How often should you service your air conditioner?

Why bother

Keeps it cooling through the worst of summer. This is an essentials-tier job. Skip it and you're inviting the expensive kind of problem, or the dangerous kind.

Why it's a range

Run it flat out all summer in a hot climate and yearly earns its keep; a mild few months and you can stretch it. Once a year before the heat is the safe default.

What the job involves

1. Do the cheap, frequent bits yourself. Swap the filter every 30 to 60 days, monthly if the thing's running flat out all summer. A clogged filter alone makes the system work about 15% harder for the same cool air.
2. Clear the outdoor unit. Rake out the leaves and muck around it, then hose the fins down gently so it can actually shed heat instead of sitting in its own warmth.
3. Book a pro tune-up once a year, in spring before the cooling season starts. They clean the coils, flush the condensate drain, check airflow, tighten the electrical connections, and check the refrigerant, which by law only a certified tech may touch.
4. Listen and watch through the season. Weak airflow, warm air, a creeping bill, or a new rattle all mean something's gone off, and the sooner it's looked at the cheaper it stays.

Do it yourself, or pay someone?

Split job. You can and should do the filter, the coil rinse, and the leaf-clearing yourself. The full tune-up is a pro's, mostly because refrigerant work legally needs an EPA-certified tech: a one-off tune-up runs about $75 to $200, an annual plan roughly $120 to $360.

What skipping it costs

$800 to $2,300 for a compressor replacement, the AC's costliest single part, plus up to roughly 15% higher cooling bills every month a fouled system keeps running. That's the shape of skipping the yearly service: the coils foul, the refrigerant drifts, the connections degrade, and the unit runs hotter and harder until the compressor gives out. The high end is a bigger unit, the low end a small swap, and the wasted electricity you pay either way. A spring tune-up is the cheap end of all that.

Signs it's overdue

• Weak airflow at the vents, or air that comes out warm with the system running and set low. The cool's going somewhere, and it isn't into the room.
• The cooling bill creeps up while you're using the AC the same as ever. Classic dirty coils, low refrigerant, or a compressor starting to labor.
• New banging, rattling, buzzing, or grinding. That's a fan motor, worn bearings, or a belt telling you it's near the end.

When to start thinking about it

This usually means booking someone, so the grumbling starts 28 days ahead to leave time to line it up. Mark it done and Grumpty sets the next one, every 12 months, so you can go back to forgetting it exists.

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