A Season-by-Season Maintenance Checklist

What homeowners can reasonably do themselves

• Check and replace or clean furnace, air handler, and ductless indoor unit filters on the schedule recommended by the manufacturer.
• Clear leaves, snow, and debris from around an outdoor heat pump or air conditioner unit, keeping vents unobstructed.
• Confirm the thermostat is set correctly, has fresh batteries if applicable, and that any programmed schedule matches your actual routine.
• Check that a visible condensate drain line is not obviously blocked or leaking, and wipe away visible dust from accessible vents and registers.

What must be left to a qualified technician

• Anything involving refrigerant, including checking charge level, searching for leaks, or recovering and recharging refrigerant.
• Any electrical work, including inspecting or servicing circuits, breakers, capacitors, or wiring connections.
• Burner inspection, cleaning, or adjustment on any furnace or combustion appliance.
• Opening sealed components, such as a compressor housing or a sealed coil compartment.
• This work requires training, certification (including halocarbon handling certification for refrigerant), and proper tools, and attempting it without those can be unsafe and can void warranties.

Fall checklist, before heating season

• Owner: replace or clean furnace and heat pump filters.
• Owner: clear debris from around the outdoor heat pump unit.
• Technician: annual furnace or heat pump inspection and combustion safety check, if applicable.
• Technician: verify refrigerant charge and electrical connections on a heat pump before the heating season begins.

Winter checklist

• Owner: keep snow and ice cleared from around the outdoor unit after storms, without chipping at the coil or fins.
• Owner: watch for unusual noises, reduced airflow, or a unit that seems to run constantly without keeping up.
• Technician: address any ice buildup on the outdoor unit that does not clear during normal defrost cycles, since this can indicate a mechanical issue.
• Technician: any furnace short-cycling, burner odour, or carbon monoxide alarm should be treated as urgent and referred to a professional immediately.

Spring checklist, before cooling season

• Owner: replace or clean filters after a winter of heavy use.
• Owner: clear the area around the outdoor condenser once snow has melted.
• Technician: pre-season air conditioner or heat pump check, including verifying refrigerant charge and cleaning the outdoor coil.
• Technician: inspect the condensate drain system beyond what is visible, and clear any internal blockage.

Summer checklist

• Owner: check filters more frequently during heavy cooling use, since dust accumulates faster with more airflow.
• Owner: confirm the outdoor unit has clear airflow on all sides and is not shaded by overgrown vegetation.
• Technician: address any cooling capacity complaints, ice on the indoor coil, or unusual sounds promptly rather than waiting for a scheduled visit.

Ventilation equipment (HRV/ERV) notes

• Owner: clean or replace HRV/ERV filters on the manufacturer's schedule, generally more often than furnace filters.
• Owner: check exterior intake and exhaust hoods for obstruction by snow, leaves, or insect nests.
• Technician: core cleaning, balancing airflow between rooms, and inspecting the condensate drain on ventilation equipment.

When to call sooner than the schedule suggests

A checklist assumes normal operation. If you notice a burning smell, water pooling near equipment, a breaker that trips repeatedly, a carbon monoxide alarm, or a system that stops responding to the thermostat entirely, do not wait for the next seasonal check. These situations call for a technician promptly rather than a homeowner attempting to diagnose or work around the problem.