When your HVAC system is running, every bit of cooled or heated air should be making its way into your living spaces—not escaping into the crawl space or attic. But here’s the hard truth: if you’re feeling a nice breeze under your house or in the attic on a 95-degree day, you’ve got a ductwork problem. That’s not comfort—that’s wasted money.

Why Duct Leaks Are a Hidden Problem

Most homeowners don’t think about their duct system because it’s out of sight. But the ducts are just as important as the furnace or air conditioner itself. They’re the “highways” that deliver comfort to your rooms. If those highways have holes, cracks, or loose connections, air slips out before it ever reaches you.

This doesn’t just mean higher utility bills. It also means:

Your system works harder to make up for the loss.

Rooms can feel uneven—some too hot, others too cold.

Indoor air quality can suffer as leaky ducts pull in dust, insulation fibers, or allergens from attics and crawl spaces.

How We Check for Duct Leaks

The good news is you don’t have to wonder whether you’re losing air—you can know for sure. When our technicians perform routine maintenance or a system cleaning, they always visually inspect the duct system. If something looks off, they’ll let you know immediately.

For homeowners who want a more definite answer, we offer a duct pressure test. Here’s how it works:

We hook up a specialized machine to your duct system.

The system is pressurized to measure how much air is escaping.

You can receive a digital reading showing exactly what percentage of air is being lost.

That reading becomes your decision point.

What the Numbers Tell You

Not all duct leaks are severe. For example:

4%–5% air loss – That’s pretty minor. Usually not worth sealing.

20% or more air loss – That’s serious. You’re throwing away a big chunk of your energy bill every month, and sealing is the smart move.

We’ve run tests where the loss was almost nothing. But we’ve also seen tests come back at 20%–24% loss. At that point, homeowners are often shocked at how much money is literally slipping away into crawl spaces and attics.

What Energy Star Says

According to the U.S. Department of Energy’s Energy Star program, the average home loses 20%–30% of conditioned air through duct leaks. Around here, we sometimes see slightly lower numbers because many older homes have duct board instead of metal ducts. Duct board tends to seal better—but it’s still not airtight.

Even at the low end of those numbers, a 20% loss is like throwing away one out of every five dollars you spend on heating and cooling.

Why It’s Worth Fixing

Think about it this way: if you put gas in your car and 20% leaked out before it hit the engine, you’d fix that problem right away. Your HVAC system deserves the same attention.

Duct sealing can:

Lower your utility bills.

Improve comfort throughout the house.

Reduce strain on your HVAC system so it lasts longer.

Keep dirty air from crawl spaces and attics out of your living spaces.

The Bottom Line

If you’re not sure whether your ducts are leaking, stop guessing. A simple duct pressure test can give you a clear, digital reading. Once you see the numbers, the decision is easy—fix it if it’s bad, leave it alone if it’s not.

​At Simmons One Hour Heating & Air Conditioning, we’ve run thousands of these tests for homeowners in Fayetteville, Pinehurst, Laurinburg, Sanford, Lumberton, and surrounding areas. Some homes only lose a little. Others lose a lot. But the key is: you don’t know until you test.