[Greenbuilding] Water heater timer energy savings?

[Antonioli Dan]

Sacie, 

A net zero hot water system starts with a solar thermal heating strategy, backed-up by solar electric. If a solar thermal system generates, on average, 80% of the hot water then you only need to supply 20-25% of the “back-up” electricity to heat an electric hot water heater. 

An electric hot water heater that has solar dip tubes is one way to go, another is one that has an integral heat exchanger in it. Or you can pay the extra buck to mount an extra two loop system. 

Regardless of how  you go, the primary year-round heat is from the sun. The backup is from solar electric resistance. 

As California moves ever closer to the year 2020 when all new residential construction has to be net-zero energy I think this will be the hybrid system of choice. There are some very new systems coming online that might change the equation, but either way it will be net-zero energy. 

As ever, it depends on whether or not you can get the teenagers to take reasonable showers!

Dan



On Apr 10, 2016, at 4:33 PM, Sacie Lambertson <sacie.lambertson at gmail.com> wrote:

> Dan, what is a net-zero energy hot water system please?
> 
> A PV set-up that produces sufficient hot water you don't have to purchase the gas/electricity to heat water?
> 
> We plan to install some PV but I'm trying to figure out/balance what is 'sufficient' with cost.
> 
> thanks, Sacie
> 
> 
> 
> 
> And all of this aside, investing in solar thermal is the best overall strategy for reducing hot water energy waste. I’d rather put the time and energy into a net-zero energy hot water system

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/greenbuilding_lists.bioenergylists.org/attachments/20160410/8aeb93d2/attachment.html>