Why Your AC Is Working Overtime This Summer (And Your Ducts Might Be to Blame)
Every July in the Treasure Valley, we get calls from homeowners who are frustrated by the same thing: their air conditioner runs constantly, their energy bills are through the roof, and their house still feels stuffy and uneven, with some rooms cool and others sweltering. They assume their AC is dying. Sometimes it is. But surprisingly often, the real culprit isn’t the unit at all.
It’s the ductwork hiding in your walls, crawlspace, and attic.
What Duct Leakage Actually Is
Your HVAC system is only as effective as the pathway it uses to move air. Conditioned air leaves your AC unit and travels through a network of metal or flexible ducts before it reaches your living spaces. If those ducts have gaps, cracks, loose connections, or deteriorated seals (which is extremely common in homes more than 10 to 15 years old), a significant portion of that cool air never makes it to your rooms.
It escapes into your attic, your walls, or under your crawlspace instead.
Studies from the U.S. Department of Energy suggest that the average home loses 20 to 30 percent of conditioned air through duct leakage. In some older Boise-area homes with original ductwork, that number can be even higher. That means your system might be producing plenty of cool air, but it’s just not getting where it needs to go.
Why Summer Makes It So Much Worse
During a Boise summer, your attic can reach 140 to 150°F on a hot afternoon. When leaky ducts run through that superheated space, two things happen. First, the cool air leaking out heats up instantly and is completely wasted. Second, hot attic air can be pulled back into the duct system through those same gaps, actually warming the air before it reaches your vents.
It’s the equivalent of leaving your refrigerator door cracked open all summer and wondering why your groceries keep spoiling.
The result is a system that runs longer cycles trying to compensate, wears out components faster, and drives your energy costs up, all without ever fixing the root problem.
Signs Your Ducts May Be Leaking
You don’t need to crawl into your attic to suspect a duct problem. Here are some of the most common signs we see in Boise homes:
Uneven temperatures room to room. If your living room is cool but your master bedroom or a back bedroom stays warm no matter what you set the thermostat to, that’s a classic sign that the ducts serving those rooms are leaking or undersized.
Higher-than-expected energy bills. If your utility costs seem out of proportion to how much you’re running your AC, especially compared to previous summers, air loss is a likely contributor.
Rooms that feel stuffy or humid. Leaky ducts can allow unconditioned, humid air from your crawlspace or attic to enter the system. You may notice a musty quality to your indoor air even when the AC is running.
Your AC runs constantly but the house never quite cools down. This is probably the most common complaint. The system isn’t failing; it’s working hard to compensate for what it’s losing.
Visible dust near vents. Excessive dust collecting around supply vents can indicate that your ducts are pulling in debris through gaps or poor connections.
What We Do to Diagnose and Fix It
The good news is that duct leakage is diagnosable and fixable. At Gem Heating & Air Conditioning, when a customer describes symptoms like these, we include a duct inspection as part of our evaluation.
We look at the physical condition of your ductwork, checking for disconnected sections, obvious gaps, deteriorated tape or mastic sealant, and improperly supported flexible duct that may have kinked or collapsed. In some cases we can identify significant losses without specialized equipment just from what we see during a crawlspace or attic inspection.
Depending on what we find, solutions range from sealing accessible joints with professional-grade mastic or metal tape (not the standard gray cloth tape you find at a hardware store, which fails quickly with heat cycling), to repairing or replacing sections of ductwork that are beyond sealing, to recommending a full duct replacement on older systems where the leakage is widespread.
We’ll always give you a straight assessment of what we find and what actually makes sense to do. If your ducts are fine and the problem is somewhere else, we’ll tell you that too.
What About Businesses?
Commercial duct systems are often even more vulnerable to this issue because of their scale and the complexity of the duct runs involved. In a restaurant, retail space, or office building, leaky ducts don’t just affect comfort; they affect your bottom line. We service commercial HVAC systems across the Treasure Valley and can include ductwork assessment as part of your seasonal maintenance.
Don’t Let Summer Drain Your Wallet on a Fixable Problem
If your AC has been running hard this summer without delivering the comfort you expect, don’t assume you need a new unit before someone checks your ductwork. It’s one of the most overlooked sources of HVAC inefficiency, and one of the most correctable.
Give Gem Heating & Air Conditioning a call or text at 208-912-6304. We serve Boise, Meridian, Eagle, Nampa, Caldwell, Kuna, Star, and the surrounding Treasure Valley, seven days a week. We’ll take a real look at what’s going on and give you real options, not a sales pitch.
