The Veredict on Solar Water Heater....

Numbers are in, and they confirm that the decision of buying a solar water heater was the right one.

For those of you who don't live here in Hawai'i, the cost of electricity is astronomical (besides, we don't have natural gas distribution system so all appliances are electric). The price per kilowatt hour has increased from $0.34/kwh to $0.46/kwh from last August to this August (ouch!). The main increase comes from what the utility company labels on our bill as "energy cost adjustment" this is what they feel like charging for the increasing cost of fuel. This cost has gone up in that same period from $0.11/kwh to $0.20/kwh.


Here is the monthly electricity use of our house for the past year. The solar water heater was installed in late December, so the January bill does not really reflect the solar heater, and February was extremely cloudy....

Month-------kWh used
Aug 07-------664
Sep 07-------595
Oct 07------- 737
Nov 07-------574
Dec 07-------622
Jan 08-------588
Feb 08-------555*
Mar 08-------295**
Apr 08-------460
May 08-------361
Jun 08-------296
Jul 08-------345
Aug 08-------261

*this was a major disappointment for we were expecting a much bigger drop
**this was more like it!

Besides the water heater we also replaced all the incandescent light bulbs for fluorescent light bulbs in the house, and stopped using the clothes dryer (instead we used the solar clothes dryer that came with the house - clothes line - it really works!) unless totally necessary (sometimes clothes take up to 3 days to dry)

So, crunching the numbers we get that prior to the solar water heater and other energy saving changes made to our lifestyle, our monthly average electricity use was 630kWh.

After the solar water heater and other changes our average monthly electricity use is 336kWh. This is an average reduction of 47%!!!

We estimate that we have saved since February approximately $775......!

Our cost of the water heater (after utility rebate, federal and state rebates was approximately $1,500.00).

So, solar water heater? YES!