Clean Power

Published on October 21st, 2013 | by Nicholas Brown


My First Solar Water Heater — A 2-Year Review

October 21st, 2013 by  

Originally published on Green Building Elements

I have been using a solar thermal water heater for nearly two years, and am now ready to share my experience with it.


First: solar thermal water heaters (often just called solar water heaters) operate by absorbing sunlight into insulated (by vacuum) glass tubes where it turns into heat. That heat accumulates in the water until it becomes adequately hot. The hot water is stored in a tank.

Apart from that, the heater was said to be equipped with a built-in auxiliary electric heater to ensure that hot water is always available, regardless of weather or time. That electric heating element was never plugged in, and the heater has been providing hot water even on cloudy days!

This is made possible by the simple, yet amazing technology of insulation. The heater heats the water during the day, and insulation keeps the water hot throughout the day.

It is a 53 gallon rooftop unit with a retail price of approximately $1,100, including installation, but that was reduced even further by a discount.

It paid for itself in one year because it reduced the monthly electricity cost by $50. That is what the previous 1980s heater cost, and it provided less hot water! (it was 20 gallons)

Follow me on Twitter @Kompulsa.

Check out our new 93-page EV report, based on over 2,000 surveys collected from EV drivers in 49 of 50 US states, 26 European countries, and 9 Canadian provinces.

Tags: , , , , ,

About the Author

writes on CleanTechnica, Gas2, Kleef&Co, and Green Building Elements. He has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is:

  • saniconenergy

    The solar water heater comprises of two parts viz., solar collector (which absorbs sun radiations & transfer the heat to water) and a storage tank, which stores the water heated by the solar collector. The most commonly used collectors are of two types, Flat Plate Collector also referred as FPC, which is usually a flat insulated box covered with the glass and a bunch of tubes , usually of copper. This tube is covered & welded to the wide fins,usually of Aluminium painted with high absorption coatings such as TINOX.

    The other type of collector is the evacuated tube collector also know as ETC. This comprises of hollow glass tubes with anti reflective coating inside. This tube contains a metal pipe usually of Copper placed in the center. The metal tube is hermetically sealed with glass tube and the air inside is sucked to create sort of vacuum.

    The collectors are placed on the rooftop facing the south in northern hemisphere and north in southern hemisphere.The solar collector turns the sun’s radiation into heat which is then transferred on the the water inside these tubes.

    The heated water is transferred to the storage tank either through the pumps, which is controlled by the solar controller or if the tank is placed on the top of the collectors then through thermosiphon (hot is lighter thus rises, cold is denser, heavier thus settles down).

    In case of non sunny days or fluctuation in hot water demand, The solar water heater is backed up by auxiliary heating which could either be of gas, electric, heat pump etc. It is always recommended to install a thermostatic mixture in the solar water heater so as to prevent scalding if the temperature of the water rises exceptionally.

  • Raheel Nizam

    I there anyone Know, that solar Heater is no harmful for human health ?

    • Bob_Wallace

      I suppose one could build a solar heater using harmful materials, but I’m not sure what those would be. Even some lead solder (which no plumber would ever use) on copper pipes shouldn’t be a problem with water which isn’t being drunk.

      I suppose that if one was using solar heated water for cooking then they might want to have their water checked.

      There are millions and millions of solar water heaters in use around the world. Were there any problems we should know about them by now.

  • Rod

    This is an excelent project. Hope that you can manage to get your solar heater working properly, as it will help you to reduce energy bills.



  • Solardiamond

    Personally I see no reason to belittle him taking the time to say, “solar water heaters are good,” It seems he has a batch heater that holds the heated water on the roof. Unless some provisions have been made to avoid freezing, this would not be ideal in cold climates.
    Having installed over 300 SWH’s, I can advise you to purchase a drain back system that uses water as the heat transfer agent. When heat is not available in the collectors, the approximate 6 gallons of, your heat transfer agent, water, safely “drains back” into the tank itself. I prefer using the coil of copper tubing, in the bottom of your water heater, not only as the heat exchanger but as the container of the “transfer” water. This requires only one pump on the entire system.
    The main thing to remember is tilting your collectors one-quarter of an inch, that the water will drain back to a safe place.
    BTW: PV is the true future of solar; yet, thermal solar, heat to heat transfer, is extremely efficient.
    Jim Lindsey

    • cmu

      ‘I see no reason to belittle him taking the time to say, “solar water heaters are good,’
      This is a post in a supposedly serious website on technical & sustainable issues, and it contains absolutely NO information. It should be ridiculed. Many commentors (including you) have more details than the original, for which thanks.

      • Solardiamond

        I do understand. If I can be of more help, please let me know.
        Jim Lindsey

  • SirSparks

    I have a very small system I installed myself also 2 years ago. It has just three 2ft x 2ft panels and a 16 gallon storage tank which is plenty for 2 showers a day when mixed with col water (my latitude 28 degrees; Tampa Fl) On a normal day a temperature controller will shut down the circulation to the tank or the temperature would get too high.
    I do have a 1 Kw (PV/battery powered) direct flow temperature booster which will raise the temperature a few degrees IF required but I virtually never use it.
    I am very happy with mine.

    • S.Nkm

      Your comment’s more informative than this post.

  • I should note that there are similar solar heat systems that also use vacuum tubes around the collectors; but that do not have the water tank enclosed in the header. This is a self-contained system, apparently, but as far as I know, the more common type uses a hot water tank/heater in the basement, or inside the building.

    These systems are very efficient, because of the vacuum insulation, and they are in use in many places and by lots and lots of people. China, in particular has thousands of them, and they do indeed pay for themselves quickly.

  • Steeple

    Just got back for a tr to Greece and Turkey. These things were everywhere. Nice.

  • Andrew Gebert

    Another detail, sir: Your latitude, please.

  • cmu

    I must be dense. You say ‘share my experience with it’ after 2 years, and all I see is a simplistic description of a SWH, and an equally simplistic economic “analysis.”

    Where are any details of purchase (brand), actual technology (does it use a pump?) installation issues, size (can I put one on my garage roof,) licencing issues (did your DOB blanch?), maintenance schedule, subsidies available, etc, etc.?

    Is there a whole another section missing? My 14-yr old could’ve written this, without ever installing a SWH.

    • brink

      what is your point, payback period should have sufficed on this one. no problems obviously.

Back to Top ↑