Popular high-efficiency boilers tend to be more expensive at installation, but lower utility bills pay customers back over time. In fact, the U.S. Department of Energy estimates that replacing an older boiler system with a new, high-efficiency one can cut fuel bills by up to 40%. However, to protect that investment, high-efficiency boilers need to be properly maintained, just like you would with a car.
Two key parts of a boiler are the heat exchanger and heat engine. Put simply, the heat exchanger transfers heat from the combustion process into the water that’s circulated through the building. The more energy the heat exchanger can transfer, the more efficient the boiler is. High-efficiency boilers extract heat so efficiently that the flue gases leave the boiler at temperatures low enough that they actually condense inside the heat exchanger.