AC not cooling? Try these 5 checks first

It's the first hot day of the season. The AC is running, but the house isn't getting cool. Before you book a service call (and pay for a diagnostic), walk through these five quick checks. About a third of "my AC is broken" calls we run in May and June turn out to be one of these — and you can fix them yourself in under five minutes.

1. Check the thermostat is set to COOL — not just ON

Sounds dumb. Happens constantly. Smart thermostats and programmable thermostats can drop into "fan only" or "heat" mode after a power blip, a software update, or a curious kid pressing buttons. Confirm:

• Mode is set to COOL
• Set point is at least 4°F below room temperature
• Fan is set to AUTO, not ON (ON runs the blower constantly even when there's no cooling, which can feel warm and humid)

2. Check (and probably replace) the air filter

If your filter looks like a piece of gray felt, your AC is choking. A clogged filter restricts airflow so badly that the indoor coil can freeze into a solid block of ice — at which point cool air stops coming out of the registers entirely.

3. Look at the outdoor unit

Walk outside to your condenser (the big metal box humming in the yard). Two things to check:

• Is the fan on top spinning? If the unit is humming but the fan isn't moving, kill the power at the disconnect and call us — that's usually a capacitor or motor.
• Is the coil clean? Cottonwood fluff, grass clippings, and leaves can clog the outside of the unit. Power it off, gently rinse from the inside out with a garden hose at low pressure. Don't use a pressure washer — you'll bend the fins.

4. Check the breakers and the disconnect

An AC system has at least two breakers in the main panel (one for the indoor air handler, one for the outdoor condenser) plus a pull-out disconnect right next to the outdoor unit. A breaker that's been tripped will look slightly out of line with its neighbors. Flip it firmly OFF, then ON. If it trips again right away, stop and call us — something's drawing too much current.

5. Check the condensate drain and float switch

Modern AC systems have a small safety switch on the condensate drain pan that will shut the whole system off if the drain backs up. Look at the indoor unit — usually in the basement, attic, or a closet. If you see standing water in the pan or a soggy ceiling stain below it, the drain is clogged. We can clear it in 15 minutes, but it's a real call, not a quick fix.

If you've checked all five and it's still warm

Now it's a real service call — and that's what we're here for. Most likely culprits at this point: low refrigerant (a leak somewhere), a failing capacitor, a frozen evaporator coil that needs to thaw and be diagnosed, or a contactor that's burned out. None of these are DIY fixes.