Single and Multi-Stage Furnaces. Whats that all about?
A. If you were designing a new home it is possible to lay out the ducting system separating the air flow between floors or house wings creating “zones”. A multi-staged furnace will operate to supply the first zone at a lower rate of air flow and gas consumption, and will pressurize that zone allowing an even flow of air and heat. When a second thermostat calls for heat in another zone, the blower speed will increase and the gas burner will move to full power to accommodate the added requirement. The fuel saving is in using only about two thirds of the furnace capacity for part of the time. As we are dealing with the replacement of oil or electric furnaces to natural gas in existing homes with existing ducting systems, we do not have the luxury of redesigning ducting, and have to work with a given set of circumstances in often fully finished homes with closely built-in furnaces and ducting. In order to achieve a pressurized duct system allowing an even air flow at comfortable temperatur
