The residential boiler market in the U.S. is somewhat small when compared to the rest of the world. In fact, according to some estimates, only about 9 million U.S. homes are heated with boilers, 60 percent of which are in the Northeast. Most single-family homes in the U.S. — about 35 million — are heated by forced air furnaces. The situation is exactly the opposite in Europe, where boilers heat the vast majority of homes.
Still, boiler service and installation keep a number of contractors very busy in the U.S., as homeowners who have experienced hydronic heat are often life-long fans of the technology. And as they have moved from the Northeast to other parts of the country, they have taken their love of hydronic heat with them, creating demand for service all over the U.S.