Seasonal HVAC Maintenance Checklist for Every Time of Year

Heating and cooling systems tend to fail on the coldest night or the hottest afternoon, which is also when every HVAC company in town is booked. Regular maintenance will not prevent every breakdown, but it catches many small problems early, helps the system run efficiently, and gives you a better chance of getting through peak season without an emergency call.

This checklist is organized by season. Some tasks are easy for any homeowner; others belong to a licensed technician. Always follow your equipment manufacturer's instructions, and turn the power off at the thermostat and the system's disconnect before you touch anything inside a unit.

Year-round basics

• Check the air filter regularly. A clogged filter makes the system work harder and can reduce comfort. Many manufacturers suggest checking monthly and replacing every one to three months, more often with pets, allergies or construction dust. Follow the guidance for your filter and system.
• Keep vents and returns clear. Furniture, rugs and curtains blocking supply vents or return grilles restrict airflow.
• Test smoke and carbon monoxide detectors. If you have any fuel-burning appliance (gas furnace, boiler, water heater, fireplace) or an attached garage, working CO detectors are essential.
• Watch for changes. New noises, odd smells, short cycling, uneven temperatures between rooms, or a sudden jump in your energy bill are all worth a closer look.

Fall: get heating ready

Fall is the best time to schedule a heating tune-up, before the first cold snap creates a rush.

What you can do

• Replace the air filter.
• Run the heat for a few minutes on a mild day to make sure it works. A brief dusty smell the first time is common; a smell that persists is not.
• Clear storage boxes and clutter away from the furnace, boiler or air handler.
• If you have a heat pump, clear leaves and debris from around the outdoor unit.
• Check that exhaust vents and flues outside the house are not blocked by leaves, nests or debris.
• Bleed radiators if you have a hot-water system and you are comfortable doing so.

What a technician typically checks

• Burners, flame and ignition on gas systems.
• Heat exchanger condition.
• Venting and draft, including carbon monoxide safety.
• Electrical connections, controls and safety switches.
• Blower motor and belt.
• Thermostat operation.

Winter: keep it running

• Keep the outdoor heat pump unit clear of snow and ice. Never chip ice off the coils with a sharp tool.
• Keep checking the filter; systems run longest in winter.
• Make sure outdoor vents for high-efficiency furnaces are not buried by snow.
• Know where your system's power switch and gas shutoff are.
• If the heat stops working, check the thermostat batteries and settings, the breaker, and the furnace power switch before you call. Many service calls turn out to be one of these.

If you smell gas, do not try to find the source. Leave the house and call your gas utility or 911 from outside.

Spring: get cooling ready

Spring is the time for an air conditioning or heat pump tune-up, again ahead of the rush.

What you can do

• Replace the air filter.
• Clear at least a couple of feet around the outdoor condenser: leaves, grass clippings, weeds and anything stored against it. Trim back shrubs.
• With the power off, gently rinse the outside of the condenser coil with a garden hose if the manufacturer allows it. Do not use a pressure washer, which can bend the fins.
• Check that the condensate drain line near the indoor unit is not clogged.
• Test the AC on a mild day before you actually need it.

What a technician typically checks

• Refrigerant levels and signs of leaks. In the US, technicians who handle refrigerant must be certified by the EPA, so this is not a do-it-yourself job.
• Coil condition, indoor and outdoor.
• Capacitors, contactors and electrical connections.
• Condensate drain and pan.
• Airflow and temperature difference across the coil.

Summer: keep it efficient

• Keep the outdoor unit clear and shaded from debris (but never enclosed).
• Check the filter more often during heavy use.
• Use blinds and curtains on sun-facing windows during the hottest part of the day.
• If the system runs constantly without cooling, or you see ice on the refrigerant lines, turn it off and call a technician. Running it frozen can cause more damage.
• Watch for water around the indoor unit, a sign of a clogged drain.

Signs you should call a pro now

• Your carbon monoxide detector goes off.
• You smell gas or a burning electrical smell.
• The system trips the breaker repeatedly.
• Loud banging, grinding or screeching.
• Water leaking from the furnace or air handler.
• The system turns on and off every few minutes.

Choosing an HVAC company

When you hire for maintenance or repair, ask:

• Are you licensed for HVAC work in this state? Licensing varies by state; check with your state licensing board.
• Are your technicians EPA certified for refrigerant handling?
• Are you insured?
• What exactly does your tune-up include?
• Do you offer a maintenance plan, and what does it cover?
• Will you give me a written estimate before doing repairs?

Be cautious with anyone who insists you need a full system replacement after a quick look, without explaining why repair is not an option. A second opinion is reasonable for any major recommendation.

What affects the cost of HVAC service

Prices vary by region and company. In general, these factors matter most:

• The type and age of your system.
• Whether you are on a maintenance plan.
• Emergency, after-hours or peak-season calls.
• Parts availability, especially for older equipment.
• Access to the equipment (attic, crawl space, rooftop).

Book before the rush

Find HVAC and AC repair services in the directory, compare reviews, and schedule your seasonal check while appointments are still easy to get. You can also browse by city to see who serves your area.