Currently my house has a natural gas-burning hot water heater, with a 40 gallon (150 liter) tank. Given the vintage, the efficiency of this heater is likely around 80%. A new, drop-in replacement would be over 95% efficient, based on what's on the market now.
However, as I'm considering this upgrade, I also want to evaluate the possibility of a solar thermal system.
What tools and resources are available for me to understand if a solar hot water system makes sense for my situation? Will the cost savings and/or environmental benefit justify the added expense?
Some notes on my house and needs:
- Two people live in the home
- We've never run out of hot water (150 liters is more than sufficient)
- Hot water is used for showers, hand-washing, and our small dishwasher
- The south face of our roof is unshaded