Window AC Size Calculator

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FAQ: Sizing Your Window AC Unit

What is an AC Unit ton?

It’s a way of measuring cooling capacity: 1 AC unit ton = 12,000 BTU per hour. So when someone says a “2 ton AC unit,” they mean it can remove about 24,000 BTU of heat per hour.

How do I convert BTU from the calculator into AC unit tons?

Take the BTU result from your AC size calculator and divide by 12,000. For example, if the calculator says 10,000 BTU, that’s about 0.8 ac unit ton, and you’d typically round to a 1-ton AC unit.

Why does ceiling height matter for AC sizing?

It’s because your AC is cooling the volume of air, not just the floor area. Taller ceilings mean more cubic feet of air, so you need more BTUs than you would for the same floor area with a standard 8-foot ceiling.

Why can an oversized AC be a bad thing?

It’s because an oversized unit cools the air too quickly and then shuts off before it can remove enough humidity. That short cycling wastes energy, feels clammy instead of comfortable, and can wear the unit out faster.

Is a bigger ac unit ton always better?

No. An oversized ac unit ton rating can cool the air too fast and shut off before it removes enough humidity. That short cycling wastes energy and feels clammy, so it’s better to match the AC unit ton closely to the calculator’s BTU recommendation.

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