Why Isn’t My Air Conditioner Working? Common Problems & Simple Fixes for Homeowners

There’s nothing worse than your air conditioner giving up on a hot summer day—especially in the middle of a heatwave. Before you call for professional help, there are a few simple things you can check on your own. Many common AC issues can be resolved with quick, easy fixes that don't require tools or technical know-how.

Here’s a guide to help you identify why your AC might not be working and what you can do about it as a homeowner.

1. Thermostat Troubles

Problem: The thermostat isn’t set correctly, or the batteries are dead.

Fix:

• Make sure the thermostat is set to "Cool" and the temperature is set lower than the current room temperature.

• Replace the batteries if the screen is blank or unresponsive.

• Double-check the settings—some thermostats can be accidentally switched to “Heat” or “Fan Only” mode.

✅ Pro tip: Try lowering the thermostat by 5 degrees and wait a few minutes to see if the system kicks in.

2. Dirty Air Filter

Problem: A clogged or dirty air filter is blocking airflow.

Fix:

• Check the air filter, usually located behind the return vent or inside the furnace/air handler.

• If it looks dusty or gray, replace it. Most filters should be changed every 1–3 months, depending on use and air quality.

✅ Pro tip: A clean filter helps your system run more efficiently and prevents long-term damage.

3. Tripped Circuit Breaker

Problem: A blown fuse or tripped breaker is cutting off power to the AC unit.

Fix:

• Go to your electrical panel and check for any tripped breakers. If the AC breaker is off, flip it back on.

• If it trips again immediately, don’t force it—call a professional.

✅ Pro tip: Label your breakers so you can easily find the one for your AC in the future.

4. Blocked Outdoor Unit

Problem: The outdoor condenser unit is covered in dirt, leaves, or debris, restricting airflow.

Fix:

• Gently clean around the outdoor unit—remove leaves, grass clippings, or anything that might be blocking the airflow.

• Make sure there’s at least 2 feet of clearance on all sides.

✅ Pro tip: Turn off power before cleaning to stay safe, and avoid spraying water directly into the electrical components.

5. Frozen Evaporator Coil

Problem: Ice buildup on the indoor coil is stopping your AC from working properly.

Signs: Reduced airflow, warm air from vents, or visible ice on the indoor unit.

Fix:

• Turn the system off and set the thermostat to “Fan Only” to help it defrost.

• Check your air filter and replace it if needed—it’s a common cause of freezing.

• If the coil keeps freezing, call an HVAC pro—it may be a refrigerant issue.

✅ Pro tip: Never try to chip away the ice. Let it melt naturally.

6. No Power to the Outdoor Unit

Problem: The disconnect switch near the outdoor unit is off, or a fuse has blown.

Fix:

• Look for a power switch or disconnect box near the outdoor condenser. Make sure it’s on.

• If the system still doesn’t run, you may need to replace a fuse—but that’s best left to a professional.

When to Call a Pro

If you’ve tried these simple fixes and your AC still isn’t working, it’s time to call in an HVAC technician. There could be a more serious issue like:

• Low refrigerant levels (usually from a leak)

• A faulty capacitor or compressor

• Electrical or wiring problems

• A failed thermostat

Final Thoughts

Many AC issues can be solved with a bit of basic troubleshooting, saving you time and money. Regular maintenance—like changing your air filter and keeping the outdoor unit clean—can also prevent future breakdowns.

But when in doubt, don’t guess. If your AC isn’t working after trying the tips above, reach out to a trusted HVAC professional to avoid further damage or higher repair costs.

Need help diagnosing your AC issue in the GTA? Contact +1(289)-306-0542 for fast, reliable service—we’ll help you beat the heat and stay comfortable all summer long.