7 Mistakes That Can Wreck Your AC (And Cost You Big)

Your AC isn’t invincible. When it’s pushing through triple-digit heat, little mistakes stack up fast. And those mistakes don’t just make the house feel hotter—they can break the system altogether. A busted AC in the middle of summer isn’t cheap to fix, and it’s definitely not fun to deal with. Avoiding these mistakes can save you a lot of money—and a whole lot of stress.

Skipping Filter Changes

When that filter clogs up, airflow tanks. The system has to work harder to push air through, which strains the motor and freezes coils.

A dirty filter isn’t just bad for the air quality—it’s one of the fastest ways to burn out an AC unit. Change it every 30 to 60 days, no excuses.

Blocking Vents

It seems harmless—pushing a couch in front of a vent or closing off rooms you’re not using. But it messes with how your AC balances pressure.

When air can’t circulate right, the system strains to compensate. That drives up your energy bill and can wear out parts way faster than normal.

Ignoring Coil Cleaning

Your outdoor unit sits there collecting dust, pollen, grass clippings, and dirt. When those coils get coated, heat can’t escape properly.

The result? The system overheats and runs longer than it should. Cleaning those coils with a hose a few times a year helps it breathe easier—and last longer.

Forgetting Annual Maintenance

You wouldn’t skip oil changes in your truck and expect it to run forever. Your AC works the same way. No maintenance equals a shorter lifespan.

A pro can catch small problems—like low refrigerant or failing capacitors—before they turn into a dead AC unit in 102-degree weather.

Letting Plants Crowd the Unit

Shrubs, tall grass, or fences too close to the condenser choke airflow. That outdoor unit needs at least two feet of clearance all around.

If it can’t pull enough air in, the compressor runs hotter and longer, which is a fast track to expensive repairs—or a full breakdown.

Cranking It Way Too Low

Setting your thermostat to 65 when it’s 100 outside doesn’t cool your house faster. It only forces the AC to run non-stop until it catches up—or burns out.

Most units are designed to handle about a 20-degree difference from the outside temp. Push it past that too often, and it’s wearing itself out.

Ignoring Drain Line Clogs

That little PVC drain line handles all the moisture your AC pulls from the air. When it clogs, water backs up into the unit or your house.

Worst case? You fry electrical components or flood your ceiling. Flushing the drain line with vinegar every few months keeps it clear and saves a massive headache.

*This article was developed with AI-powered tools and has been carefully reviewed by our editors.