It’s 28°C, the AC is running, the fan is spinning, but the house just keeps getting warmer. Before you panic-call anyone — or get talked into a $3,000 replacement — there are three quick things worth checking yourself. They solve a surprising share of "not cooling" calls in five minutes.
Three things to check before calling
1. Is the thermostat actually set to cool?
It sounds obvious, and it happens more than you’d guess. Some smart thermostats also have a "fan only" mode that looks like cooling but isn’t — the fan just blows room-temperature air around. Confirm the mode is set to Cool, the fan is on Auto (not On), and the setpoint is at least 3°C below the current room temperature. If someone else in the house nudged it, that can be the whole problem.
2. Is the air filter clogged?
Your AC pulls air through the same filter your furnace uses. When it’s clogged, airflow across the indoor coil drops — and with AC that’s worse than it sounds, because the coil can freeze into a solid block of ice and stop moving any air at all. Pull the filter and hold it up to a light. If you can’t see through it, replace it with the same size and MERV rating, and give the system time to thaw before running it again.
3. Is the outdoor unit covered in debris?
Grass clippings, cottonwood fluff, leaves, and dog fur all collect on the outdoor condenser — and that unit needs clear airflow on every side to dump heat outside. If half of it is matted over, it can run all day without cooling your home. Shut the system off and rinse the fins gently with a garden hose (never a pressure washer), and keep at least a foot of clearance around the unit.
When to call us right away
If the AC is iced over, making strange noises, or tripping breakers — stop running it and call. Continuing to run a struggling AC can turn a $200 repair into a $2,000 compressor replacement.
Those symptoms usually point to low refrigerant, a failing capacitor, or an electrical fault — and they sit on the other side of the line from do-it-yourself. They involve sealed refrigerant systems and live electrical components that need a licensed technician and the right tools to handle safely.
What an honest diagnostic looks like
When we look at an AC that isn’t cooling, we measure refrigerant pressures, test the electrical components, check the coils and airflow, and then write up exactly what we found and quote the repair before doing it — $169+tax flat rate. We don’t recommend replacement unless the unit is genuinely past end-of-life. If someone quoted you a $4,000 new system after a ten-minute look, get a second opinion.