Every July, someone hands us their power bill and asks what's wrong with their AC.
Most of the time, nothing is wrong with their AC.
The AC is doing exactly what it's supposed to do: pulling heat out of the house and dumping it outside. It's just that the house is leaking that heat back in faster than the AC can keep up. So the AC runs and runs and runs, the compressor cycles all day, and the power bill is brutal.
Fixing that bill usually is not about buying a bigger or newer AC first. It's about figuring out where the heat is getting in, where cooled air is being lost, and whether the system is moving the air it was designed to move.
On comfort and efficiency visits in Lehi, Saratoga Springs, and Eagle Mountain, these are the patterns we usually investigate first.
Why does a Utah AC run all day in July?
A Utah AC often runs all day because the home is gaining heat faster than the system can remove it. Attic heat, duct leakage, sunny windows, blocked airflow, dirty filters, and unrealistic thermostat recovery can all make a healthy AC look weak. Start with the building and airflow before assuming the equipment is too small.
Is the attic adding heat to the house?
If your house was built in Utah anytime between 2000 and 2015, there's a very good chance your attic insulation is under-spec for what's actually needed to handle Utah summer heat.
The right target depends on the home, but attic insulation and air sealing are a real cooling issue, not just a winter heating issue. The Department of Energy's air-sealing guidance recommends finding leaks, assessing ventilation needs, and sealing gaps before relying on uncontrolled air leakage.
What we actually check: Go up into your attic (or send us up). Look at insulation depth, disturbed insulation, attic bypasses, recessed lights, bath-fan penetrations, and whether the attic hatch leaks. If the attic is part of the problem, energy-efficiency improvements may help the AC work less hard.
Adding insulation or sealing attic leaks can help, but the scope and payback need to be verified house by house. Treat exact cost and savings claims as quote-specific, not universal.
Are ducts leaking or under-delivering cooled air?
This one shocks people. The ductwork that runs through your attic — the big silver metal or flex duct that carries conditioned air from your furnace/AC to the rooms — is often losing 20-30% of the cooled air through joints, seams, and connections BEFORE it ever reaches a register.
In Utah, attic duct runs matter because they sit outside the conditioned space. The Department of Energy duct guidance says poorly sealed or insulated ducts can contribute to higher energy bills and recommends professional sealing and insulating when ducts are in unconditioned spaces.
We test duct systems with static-pressure and airflow checks. It's not a guess. If the ducts are undersized, leaking, crushed, or poorly balanced, you can have a good AC and still get hot rooms.
What actually fixes it: sometimes mastic sealing, sometimes duct repair, sometimes return-air changes, sometimes balancing. Start with ductwork and airflow diagnostics before replacing equipment.
Either way, the improvement should be measured with better airflow, better room comfort, or shorter run-time pressure on the system.
Are sunny windows driving afternoon heat gain?
If your house has large south-facing or west-facing windows — and a lot of Utah homes do because of the mountain views — those windows are passive solar heaters all afternoon.
The Department of Energy's cooling principles explain the problem simply: sunlight and radiant heat can add real load to a home. If the rooms that struggle are on the west or south side, windows and shade belong in the diagnosis.
Cheap fix: close the blinds or curtains on the sunny side of the house during peak afternoon hours. Sounds obvious but nobody does it. Just doing this can take 3-5 degrees off the upstairs temperature during the worst part of the day.
Better fix: exterior shade, solar screens, or window film where appropriate. The right answer depends on window type, HOA rules, view priorities, and how much heat gain is actually coming through that glass.
Best fix (if you're replacing windows anyway): low-E Argon-filled double-pane windows with a low SHGC rating for the sun-side, higher SHGC for the cold-side. But this is a big-ticket project and only makes sense if you were planning window work anyway.
What thermostat strategy actually helps in July?
There's a lot of conventional wisdom about thermostat settings that actually costs you money.
"Set it higher when you leave the house." Sort of true, but the size and timing of the setback matter. The Department of Energy thermostat guidance supports warmer cooling settings when away and avoiding unnecessary overcooling.
"Don't turn it off, it costs more to cool back down." Completely false. This is a myth. It always costs less to let the house warm up while you're gone than to keep cooling it. The energy you save during the coast-up period is more than the energy spent bringing it back down later.
"Close vents in rooms you don't use." Don't. This was true for old gravity systems. It's false for any modern forced-air system. Closing vents raises static pressure in the ducts, stresses the blower, and usually causes more duct leakage, not less.
What actually works: use the highest comfortable occupied setting, a warmer away setting when the house will be empty long enough for it to matter, and a schedule that avoids forcing the system to recover a large gap during the hottest part of the afternoon. Air Express can review thermostats, AC inspections, and AC maintenance if the schedule cannot hold.
Do ceiling fans lower AC load?
A ceiling fan doesn't cool the air. It cools YOU, by moving air across your skin and increasing evaporative heat loss. This is important because it means:
- A ceiling fan running in an empty room is wasting electricity.
- A ceiling fan running in a room with people in it effectively lowers the "felt" temperature by 4-6 degrees, meaning you can set the thermostat higher without feeling hotter.
- Turn it off when you leave the room. Really.
The Department of Energy fan guidance says ceiling fans can let people raise the thermostat setting by about 4 degrees without reducing comfort. The key is running fans in occupied rooms, not empty ones.
The stuff that matters most, in order.
If you were going to spend money on summer cooling efficiency in order of impact:
- Add attic insulation if you're at R-38 or below. Biggest single improvement, longest payback. ($1,500-3,000)
- Seal your ducts if they're in an unconditioned attic and you've never had them tested. Almost always saves real money. ($500-1,500)
- Add window film or shade to south/west-facing glass in the rooms you cool most. ($200-1,500 depending on scope)
- Upgrade to a smart thermostat with a real away schedule. ($150-300 including install)
- Run ceiling fans in occupied rooms only. (Free if you have them)
Notice what's NOT on this list: replacing your AC. If your AC is under 10 years old and was sized correctly at install, it's almost never the bottleneck. Fix the house first. Then if it's still struggling, talk about the AC.
The free version
If you want to know what's actually causing your July bills, we do a summer efficiency walkthrough. We look at the attic, the ducts, the windows, the thermostat schedule, the AC itself, and give you an honest ranked list of what would actually move the needle.
No upsell. No pressure. Sometimes the answer is "nothing is wrong, your house is just big and Utah is hot." That's fine too — at least then you know.
Official references worth keeping handy: