AC size is measured in tons. A ton isn't weight. It's how much heat the system can pull out of your house in an hour. Most homes here have somewhere between 2 and 5 tons.
Why not just go bigger?
Because a system that's too big cools the house too fast. That sounds nice, but the AC also has to pull water out of the air, and it can only do that while it runs. A big system hits the temperature in a few minutes and shuts off before it gets the moisture out. The result: a cold, clammy house. In South Louisiana, that's a big deal.
An oversized system also turns on and off a lot, which wears it out faster.
And too small?
A system that's too small runs all day in July and never catches up. Your bill goes up and the house stays warm.
What actually decides the size
- Square footage, but only as a starting point
- Insulation in the attic and walls
- Windows: how many, how big, and which way they face
- Sun and shade: a west-facing house in full sun needs more than one under big oaks
- Ceiling height and how many stories
- Ductwork: leaky or undersized ducts can make any system look too small
- How many people live there and what's in the house
Why the old size might be wrong
A lot of replacements just match whatever size was there before. But if that system was sized wrong, or you've added insulation, new windows, or a room since, the old size may not fit anymore.
What we do
At a free estimate, we measure the house and look at insulation, windows, and ductwork before we recommend a size. Then you'll see your options side by side, in writing. See how installation works.