We're headed for triple digit heat this weekend, and we already know what the phone's going to do: "My AC won't shut off, is it broken?" Here's the short, reassuring answer for most of you: no. In heat like this, an air conditioner that runs almost constantly is usually doing exactly what it's supposed to. But there's a real line between a healthy system working hard and one that's actually in trouble, and it's worth knowing the difference. Here's how to tell.
Is It Bad That My AC Runs Constantly in the Heat?
Usually not, it's normal. Your AC isn't built to blast cold air in short bursts on a 98-degree day; it's built to run long and steady to keep up. When it's mild out, it cycles on and off. When it's extreme, it may run nearly nonstop just to hold your house where you want it. That's the system doing its job, not a sign it's failing.
Running longer also keeps your temperatures more even and does a better job pulling humidity out of the air. A system that never seems to shut off in a heat wave is often a system that's working exactly right.
How Cool Should My House Actually Be When It's 98 Out?
This is where a lot of the worry comes from. As a rule of thumb, a healthy central AC is designed to keep your home somewhere around 20 degrees cooler than it is outside. So when it's 98, holding your house in the high 70s is your system winning, not falling short.
If you've got the thermostat set to 72 on a 98-degree afternoon and the house is sitting at 78, the AC isn't broken. It's just being asked to do more than any system that size can do on the worst day of the year. Set your expectations to match the weather, and cranking the thermostat down to 65 won't help. It won't cool any faster, it'll just run even longer chasing a number it can't hit.
When Does Constant Running Actually Mean Something's Wrong?
Here's the line. Call it in if you see any of these:
- The air from your vents isn't cold. Running nonstop but blowing room-temperature air points to low refrigerant, a frozen coil, or worse.
- The house is getting warmer, not just holding high. Holding at 78 in a heat wave is fine. Climbing past where it sat yesterday in the same weather means it's losing ground.
- Ice on the unit or the lines. That's a real problem, our post on AC ice walks through it.
- It's short-cycling instead of running long, kicking on and off every few minutes. That's the opposite of steady running, and it usually means an actual fault.
- The breaker keeps tripping. Don't just keep resetting it; that's electrical strain, often a failing part, and worth stopping to check.
- Burning smells or new grinding noises. Shut it off and call.
The theme: long, steady running with cold air coming out is fine. Warm air, ice, short-cycling, or a tripping breaker is not, and running it hard in that state can cook the compressor, which is the last thing you want to replace in July.
What Can I Do to Help It Keep Up?
A few quick things take a real load off the system on the hottest days: close the blinds on the sunny side, change your filter so it can breathe, keep the outdoor unit clear of cottonwood and debris, and don't set the thermostat lower than you actually need.
The Short Version
When it's 98 out, an AC that runs almost constantly and keeps your house in the high 70s is a healthy AC, that's the job. Worry when the air isn't cold, the thermostat is losing ground, you see ice, it's short-cycling, or the breaker's tripping. Everything else is just your system earning its keep in a valley summer.
Stay cool this week. We're a family-run shop covering Nampa, Caldwell, Meridian, Boise, and beyond. 208-455-5158 if something's not right.