Historically, the most robust solar heating markets have been in warm-weather states such as Florida and California. Consequently, the solar heating industry in the United States has developed an emphasis primarily on solar pool heating and solar domestic water heating systems.
Trends show the market for solar combisystems — systems that provide both domestic water and space heating — has potential to expand. An estimated 42,000 of these systems are installed in the United States, and the market is growing slowly.