Forced hot water (“hydronic”) heating systems use circulator pumps to move heated water from boilers to radiators and back. These pumps run whenever a thermostat calls for heat.
Pumps have a spinning shaft called a rotor that is rotated by a magnetic field created by coils of wire that surround it. The spinning rotor circulates water through the boiler distribution system.
Traditional circulator pumps run at one fixed speed and use some electricity to magnetize their rotor. Electronically commutated motor (ECM) circulator pumps can modulate their speed and use permanent magnet motors that don’t require any electricity to have magnetic properties. ECM circulator pumps provide a number of advantages:
|1||Permanent magnet motor||The rotor does not consume electricity to act as a magnet.||Reduced electric bills|
|2||Variable speed||Speed adjusts to match the load. If only one small zone needs heat, then the pump can run slowly. If a large, distant zone needs heat, the pump can speed up to keep a constant flow or pressure. Only the power that is needed is used.||Reduced electric bills and possibly longer life|
|3||Variable power||To avoid jams caused by sediment collecting after prolonged periods without use, some ECM pumps are programmed to start at full power and then ramp down to match demand. This can clear sediment that could otherwise jam the pump.||Reduced service calls|
|4||Variable direction||If sediment causes a pump to jam, some ECM pumps can automatically reverse themselves temporarily to attempt to clear the jam.||Reduced service calls|
Combining these energy-saving features, ECM circulator pumps use about 85% less electricity than traditional pumps. For a typical home, each ECM circulator pump can save approximately $16/year*. For an ECM circulator pump that costs $50 more than a traditional pump, that’s a three-year payback. And for a pump that lasts 20 years, that $50 investment could save $320. In commercial applications with larger pumps that may run more, the savings can be many times higher.
* This example assumes replacing an 87.7 watt PSC pump with a 14.4 watt ECM pump running for 1,374 hours per year at a cost of $0.16/kWh. Your savings may differ.