An oversized furnace isn’t a better furnace. Too much heat can actually make your living spaces less comfortable in winter, not more. It’s also wasteful from an energy efficiency standpoint, as well as a from a financial one.
In the past, residential furnaces were often “one-sized” rather than installed on the basis of an accurate load calculation of the actual thermal requirements of the home. To cover for the inevitable errors in this process, builders and contractors simply installed a furnace that was too big for the job. Many homeowners are stuck paying for these past mistakes.
Here are some of the ways an oversized furnace is bigger but not better.
While an excess of output may be a benefit to blast a freezing house with heat, that oversized approach quickly becomes a liability. Rooms closer to the furnace will often become uncomfortably hot and, as the thermostat responds to the abrupt influx of heat, the system will rapidly cycle back off before other rooms farther away have adequately warmed.
Because a furnace reaches its manufacturer’s efficiency specs only after it’s reached full operating temperature, an oversized furnace that cycles on and off rapidly never reaches that point. It’s always warming up and never reaching the most efficient mode. A notable feature of high-efficiency furnaces is that they operate at low output but run almost all the time, cycling off very infrequently. An oversized furnace does the opposite.
Shortened Service Life
The on/off operation of oversized furnaces stresses the most expensive components in the system: the heat exchanger and blower motor. The metal in a heat exchanger expands and contracts with each heating or cooling cycle. Frequent cycling may induce stress cracks in the heat exchanger that can leak dangerous carbon monoxide gas, as well as render the furnace unrepairable from a financial standpoint. Like any electric motor, constant on/off operation inflicts excess wear and tear on the blower, leading to early replacement.
For more reasons to avoid an oversized furnace, contact the pros at Rodenhiser Plumbing, Heating & Air Conditioning. We’re proud to serve homeowners in the Route 495/128 area of Massachusetts.
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