The air conditioner is running. It’s been running basically nonstop for three days. The house is still warm. First instinct is usually that something is wrong with the unit itself.
Sometimes that’s true. But before calling an HVAC tech, check the attic. Temperatures up there in a Texas summer can hit 150 degrees. When attic insulation isn’t doing its job, that heat moves straight down into the living space and your AC is fighting it all day. Fixing the insulation is often what actually solves a “the house won’t cool down” situation, and it’s a lot less expensive than a new HVAC system.
Texas Uses Insulation Harder Than Most Places
Most of the country has a cooling season that lasts two or three months. San Antonio and Austin run AC from roughly April through October, sometimes longer. Six or seven months of continuous thermal load on the ceiling system every year.
The Department of Energy recommends R-38 to R-60 for attics in Texas’s climate zone. A lot of older homes in this area, especially anything built before 2000, were installed to standards that don’t come close to that. The insulation was up to code when it was put in. The code just didn’t reflect what we now know about what this climate actually requires.
If your home has never had an insulation evaluation and it’s more than 15 or 20 years old, there’s a decent chance you’re paying for that gap every single month.
Blown-In vs. Spray Foam: Which Makes Sense
Blown-in loose-fill is the most common upgrade for existing homes. The material gets blown in through a hose and covers the attic floor, filling around obstacles and into corners more completely than batt insulation can. It’s cost-effective and works well for most applications. Adding a layer of blown-in on top of what’s there is often all it takes to bring an older home up to current R-value targets.
Spray foam is a different approach entirely. Instead of the attic floor, it goes on the underside of the roof deck. This pulls the attic inside the thermal envelope of the house. Air infiltration drops significantly. It’s more expensive, sometimes considerably so, but it performs at a higher level and is especially effective on older homes with significant air leakage or any home where HVAC ducts run through unconditioned attic space.
This Affects Your Roof Too, Not Just Your Energy Bill
Poor attic insulation doesn’t just make the AC work harder. It shortens the life of the roof itself. Heat trapped in the attic bakes the underside of the deck, which degrades shingles from below and can warp decking over time, especially on south-facing sections that get direct afternoon sun for months.
Proper insulation paired with proper ventilation keeps the attic at a manageable temperature year round, which protects the structure above it. If a roof replacement is coming up in the next year or two, doing the insulation and ventilation work at the same time is the smart call.
Atrium Roofing handles attic insulation as part of its residential roofing work in both San Antonio and Austin. They include a ventilation check on every insulation project because the two systems are connected. Upgrading insulation without addressing ventilation tends to leave problems on the table.
How to Know if Yours Is the Problem
Energy bills climbing for no clear reason. Upper-floor rooms that are noticeably harder to cool than rooms below. Hot spots on ceilings that seem to radiate heat into the room.
In the attic: insulation that’s been compressed down to a couple of inches is doing almost nothing. Old fiberglass batts that got soaked from a past leak have lost their effective R-value. And any insulation that’s visibly wet, moldy, or damaged needs to come out before anything new goes in. Adding new material on top of a compromised layer buries the problem temporarily and makes it harder to find later.