Let's say you purchase a $ 30,000 solar power system. You take the 30% Federal Investment Tax credit, so after the first year's spring, your system's value is $20,000. Your system will have a 25-year warranty life that can be transferred to the new owner. Take the 20k value and divide it by 25 years. That would be $800 dollars in depreciation per year. So if you sell your home in 5 years, the value of the system (price you can add to the value of your home would be: $800.00 x 5 years = $4,000.00, so you can add $16,000.00 to the price of your home, and you will have saved well over $4,000.00 depreciation in electric bills. In total, after only 5 years, you probably would save in the neighborhood of 2-3k. So as you can see, it is worth it, because you get your money back and more after only 1 year.