Solar Water Heater or On demand?

[nanasohana]

So is the requirement now a solar water heater or can you have an on demand instead?

[hotinhawaii]

You can have a propane on-demand heater instead of solar on a new home. You can not have electric though to meet new requirement.

[Ryan.]

Will this choice remain (solar or on-demand)? Or are we phasing into solar only in order to meet code?

[TonyB]

Aloha friends,
You can get a waiver on solar and get "on demand" as long as you have two other appliances that will be on propane. (stove and clothes dryer). Depending on size of house and where the on demand is located there is a lag period before you will receive hot water. "On demand" costs about $1,500, Solar costs about $5,000 with a State refund of some sort, I think $1,500 but not positive. Solar will pay for itself in about three to four years with regular usage, thereafter hot water is free. If you have the $ go green and go solar.
Best, Tony

[nanasohana]

That is great. I love that, because it is a lower cost for those on tight budgets but still much more energy conserving than the old tank water heaters. As a person has more funds, adding a solar water heating system to the demand would be even more energy conserving. Also, if there just isn't any sun, the demand could then produce the heated water. At least, that is my thinking.

[Kapohocat]

quote:

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Originally posted by Nancy Fryhover

That is great. I love that, because it is a lower cost for those on tight budgets but still much more energy conserving than the old tank water heaters. As a person has more funds, adding a solar water heating system to the demand would be even more energy conserving. Also, if there just isn't any sun, the demand could then produce the heated water. At least, that is my thinking.

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Nope, overall that would a larger carbon footprint to add an on-demand to a solar water heater, and redundant if you are talking budgets. The solar heater flips to electric when there isn't enough sun. The new panels dont need as much sun either to heat them up.

The larger footprint isn't just about the usage but also the mfg process.

[DanielP]

So Cat,

Why couldn't the electric backup heater be turned off and the demand heater be installed in-line between the solar and the house with a standard tempering valve? Or, couldn't the propane demand heater be used instead of the electric back-up?

Dan

[TonyB]

Aloha Friends,
Cat, I think what Nancy was trying to say was..go with cheaper "on demand" system first and then upgrade later to solar when one can afford it, but keep on demand if needed on cloudy days...if I'm reading her response to what I posted correctly.
Aloha, Tony

[Kapohocat]

quote:

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Originally posted by DanielP

So Cat,

Why couldn't the electric backup heater be turned off and the demand heater be installed in-line between the solar and the house with a standard tempering valve? Or, couldn't the propane demand heater be used instead of the electric back-up?

Dan

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Not if you want any of the few credits still left. I guess it could be done that way but it seems more complicated and expensive to add pieces. Honestly I think you'll find that the solar water heater rarely needs to go on, so most of this is academic anyway.

PS @ DanP, dont forget the re-circ pump!! lol[]

Catherine Dumond
Blue Water Project Management
http://bluewaterprojects.blogspot.com/
808 965-9261
"We help make building your dream home a reality"

[nanasohana]

Yep, Tony, that is what I mean. Also, how about a homemade solar "preheat" water tank to send to the on-demand to "finish" heating the water?