1 Solar-powered home water heaters cost $1,000-$3,500 (including installation) but have extremely low monthly operating costs and can be used in any climate, according to the US Department of Energy.2  The cost for a solar heating system can vary widely. The most cost-effective solar heating systems usually provide 40-80% of a home's heating needs; it's often impractical to supply 100 percent of the heat needed and most building codes and mortgage lenders require a back-up heating system, according to the US Department of Energy.