Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Solar Preheating for DHW & Radiant???

david_21 Member Posts: 9
In the keeping it simple category... perhaps the solar indirect tank supplied a Polaris type heater. I know that there are differing opinions on the Polaris for DHW and heating, but if the radiant needs weren't large and the DHW needs were (6 people in home)... maybe it could be a fairly simple solution.

Location by the way is Virginia with a very good southern orientation available. I don't think the goal is to rely completely on the solar, just to make a significant contibution.

Many thanks,



  • david_21
    david_21 Member Posts: 9

    Anyone have any good or bad experience tying a solar water heater into an indirect tank for DHW and radiant? Certainly would need to use the boiler exclusively for night and cloudy days, but on sunny days, I would think this could add a significant amount of heat to the home's needs.

    Thanks for your thoughts.

  • hr
    hr Member Posts: 6,106
    A dual coil tank

    could be used to suply DHW and some radiant load.

    Run some calcs first, generally the temperature you get from solar in the winter, and the amount you can store in a typical tank,doesn't buy a lot of space heating time.

    The DHW preheat is still the best buy for your solar dollars. Simple to install and control.

    You always need some sort of a back up source however.

    hot rod

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • MikeL_2
    MikeL_2 Member Posts: 461

    We use an Enerworks 2 panel system that preheats a separate 50 gal tank via their own heat exchanger. That tank in turn feeds a 40 gal Amtrol Indirect that is heated by our boiler. In the summer, in SW Ontario, the 50 gal tank can easily reach 190F and provide all our DHW needs with no further boiler requirement. In the winter, we might get 100-125 F out of the tank at best. So the boost from the indirect is needed.
    Having watched it for 2 years now, I'd say that we are saving about 60% relative to no solar.
  • hr
    hr Member Posts: 6,106
    First define how much

    HW you really need. I've found most families will use every drop of DHW I supply them.

    OR,they learn to adjust their useage around what a solar can easily supply. I get showers all summer on just SDHW. One panel and a 65 gallon tank will get me through 3 no sun days.

    If in fact you need a lot of DHW either have enough dump load storage from the solar or size a heater to provide it on an instantanous basis.

    Solar preheat with an instantanous WH designed to work with solar preheat would be a nice simple inexpensive package.

    Then a mod con sized and designed for the heat load.

    I sure would not subject my family to the bacteria potential that a combined DHW/heat system so easily provides :)

    hot rod

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Mad Dog_2
    Mad Dog_2 Member Posts: 5,871
    Yeah...every drop they can get.................................

    They WILL get used to what they have (even a 5 gal. dom. coil) UNLESS, you just installed a new system for them that won't meet their "demands." As HR said, Do your homework on what THEIR needs really are, then size accordingly. Every family's usage will be slighty-greatly varying. Also, as HR suggested a Small Mod/Con would be a better all-around choice to augment the DHW and space-heating loads...it will be better performing, safer, and longer-lasting. Mad Dog

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Low-tech solar

    I live in Alaska, where the groundwater comes out nice & cold all year. I was wondering if it would be worthwhile for the non-freezing months, to suspend some black poly tubing on the sunny side of the house or use a pressure tank of some kind, to prewarm/temper the incoming water.
    Our natural gas just went up 30%, but it's still supposed to be among the cheapest in the nation. I'm just looking for a cheap & easy way to lower the utility bill.

This discussion has been closed.