The term refers to a supplemental heating system that activates when the primary heating source is insufficient to meet the thermostat’s temperature setting. This secondary system provides additional warmth during periods of extreme cold, ensuring consistent and comfortable indoor temperatures. For example, a heat pump might rely on electric resistance heating as a backup when the outside temperature drops below a certain threshold where the heat pump’s efficiency diminishes.
Deployment of a supplemental heating system is crucial for maintaining consistent comfort levels and preventing strain on the primary heating system during peak demand. This can prolong the lifespan of the main heating unit and reduce the likelihood of system failure during critical times. Historically, supplemental heating has evolved from simple wood-burning stoves to sophisticated electric and gas-powered systems, reflecting advancements in heating technology and energy efficiency.