HVAC Maintenance Checklist for Ontario Homes

Heating and cooling equipment is expensive, and small problems left alone become big ones, usually on the coldest or hottest day of the year. Regular maintenance keeps efficiency up, catches safety issues early and is often a condition of the manufacturer's warranty.

This checklist covers what homeowners can safely do and what a qualified technician should check, organized by season for Ontario's climate.

What you can do and what needs a pro

Task	Homeowner	Licensed technician
Replace or clean air filter	Yes	—
Clear snow, leaves and debris from outdoor units	Yes	—
Check and clear condensate drain line	Simple checks	Clean traps, pumps
Vacuum registers and returns	Yes	—
Clean HRV/ERV filters and core	Yes, per manual	Balance airflow
Inspect and clean burners, heat exchanger	No	Yes (gas: TSSA-licensed G2/G1 technician)
Combustion analysis, CO testing	No	Yes
Refrigerant checks or repairs	No	Yes (ODP certification required)
Electrical connections, capacitors	No	Yes

Caution: Never open the burner compartment of a gas furnace or attempt gas line work yourself. In Ontario, gas appliance work must be done by a technician licensed under TSSA rules. If you smell gas, leave the house and call Enbridge Gas (or your gas utility) from outside.

Seasonal checklist

Fall (September–October)

Get your heating system ready before the first cold snap, when service companies are busiest.

Furnace or boiler (gas)

• Book annual service with a TSSA-licensed technician. A full service should include burner cleaning, flame sensor cleaning, heat exchanger inspection, combustion analysis and a carbon monoxide test.
• Replace the filter.
• Check that exhaust and intake vents outside are clear of nests, leaves and debris.
• Test carbon monoxide and smoke alarms; replace batteries.
• Confirm the condensate drain (high-efficiency furnaces) is flowing and not kinked.

Heat pump

• Book service: refrigerant charge check, coil cleaning, electrical connections, defrost control check.
• Confirm the outdoor unit stand is solid and level, with clearance above expected snow depth.
• Check backup heat settings and lockout temperatures on the thermostat. See our cold-climate heat pump guide.

Whole home

• Switch your thermostat schedule to winter settings.
• Open supply registers you closed for summer.
• Clean or replace the HRV/ERV filters.
• Turn off and drain outdoor hose bibs.

Winter (November–March)

• Check the furnace filter monthly; replace every one to three months depending on type and household (pets, renovations).
• After every snowfall, clear snow from around heat pump outdoor units and from furnace and HRV vent terminations on the side of the house. A blocked furnace vent can shut the furnace down.
• Watch for ice building up on or under the heat pump. Light frost that melts during defrost is normal; a solid block of ice is not.
• Keep humidity around 30–40% to avoid condensation on windows. Very cold weather calls for the lower end.
• Note unusual noises, short cycling or cold rooms and call before a breakdown.

Tip: If your heat pump home's winter electricity use jumps suddenly, check whether electric backup strips are running more than they should. A thermostat setting change or a dirty filter is often the cause.

Spring (April–May)

Air conditioner or heat pump

• Book cooling-season service if you have a central AC. Heat pumps serviced in the fall may only need a visual check.
• Remove any winter cover from the AC (heat pumps should never be covered).
• Clear leaves, grass clippings and debris within about 60 cm (2 ft) of the outdoor unit.
• Gently rinse the outdoor coil with a garden hose, power off, from the inside out if accessible. Do not use a pressure washer.
• Confirm the indoor condensate drain and pump work before the first humid day.

Whole home

• Switch thermostat to summer schedule. See our smart thermostats guide.
• Check that dehumidifier drains run freely.

Summer (June–August)

• Check filters monthly during heavy AC use.
• Keep shrubs trimmed back from the outdoor unit.
• Watch for ice on refrigerant lines or the indoor coil (a sign of low airflow or low charge); turn the AC off and call a technician.
• Use blinds and pre-cooling to reduce on-peak demand. See our summer cooling savings guide.

Filters: which one and how often

Filter type	Typical replacement interval	Notes
1-inch fibreglass	Monthly	Protects the equipment, little air cleaning
1-inch pleated (MERV 8–11)	1–3 months	Good everyday choice for most homes
4–5 inch media filter (MERV 11–13)	6–12 months	Larger surface, lower resistance; needs a compatible cabinet
Electronic air cleaner	Wash cells every 1–3 months	Must be kept clean to work

Very high-MERV filters in a 1-inch slot can restrict airflow, especially on heat pumps and variable-speed systems. Ask your technician what your system can handle.

Duct cleaning and maintenance plans

Duct cleaning can be useful after renovations, pest problems or visible mould, but routine duct cleaning has limited proven benefit for energy use. Be wary of very low-priced offers and anyone who arrives at your door. Duct cleaning is one of the services covered by Ontario's ban on unsolicited door-to-door contracts, in effect since 1 March 2018. See our door-to-door scams guide and confirm current consumer protection rules at https://www.ontario.ca (opens in a new tab).

Annual maintenance or protection plans can be worthwhile if they include a full annual service and you value predictable costs. Compare:

• What is included (parts, labour, after-hours calls).
• Whether the plan auto-renews and how prices increase.
• Whether it duplicates coverage in your equipment warranty.

How maintenance affects energy use

A dirty filter, clogged coil or poorly tuned burner can raise energy use noticeably. Exact savings vary by system, but keeping equipment clean and properly adjusted is one of the cheapest ways to protect efficiency. For bigger savings, look at the envelope: see the attic insulation guide and the tips library.

Frequently asked questions

How much does an annual furnace or heat pump service cost?

Typical standalone service visits in Ontario are often in the range of roughly $120–$250, depending on the company and what is included (estimate). Ask for a written list of tasks.

Do I really need annual service if everything works?

For gas appliances, annual service is strongly recommended for safety and is often required to keep warranties valid. For heat pumps and ACs, annual service keeps efficiency up and catches refrigerant or electrical problems early.

Should I cover my air conditioner in winter?

A central AC that does not run in winter can have a breathable top cover to keep debris and ice out. Never cover a heat pump, because it runs in winter and needs full airflow.

How do I know my filter size?

It is printed on the edge of the existing filter (for example 16 × 25 × 1). Write it on the furnace cabinet with a marker so you always have it.