, my plumbing inspection was performed by John Hidey while my building inspection was performed by Ken Brown. All good to go.

    On August 5, I noticed a sound that occassionally came from the hot water heater. I hadn't heard it until then because I was sleeping in the downstairs bedroom when my in-laws visited. It sounded like a mix between clicking and water dripping on plastic. But there was nothing leaking that I could see. It occurred about once every two minutes. It wasn't loud, but considering everything else was pretty quiet at that time of night, it was noticeable and made it difficult to sleep. I did not hear that sound in the morning. Roger and Brice think it is the expansion tank and that it can be relieved by running the hot water for awhile. I notice the sound more on sunny days.

    On October 6, 2013, our house was recognized as one of several on the "4th Annual Maryland Tour of Solar and Green Homes." This means it was listed in a booklet and open to the public for the afternoon. What makes our home green? We use solar photovoltaic panels, solar thermal hot water heater, geothermal heat pump, rain barrels, extra insulation in the attic, composting, and a pellet stove which burns fuel made from sawdust and other wood waste. All this in a home built in 1952! The event was a success. I had about 25 attendees, mostly neighbors, co-workers, and kayakers, and there was never any down time. It lasted from 1100 to 1800.

    I've lived in Maryland since 1995 and the 2013-2014 winter was the coldest I've ever experienced. How effective was our solar hot water heater during this time? Much of that depends on if there was snow covering the collector. On February 27, 2014, it was cold and sunny. There was no snow on the collector. The outside temperature was 35 degrees but the temperature in the collector was 125 degrees! Inside the tank, it was 122 degrees. So indeed, even on cold days, as long as it is sunny, our solar thermal hot water heater can operate in solar mode, though I have no doubt it also gets some help from the electric heating unit. Just how much help it gets, I don't know. I would prefer that the electric heating element receive its power from an electric wall socket rather than be hardwired. Then I could use a Kill-A-Watt electric usage monitor to measure its energy consumption.

    On May 11, 2014, I turned off breaker 16 again. In a normal year, I think we could have turned it off a couple weeks prior but it has been a pretty wet spring so far. On October 3, 2014, I turned it back on again. So during the time in between, our water was heated entirely through solar energy.

    The following year, I tried this again but on the day after spring (March 21, 2015). That was too soon. I tried again on April 11, 2015. This was a good time for the changeover. However, we had a very dark early June. After about 5 days of heavy cloud cover and/or rain, I had to turn breaker 16 back on, June 5, 2015.

    In August 2015, I stopped getting hot water. This was very unusual since normally, I don't have to turn on the electric breaker to the heating element until October. Checking the system on a moderately sunny day, the temperature in the collector (COL) read 220 while the temperature at the top of the tank (S3) read 89. I reached out to Erin at Solar Energy Services on August 9, 2015 to inform them of the problem. Peter came out on August 20. He found that the system was low on glycol. The pressure gauge should have been at 35 pounds per square inch (give or take 10, depending on the time of the year) but it was not. Below 25 is a problem. Expect lower pressures in the winter and higher in the summer. He checked for a glycol leak but didn't find one. He tested the remaining glycol for acidity but found that it was fine. He refilled the glycol and things were fine after that. The system holds 4 gallons.

    On August 24, 2015, I noticed a small puddle of glycol under the gray expansion tank for the circulator. Glycol was dripping out the bottom. I checked the sides and they were dry so I'm pretty sure it was only coming out the bottom. The pressure read slightly lower than previously. I turned on the electric heating element for the hot water heater and reached out to Erin again.

    On September 4, 2015, two guys came out to fix the leak. They increased the pressure of the glycol and found a pinhole leak on the lower side of the expansion tank. They replaced it and recharged the glycol to 34 psi.

    Around October 1, 2015, I turned on the breaker for the electric heating element on the hot water heater. Normally, I would have waited until longer but we were getting a lot of clouds and rain for hurricane Joaquin.

    On February 14, 2016, the sun was shining brightly and the air temperature was around 20 degrees. But the temperature in the panel (collector) was 110 degrees!

    On April 14, 2016, I turned off the breaker for the electric heating element on the hot water heater.

    On September 26, 2016, I turned on the breaker for the electric heating element on the hot water heater. We had a very rainy week then.

    On January 22, 2017, the glycol reading was 22 psi, which is about what it read when I reported the leak in August 2015. I expect that the pressure reading might be a little lower in the winter but at the time, the air temperature was 50 degrees and the temperature in the collector is 60 degrees so conditions were rather mild. I reached out to Solar Energy Services. After a couple of days, with no reply, I sent a follow-up email saying "PLEASE REPLY." Then Erin M. replied and scheduled a technician to come out.

    On January 27, 2017, Bruce came out. The glycol reading was still at 22 psi, but he said with a house with just one story, that's sufficient to run the glycol. As long as the psi is at least 20, the glycol should continue pumping. He talked with his boss, who indicated it doesn't seem abnormal to have lost that much psi over the 15 months since it was last refilled to 35 psi.

    You can hear the glycol running when the temperature on the panels is high enough to turn it on (12 degrees higher than the temperature at the top of the tank) by listening to the gurgling in the one horizontal pipe near the bottom of the tank while turning off the one yellow value to the left of it.

    Bruce checked on the roof and in the attic, and it all seems normal with no leaks. He refilled it to 35 psi. He noted this on the side of the tank, along with a note that the glycol was changed out 15 months ago. In a normal situation, the glycol won't need to get changed out for 5 years, but if there are issues, it should get changed out in 3 years. He seemed to think our situation is normal.

