When you’re planning to replace an old air conditioning system, or perhaps install a new air conditioner for a home that doesn’t have one, you’ll encounter a number of important choices about what type of unit to get. Perhaps the most important question to answer is, “How powerful an AC do I need?” Unfortunately, people tend to answer this question incorrectly because they automatically favor going larger than going smaller.
Although this is a mistake, as we’ll discuss in a moment, the logic behind it makes sense to non-professionals. The assumption is that a larger air conditioner will at least be able to get the job done that a smaller one can’t, therefore it makes sense to err on the side of too big.
Why This Is Assumption Wrong
An undersized air conditioner will obviously struggle to keep a home cool. But an oversized air conditioner has its own set of problems that will result in higher utility bills, poor distribution of comfort, numerous repairs, and a shortened system life. The reason is short-cycling.
Short-cycling is when an air conditioner’s compressor becomes locked into the start-up cycle. The compressor turns on and off rapidly, never completing the cooling cycle. This is a huge energy waste (the compressor draws on the most electricity when it starts) and puts so much additional strain on the compressor and motors that it will cause a chain of repair problems and lead to an early replacement.
There are different root causes for short-cycling, and one is an oversized AC. The air conditioner will drop the temperature in the space so quickly that the thermostat will prematurely sense that the cooling cycle is completed and shut down the compressor. It will turn it back on a short time later, and continue to do this. Lowering the thermostat temperature won’t prevent this, since the AC will always cool too fast.
The bottom line is that you must have professionals size your air conditioner so that you have a new cooling system that hits the “Goldilocks Spot”: not too small, not too large, but just right.
Comfort Master Heating & Air Conditioning, Inc. serves Raleigh, NC with air conditioning installation and other HVAC services.