Air Conditioner Not Cooling: Who Should You Call?
Urgency: SoonUpdated 2026-08-31
Short answer
Replace the furnace filter, clear debris from the outdoor condenser, and check that the breaker for the outdoor unit has not tripped. If the system runs but the air is not cold, or the indoor coil is iced over, call a licensed HVAC technician — that usually means low refrigerant or a failed compressor, neither of which is DIY territory.
Who to call: A licensed HVAC technician — refrigerant handling requires certification.
What to do right now
- 1Set the thermostat to Cool and the fan to Auto, not On.
- 2Replace a dirty furnace filter — restricted airflow is the leading cause of a frozen coil.
- 3Clear leaves, grass and shrubs to at least 60 cm around the outdoor unit.
- 4If the coil or line is iced, shut the AC off and run the fan alone for a few hours to thaw it.
Most likely causes
- Dirty filter or blocked airflow
- Starves the coil, freezes it, and cooling stops entirely.
- Low refrigerant from a leak
- Air conditioners do not consume refrigerant. If it is low, there is a leak that needs finding, not just a top-up.
- Failed capacitor or contactor
- The outdoor fan hums but does not spin — a common and relatively inexpensive repair.
- Dirty condenser coil
- Cottonwood fluff and dust blanket the coil and stop it rejecting heat.
What it typically costs in the GTA
$120–$180 diagnostic. $200–$400 for a capacitor or contactor. $500–$1,500 for a refrigerant leak repair and recharge. $4,000–$8,000 for a new system installed in the GTA.
Ranges are typical market pricing for the Greater Toronto Area and vary with access, age of the home, and time of year. Always get the scope in writing before work starts.
Why 'just add refrigerant' is the wrong answer
A sealed system does not use up refrigerant. A technician who tops it up without finding the leak is selling you the same repair again next summer. Ask for the leak location to be identified and documented.
Book maintenance in spring, not July
During a GTA heat wave, HVAC companies triage and wait times stretch. A spring tune-up catches weak capacitors and dirty coils before the first 32°C day.
Get the right pro on it
Describe the problem in your own words. We’ll work out which trade you need and connect you with suitable local pros. Free, no obligation.
Frequently asked questions
- How cold should the air from the vents be?
- Roughly 8–12°C cooler than the air going into the return. Much less than that suggests a refrigerant or airflow problem.
- Why is my AC freezing up?
- Almost always restricted airflow — a dirty filter, closed vents, or a failing blower — or low refrigerant.
- Should I repair or replace a 15-year-old AC?
- At fifteen-plus years, especially with R-22 refrigerant, replacement usually wins on both reliability and running cost.