Avg. system professionally installed for 2-4 persons      $9,000

State Rebate and Federal Tax credit                                        $4,500

Your investment                                                                                   $4,500

Avg. cost/year of hot water for family of 4                               $850

Cost saved per year with solar system                                     $635

System payback period                                                                   7 years

Avg. system lifetime                                                                          25 years

Yes, that would be 18 years of virtually free hot water!  And remember, this estimate is based on today's fuel prices, so as the prices go up the pay back period will decrease and savings will increase.  That, ladies and gentlemen, is a deal to make nearly any Mainer smile.  Now the bad news (sorry, but the sweet always comes with a little sour), the $2000 Federal tax credit will most likely not be available after 2008.  It's an ugly and complicated story involving your national legislators (what a surprise!) and the big energy companies (another shocker!), but suffice it to say that you have until New Years Eve 2008 to get this deal. 

A solar installer told me last week that he was booked out 2 months and hence the urgency of this column.  Mull it over, do a little research, get an estimate, but get off your duff and get it done in 2008!

First a primer. There are two types of solar panels you might have seen on a neighbor's roof (although they can be mounted anywhere there is sun):  Solar thermal, which produces heat for hot water and photovoltaic, which produces electricity.  Both are great technologies and very much ready for prime time, BUT solar hot water technology is much more cost effective.  Initial investment costs for photovoltaic are higher (est. $20-30,000) and payback times are 15-20 years, even with rebates and tax credits.  Don't get me wrong, I think photovoltaic systems are a great idea, especially when tied to our existing electrical grid, but the investment costs are high.  Truth be told, electricity from the grid is still a pretty good energy deal if used wisely and is much more regulated than oil and gas so the price is more stable.  When was the last time you saw electric rates double in a year like oil or gas?

Solar hot water systems consist of collectors (often roof mounted) that concentrate the available heat from the sun, a set of pipes that carry the heated collector fluid to and from a storage tank (usually in the basement or utility room) and a pump with controls that turn it on and off at the right times.  There are lots of choices to be made, including various types of collectors, storage tanks, and controls, but in the end they all serve to collect clean, cheap heat from the sun and put in your hot water tank.  Can you heat your house with it?  Well, maybe--but you'd need a extremely efficient house and a very large collector system.  For this article we're just talking about the hot water from your faucet. 

Will you need back up? Absolutely yes!  This isn't the tropics, but the system on my house has provided 80% of our hot water needs year-round, and that's with two teenagers on the premises.  Solar systems are compatible with existing electric, gas, and oil fired systems so installation usually involves connecting into and supplementing the existing system.  Every house is different so it will be helpful to have the advice of an experienced installer.  If you send me an email, I will send you a list of installers I know in the area and other resources on solar hot water.  Coming up soon, Fri/Sat April 18/19th, is the Midcoast Sustainable Energy Expo in Damariscotta, a great opportunity to see different systems up close and talk first-hand with installers.  Want do it yourself?  I installed 80% of my system but I had some good design advice and technical help, and I would recommend the same for you.