I can’t tell you how many times I’ve been in a customer’s living room, tools in hand, when they ask, “So, what size air conditioner do I actually need?” The answer almost always starts with BTU per square foot — and no, it’s not as complicated as it sounds.
Think of BTUs like horsepower for your cooling system. If you’ve got too little, the AC is huffing and puffing all summer long. Too much, and it’s blasting cold air in short bursts, leaving the place sticky and uncomfortable. Neither is good.
What BTU Per Square Foot Really Means
BTU stands for British Thermal Unit — a fancy way to measure heat. Add “per square foot,” and you’ve got a quick formula for figuring out how much cooling power you need for your space.
Example: a 1,000-square-foot home generally needs around 20,000 BTUs. But here’s the kicker — that’s just a starting point. Ceiling height, insulation, windows, even how much sun hits your home… they all change the number.
The U.S. Department of Energy will tell you the same thing: size matters in HVAC, but accuracy matters more.
Why BTU Per Square Foot Can Make or Break Comfort
Here’s a story. A couple years ago, we replaced a perfectly good AC for a homeowner who thought it was “too weak.” The real problem? Their system was oversized. It cooled the air in minutes but never ran long enough to pull out the humidity. They felt cold and clammy — not exactly the comfort they were paying for.
When you get the BTU per square foot wrong, you either burn money on energy bills or live in a house that never quite feels right.
Figuring Out Your BTU Per Square Foot
The quick math says 20 BTUs per square foot of living space. That means:
1,000 sq. ft. → 20,000 BTUs
1,500 sq. ft. → 30,000 BTUs
2,000 sq. ft. → 40,000 BTUs
But if you’ve got a lot of windows or live somewhere humid, you’ll probably need more cooling power. The U.S. Department of Energy’s guide to room air conditioners explains how to match system capacity to your home’s needs and how factors like climate, shading, and insulation can affect your BTU per square foot requirements.
Other Things That Change BTU Per Square Foot
Climate – Hotter states need more cooling power.
Insulation – Good insulation lowers your needs; bad insulation hikes them up.
People – Bodies put off heat. The more folks in your home, the more BTUs you need.
Windows – Big sunny windows can crank up your cooling requirements.
The Biggest Misunderstanding We See
A lot of folks assume bigger is better. I get it — if one scoop of ice cream is good, three scoops must be better. But in HVAC, oversizing is just as bad as undersizing. An oversized AC never runs long enough to balance the air, so humidity hangs around. Undersized? It runs non-stop, and your energy bills soar.
We’ve had homeowners swear their old unit size was “perfect,” only to find it wasn’t once we checked the actual BTU per square foot after renovations or insulation upgrades.
How We Nail the Right Number
At Summers Comfort Heating & Air, we don’t guess. We take detailed measurements of your home — from the total square footage to how much heat your appliances give off. This careful process ensures your system is sized perfectly for comfort and efficiency.
When to Recheck Your BTU Per Square Foot
It’s worth taking another look if you:
Added or removed rooms
Upgraded insulation or windows
Finished a basement or attic
Little changes can shift the number more than you’d think.
Why Getting It Right Saves You Money
Getting the right BTU per square foot means fewer repairs, longer system life, and lower monthly bills. And let’s be honest — no one’s ever complained about paying less for energy while feeling more comfortable.
Final Thoughts on BTU Per Square Foot
If you remember one thing from all this, let it be this: BTU per square foot isn’t just a number — it’s the foundation of how well your AC will keep you comfortable. Size it right, and you’ll enjoy steady, even cooling without wasting a dime. Size it wrong, and you’ll fight your system every season.
If you’re in Denham Springs or one of the surrounding areas, we’d love to help. Contact Summers Comfort Heating & Air today, and we’ll make sure your home’s cooling feels just right — no guesswork, just reliable results.
