It is a sad fact, but if you don’t get any sun, you don’t get any solar heat. But even the grayest areas of the country get a significant amount of sun. Thermomax, a is a Canadian company that uses European technology to provide solar hot water products. Its web site has done a great job of crunching the numbers to see how much water can be heated by a solar unit given the amount of sun available by region in Canada. Its regional comparison page can be found here. They also have a great set of interactive, audio enhanced graphics that explain how solar thermal energy systems work in various configurations. They can be found here.
I will be using their charts to get a better handle on how much money I have saved in the 4 years since I installed my system and will report back to you in a future blog entry.