It happens every summer without fail. The temperature hits 32°C, you turn on your air conditioner — and nothing happens. Or worse, it runs but blows warm air. Or it trips the breaker the moment it kicks on.
You're not alone. AC failures spike dramatically during heat waves because systems that have been sitting idle run harder than ever, revealing problems that were lurking all along.
Here's what's most likely wrong — and what to do about it.
Most Common Reasons AC Fails in Hot Weather
1. Dirty or Clogged Air Filter
This is the number one cause of AC problems and the easiest to fix. A clogged filter restricts airflow so severely that the system overheats and shuts down. Check your filter first — if it's grey and thick with dust, replace it immediately. Filters should be changed every 1-3 months.
2. Low Refrigerant (Freon Leak)
If your system blows air but it's not cold, you're likely low on refrigerant. This happens when there's a slow leak in the system. Refrigerant doesn't "run out" — if it's low, there's a leak that needs to be found and repaired by a licensed technician before recharging.
3. Frozen Evaporator Coil
Ironically, your AC can freeze up in summer. If airflow is restricted (see: dirty filter) the evaporator coil gets too cold and ice forms around it. Turn the system off, let it thaw for 2-3 hours, replace the filter, then try again. If it keeps freezing, call a technician.
4. Tripped Circuit Breaker
During a heat wave, your AC runs longer and harder than normal. This can trip a circuit breaker — especially in older homes. Check your electrical panel. If the breaker keeps tripping, don't keep resetting it. A repeatedly tripping breaker signals a deeper electrical or mechanical problem.
5. Condenser Unit Blocked or Dirty
The outdoor unit (condenser) needs airflow to release heat. If it's surrounded by overgrown plants, fencing, or built up with debris from winter, it can't do its job. Clear at least two feet of space around the unit and gently rinse the fins with a garden hose.
6. The System Is Simply Too Old
HVAC systems have a lifespan. If your AC is 12-15 years old and failing during a heat wave, repairs may just be delaying the inevitable. A new high-efficiency heat pump will cost less to run, qualify for BC rebates, and give you reliable cooling for the next 15+ years.
What To Do Right Now
- Check and replace the air filter
- Check the circuit breaker
- Clear space around your outdoor unit
- Turn the system to fan-only for 2 hours to let it reset
- If none of that works — call a technician
When to Call Grove Mechanical
If your system still isn't working after the steps above, you need a licensed technician to diagnose the problem. Grove Mechanical offers same-day service calls across Metro Vancouver and the Fraser Valley. We carry refrigerant, replacement parts, and can assess whether repair or replacement makes more sense for your situation.