The short answer
Check the filter monthly and replace it when dirty, keep the outdoor unit clear, keep vents and returns open, test carbon monoxide alarms, and book a professional tune-up once a year for each system – cooling in spring, heating in fall. Heat pumps work in both seasons, so many makers suggest two visits a year.
Every month
- Check the air filter; replace it when dirty. One-inch filters often last one to three months; thicker media filters longer.
- Make sure supply vents and return grilles are open and not blocked by furniture or rugs.
- Glance at the indoor unit for water or rust stains.
Spring (before cooling season)
- Clear leaves and debris from around the outdoor unit; keep about two feet clear.
- With power off at the disconnect, gently rinse the outdoor coil fins with a hose if they are dirty.
- Make sure the condensate drain runs freely; follow the maker’s guidance for flushing it.
- Test cooling on a mild day, before the first heat wave.
- Book the cooling tune-up.
Fall (before heating season)
- Replace the filter.
- Test smoke and carbon monoxide alarms; replace batteries or expired alarms.
- Check furnace vent pipes outside are clear, and plan to keep them clear of snow.
- Run the heat for a few minutes on a cool day; a brief dusty smell is normal.
- For a humidifier, replace the pad and turn the water on.
- Book the heating tune-up.
What a professional tune-up should include
Ask for a written checklist. A thorough visit usually covers:
- Cooling and heat pumps: clean or inspect coils, check refrigerant pressures and temperatures, test the capacitor and contactor, clear the drain, measure airflow and temperature split.
- Furnaces: inspect the burners, flame sensor, igniter and heat exchanger, test safety switches, check venting and gas pressure, and test for carbon monoxide.
- Both: tighten electrical connections, check the blower, test thermostat operation, and note anything wearing out.
A tune-up is not a sales visit. Get any recommended replacement in writing and take time to compare.
Step-by-step guides for each system
- How often to change your air filter
- AC maintenance – the spring routine
- Furnace maintenance – the fall routine
- Heat pump maintenance – both seasons
- Mini-split maintenance – ductless heads and filters
- Duct cleaning and duct sealing – what is worth paying for
- Thermostat settings and indoor humidity
- Carbon monoxide safety
Warranties and maintenance
Many manufacturers require product registration within a set time after installation, and some require proof of regular maintenance, to keep the full equipment warranty. Keep invoices from every service visit.
Are maintenance plans worth it?
Many companies sell yearly plans with two visits, priority scheduling and repair discounts. They can be worth it if you would book the visits anyway. Read what is included, whether it renews automatically, and how to cancel.
Find an HVAC company near you
Local heating and cooling companies by metro area, listed A to Z with phone numbers, services and emergency options.
Questions
How often should HVAC be serviced?
Once a year for a furnace or air conditioner, timed before its season. Heat pumps run all year, so many makers suggest service twice a year.
What MERV filter should I use?
Use the rating your system maker allows. Higher MERV filters catch more particles but can restrict airflow on systems not designed for them. Many homes use MERV 8 to 11.
Can I clean my own AC coil?
You can rinse the outdoor coil gently with a hose, with the power off. Indoor coils and anything involving refrigerant or electrical parts are best left to a technician.
Related guides
Updated October 2026 by the Heating and Cooling editorial team. General information for homeowners, not professional advice – rules and equipment differ. When gas, carbon monoxide, electricity or anyone’s safety is involved, call 911 or your utility. How we write our guides · HVAC glossary