    About a week ago, I tried to drain the sediment in the tank but couldn't figure out how to do so. There is a spigot on the side of the tank near the bottom of the tank but that only drains incoming cold water, not what is in the tank. Bruce said that this tank does not need to be drained of sediment due to its construction. I find that hard to believe.

    On April 9, 2017, I turned off the breaker for the electric heating element on the hot water heater. I had to turn it back on after several days of no sun but once the sun came out, I turned it off again. The spring of 2017 is starting out rather dark.


    Money saved
    The system became operational around noon on June 21, 2013. Naturally, a lot of energy (either solar or electric) was needed to get the cold water in the tank hot. But after that, it went into more of a maintenance mode. Of course it takes a lot less energy to keep something hot that is already hot than to heat up something cold. So for the first day and a half, I really don't care how much energy the system used or how much it saved me.

    What I do care about is how much energy was used starting at the end of day two. On the evening of June 22, 2013, the Resol DeltaSol AL display let me know 39 kWh of electricity was offset since the system was activated. This means that if an electric hot water heater were used, I would have paid for 39 kWh but instead, this electricity wasn't needed since solar provided the energy.

    On June 24, 2013, I shut off breaker 16 which powers the electric heating element in the hot water heater. Thus, the only heat being generated is a result of solar energy. Due to some mix-ups in turning breakers on and off, I ended up not being certain of exactly when I was able to obtain sufficient hot water without using the electric heating element but I estimate it was sometime around early October.

    On August 5, 2013, I started measuring the energy usage of the pump that circulates the propylene glycol mixture from the collector to the hot water heater. Since we're still not using electric heat, all the electric energy used for creating hot water will be monitored by a Kill-A-Watt electric usage monitor. See my August 23, 2013 entry under Electricity Offset.



    Electricity offset

  • On June 21, 2013, my solar thermal system reported that it offset a total of 0 kWh over its lifetime.
  • On June 30, 2013, my solar thermal system reported that it offset a total of 238 kWh over its lifetime.
  • On July 31, 2013, my solar thermal system reported that it offset a total of 932 + 390 = 1322 kWh over its lifetime. On July 19, more photovoltaic panels were installed. The electrical work resulted in the hot water heater monitor to be reset after giving a reading of 932. The reading of 390 was approximated since I was on holiday for the week.
  • On August 5, 2013, my Kill-A-Watt electric usage monitor reported that the propylene glycol pump used a total of 0 kWh.
  • On August 15, 2013, my solar thermal system reported that it offset a total of 932 + 977 = 1909 kWh over its lifetime.
  • On August 23, 2013, my Kill-A-Watt electric usage monitor reported that the propylene glycol pump used a total of 2.11 kWh since August 5, 2013. This means that over 18 days, the solar thermal system used 2.11/18 = 0.26375 kWh per day since the breaker for the electric heating element was shut off. In contrast, my old hot water heater reported that for an average family, it used 4959 kwh per year or 13.5863 kWh per day. Of course with just Norma and me, we are smaller than your average family but since it was 19 years old, it probably wasn't as efficient as the yellow sticker reported. In either case, the solar thermal hot water heater's electric consumption during the summer is 0.26375/13.5863 = 1.94% as much as the expected daily energy usage of our old electric hot water heater.
  • On August 23, 2013, my solar thermal system reported that it offset a total of 932 + 977 + 207 = 2116 kWh over its lifetime (64 days). On August 16, 2013, a new net meter was installed. That might have caused things to be reset. Or, maybe the kWh readout only has room for 3 digits and reset after 999. Regardless, the solar thermal hot water heater offset about 2116/64 = 33 kWh per day during the summer. But this just doesn't add up. My old electric hot water heater used about 13.2863 kWh per day (likely much less since that is for an average family). This means that even if the solar thermal system isn't using any electricity, it can't possibly save me more energy than what the old electric hot water heater used. That would be like having a conventional car where you use on average a gallon of gas every day and then replacing it with an electric car that says it is saving you two gallons of gas every day.

  • Actual Payback

    In May 2014, I received my $500 energy grant money from the state of Maryland.

    On October 11, 2014, I submitted an on-line BGE application to be enrolled in the Peak Rewards program for water heaters. This will give us credits towards our winter energy bill. Even if we already have credit from generating energy during the summer, we can still accummulate credit from Peak Rewards. On October 24, 2014, the technician came out. He inspected our breaker box. Breaker 20/22 is what controls the heating element to the hot water heater. It is a 20 amp double pole but it needs to be 25 or 30 amp for them to install a switch. That evening, I went out to Home Depot and purchased a 30 amp breaker. See first photo. I confirmed with Roger Perry of Solar Energy Services that this would not be an issue with our hot water heater.

    On November 14, 2014, we had BGE come out and set up a switch so they could control the heating element of our hot water heater. I made sure they didn't touch the breaker or the outlet that controls the device that circulates the glycol. In the second photo, the outlet with the black power cord controls the circulator. That is not under control of BGE. The orange wire is controled by the 30 amp breaker and leads to a box that BGE monitors and controls. This then leads to the heating element. Since installation, we have been getting credit from BGE for the PeakRewards program for water heaters:
  • November 2014: $12.50 credit

  • I have been receiving 2.256 SRECs per year. As of November 19, 2014, I have received $247.22 in SRECs.