It's hot, your AC is running, but your house isn't getting cool. Before you call for an expensive service call, there are several things you can check yourself.
Here's a troubleshooting guide that covers the most common reasons an AC stops cooling properly - from simple fixes to signs you need a professional.
Check These First (Free Fixes)
1. Thermostat settings - Is it set to COOL (not heat or fan only)? - Is the temperature set below current room temp? - Are batteries dead? (if battery-powered)
2. Air filter - A clogged filter is the #1 cause of poor cooling - Check filter - can you see light through it? - Replace if dirty (every 1-3 months in summer)
3. Vents and returns - Are supply vents open and unobstructed? - Is furniture blocking return air vents? - Are any vents closed that shouldn't be?
4. Outdoor unit - Is the outdoor unit running? - Is it blocked by debris, leaves, or plants? - Has grass grown up around it?
5. Circuit breakers - Check both indoor and outdoor breakers - Reset if tripped (but note if it trips again)
Common Causes You Can Identify
Frozen evaporator coil - Signs: Ice on refrigerant lines, weak airflow - Cause: Low airflow (dirty filter) or low refrigerant - Temporary fix: Turn off AC, run fan only to thaw - If it refreezes: Call a technician
Dirty condenser coils (outdoor) - Signs: AC runs but doesn't cool well - Check: Look at outdoor unit - coils covered in debris? - Fix: Gently hose off coils (when unit is off)
Refrigerant leak - Signs: Gradual cooling loss, ice buildup, hissing sound - This requires professional repair - Don't let anyone just "top up" refrigerant - find the leak
Failing compressor - Signs: Outdoor unit hums but fan doesn't spin - This is expensive to repair ($1,500-$2,500) - Often means replacement is better option
When to Call a Professional
Call immediately if: - You smell burning or see smoke - Breaker keeps tripping - You hear grinding or screeching - There's water leaking inside - Ice won't stop forming
Schedule service if: - Basic troubleshooting didn't help - AC runs but never reaches set temperature - Some rooms cool, others don't - Energy bills suddenly spiked - AC short-cycles (turns on/off frequently)
What to tell the technician: - When the problem started - What you've already checked - Any unusual sounds or smells - When AC was last serviced
Realistic Repair Costs
Minor repairs: - Capacitor replacement: $150 - $300 - Contactor replacement: $150 - $300 - Refrigerant recharge: $200 - $400 - Fan motor: $300 - $600
Major repairs: - Compressor: $1,500 - $2,500 - Evaporator coil: $1,000 - $2,000 - Condenser coil: $1,000 - $2,500
When repair doesn't make sense: - AC is 12+ years old - Repair exceeds 50% of replacement cost - Uses R-22 refrigerant (phased out) - Multiple component failures
Prevention for Next Time
Prevent future cooling problems:
- Change filter monthly during summer
- Annual maintenance - have AC serviced in spring
- Keep outdoor unit clear - 2 feet clearance on all sides
- Don't close too many vents - system needs airflow
- Use a programmable thermostat - avoid temperature swings
- Check condensate drain - clear clogs before they cause problems
Signs your AC needs maintenance: - Cooling takes longer than usual - Utility bills increasing - More dust in the house - Unusual sounds when running
The Bottom Line
Start with the basics - filter, thermostat, vents - before calling for service. Many AC problems have simple solutions. But if you've checked everything and it's still not cooling, don't wait - the problem will only get worse in the heat.
Need help? We offer same-day emergency AC service throughout Ottawa during summer months.
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