AC running but not cooling: what it points to, what it costs

Match the symptom to the likely fault

Each pattern sends a technician to a different part of the system, so the one you describe narrows the list before the visit:

• Outdoor unit hums, fan still. Points to the capacitor, the contactor or the condenser fan motor.
• Outdoor unit silent, indoor fan blowing. The outdoor side gets no signal or no power: thermostat wiring, a contactor, a disconnect.
• Both running, air only slightly cool. Low refrigerant, a dirty coil or weak airflow.
• Frost on the copper line or the indoor coil. Can come from restricted airflow or a low charge.

For a wall head that blows room-temperature air, see ductless mini-splits; for an AC that has stopped altogether, see AC repair.

Refrigerant: in Ontario, the leak test comes first

Ontario’s O. Reg. 463/10 covers home air conditioners and heat pumps. Under it:

• Only a person certified under the regulation may service or test the unit, and that person or the employer must have equipment to recover the refrigerant.
• A leak test follows the environmental code of practice named in the regulation, and the technician must tell you the result.
• After the test, a notice goes on the unit: date, technician’s name, certificate number and expiry, the result, and, if there is a leak, a statement that nobody may add refrigerant until it is repaired.
• A refill is allowed when that notice is at most six months old, shows no leaks, and the unit shows no damage that could let refrigerant escape.

Leak detection runs $100–$300 on a Canada-wide guide. Keep a photo of the notice.

Older units on R-22

Federal regulations prohibit making or importing products that contain or are designed to contain HCFC-22, the refrigerant sold as R-22. Older systems still run on it; newer ones use R-410A or R-32, HomeStars notes. The same guide puts R-22 at $100–$200 a pound or more and a recharge on such a system at $400–$800. If your outdoor unit’s rating plate says R-22, say so in the request; it changes the conversation from a refill to repair or replace.

Hot afternoons and utility programs

Save on Energy’s Peak Perks program pays households to let it adjust a Wi-Fi smart thermostat on central air or a central heat pump. On the hottest non-holiday weekday afternoons, the setting can rise up to 2°C for no more than three hours. You are notified first and can override it. A house that runs warm only then may have a working AC and an active event.

What the quote should spell out

A useful written quote separates:

• the call-out or diagnostic fee ($75–$150 on a Canada-wide guide) and the hourly rate if the job runs long ($75–$150; after-hours $150–$250);
• the fault found and how it was confirmed;
• the part price and the labour, each on its own line;
• the refrigerant type, the pounds added and the rate per pound;
• the leak-test result, and the leak repair as its own item;
• HST.

Two quotes compare only when they name the same fault and the same fix.

When the compressor is the fault

On a Canada-wide guide, a compressor runs $1,300–$2,500. HomeStars’ Ottawa guide shows a new central air system at $3,000–$7,500 installed. The same source suggests a rule of thumb: when a repair quote passes half the cost of a new installed system, replacement usually makes more sense, and on an older unit one failing part often means others are close behind.

With the cooling season over, there is time for a second quote. See the Ottawa AC repair cost guide for more ranges.

Who takes your request

Ottawa Heating Desk is a request service and does no repairs itself. Your request goes to one independent Ottawa heating and cooling company. That company calls you, diagnoses the AC, prices the repair and does the work.