The Energy Savers Blog came out with some figures on the economics of Solar Thermal:
(from Ernie Tucker, editor of the weekly EERE Network News newsletter and a member of NREL's Communication Office)
....... I began wondering about adopting a solar water heating system for our Colorado house. Because I'm pretty sure coiling a few lengths of garden hose on the roof won't cut it, I began wondering if an installation made sense.
It was then that I checked out the Energy Savers site on the economics of solar water heaters. Not surprisingly, solar water heating systems usually cost more to purchase and install than conventional water heating systems. The good news is that a solar water heater can usually save you money over time, depending on variables such as the amount of hot water a consumer uses and the cost of the conventional fuels. On average, I could cut our water heating bills 50%–80%.
Even better, the economics make sense for a refinancing. In the Energy Savers example, the price of a solar water heater in a new 30-year mortgage usually amounts to between $13 and $20 per month. But a federal income tax deduction for mortgage interest attributable to the solar system reduces that by about $3–$5 per month. So if fuel savings are more than $15 per month, the solar investment would be profitable immediately......
For the complete article, click here.