What Size AC Do You Actually Need? (Hint: Probably Smaller Than You Think)

When buying a new AC, most homeowners assume bigger is better. A 5-ton unit must be better than a 3-ton unit, right? Wrong. An oversized AC is one of the worst things you can do to your home.

The Short Cycling Problem

An oversized AC cools the house down too quickly. It blasts cold air, hits the target temperature in 5 minutes, and shuts off. This is called 'short cycling.' Because the system turns on and off constantly, it burns out the compressor years before its time.

The Humidity Nightmare

An AC doesn't just lower temperature; it removes humidity. But it takes about 15 minutes of continuous running for an AC to start pulling significant moisture out of the air. If your oversized system shuts off after 5 minutes, it never dehumidifies the house. You end up with a home that is 70 degrees but feels like a damp cave.

The Manual J Solution

The only way to properly size an AC is a 'Manual J Load Calculation.' This factors in your square footage, insulation, window types, roof color, and home orientation. If a contractor just looks at your old unit and says 'let's go a half-ton bigger just to be safe,' show them the door.