It’s been almost a year since we installed the solar hot water system. It provides both domestic hot water and supplemental heat for our radiant floor system.
We learned several usage tricks early on, and they have not changed over time. We need to plan on doing most laundry and major hot water usage in the afternoon on a sunny day. This helps avoid using the propane heater.
The high angle of the panels means that we do not need to cover them during the summer. We may still need to cover one panel around the fall equinox. We’re not using much heat yet at that time, but the lower angle of the sun means the panels sometimes collect too much energy.
We’ve had a few instances where we got some kind of bubble in the system, which made the panel temperatures soar. The pumps would not turn on to circulate the fluid. We’ve purged the system, and hopefully that’s solved that problem.
We’ve reduced our propane usage by about half over the course of the year. We may do a bit better now that we know how to handle the system.
The payback period for the system is very long. The total installed cost was about $17,500. We saved about $1,600 in propane this first year, making the payback period about 11 years. That could change if the price of propane rises, but it could also change in the opposite direction. I still think that it was a good investment in the long run, though.