Your Oversized Air Conditioner: Just Too Much of a Good ThingWhile it may seem like an oversized air conditioner represents the best way to stay comfortable during our scorching summers, in reality, it’s not. Our excessive Central Arizona heat does, indeed, factor into the load calculation an HVAC professional will perform to determine the best size A/C, but exceeding the recommended size to cool your home to comfortable levels is actually counterproductive.When a cooling system is too large for a home, it runs in short cycles. It turns on and off frequently, which increases electric bills and reduces indoor comfort. When air conditioners and heat pumps first start, they use more electricity than during the middle of the cycle. The start-up process also increases the amount of wear on all the parts.

According to Salt River Project (SRP), your cooling system should run a minimum of seven to 10 minutes per cycle to reach peak efficiency. During peak efficiency, the system uses less electricity. This amount of running time or longer gives all the conditioned air in your rooms time to mix, which makes you more comfortable.

It’s also enough time for the evaporator coil inside the air handler to get cold enough to remove excessive humidity from your air. Although our region is normally dry, the humidity does come up during July and August. Having an oversized air conditioner will make your home feel warmer because extra humidity stays behind, making you feel warmer.

What water vapor does condense may sit in the drain pan inside the air handler and evaporate back into your home instead of accumulating a sufficient amount to drain outdoors. Excessive humidity indoors also promotes mold growth, which can be a serious problem if it’s black mold, a strain that causes serious health problems.

The best way to avoid too large a cooling system is to work closely with your HVAC contractor on performing a cooling load calculation before installing your next system. If you’d like more information about an oversized air conditioner, contact our pros at Wolff MechanicalWe’ve provided quality HVAC services for homeowners in the greater Phoenix area for more than 20 years.

Our goal is to help educate our customers in the Phoenix Valley area of Arizona about energy and home comfort issues (specific to HVAC systems). 

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