Article #136 - Bigger is Not Always Better with HVAC Systems
Determining the correct size of residential heating and cooling equipment is key to achieving comfortable interior conditions, temperature, and humidity, and saving on initial and operating costs. The size of the cooling systems is particularly critical for optimal energy efficiency and comfort. When equipment is oversized, initial costs are higher, efficiency is reduced, energy costs increase, and comfort may be compromised.
Correctly sized equipment is especially important in humid climates where short-cycling of air-conditioning equipment can lead to poor humidity control. Similar to an automobile in stop-and-go traffic, the overall efficiency of an air conditioner, furnace, or heat pump is reduced by excessive cycling. More starts and stops accelerate wear and tear on the equipment, which can lead to premature failure.
Oversized systems also use more fan power for the blower and often exhibit more duct leakage due to higher-operating duct pressures. Finally, oversized air conditioners and heat pumps aggravate the summer utility peak demand on hot days. In some studies, a 13% higher summer peak electrical demand was correlated to oversized units.
To learn more about sizing HVAC systems, please see the article on How to Size HVAC Systems Correctly .
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