How often should a furnace and air conditioner be serviced?

Updated November 10, 2026 · KeystoneProGuide editorial team

How often does an HVAC system need professional service?

Once a year for each system. ENERGY STAR recommends annual pre-season check-ups by a contractor, the cooling system in spring and the heating system in fall. A heat pump does both jobs, so it is one system needing attention before each season. Its reasoning for the timing is practical: contractors get busy once summer and winter arrive, and it suggests tying the visits to the clock changes in spring and fall so you remember them.

Why does the heating visit matter so much?

Because fuel-burning heat produces carbon monoxide when something goes wrong. Three federal agencies give the same interval:

• The U.S. Consumer Product Safety Commission urges a yearly professional inspection of all fuel-burning heating systems, including furnaces, boilers, water heaters, chimneys, flues and vents.
• The U.S. Environmental Protection Agency advises having a trained professional inspect, clean and tune up the central heating system, including furnaces, flues and chimneys, every year, and repairing any leaks promptly.
• The Centers for Disease Control and Prevention says to have the heating system, the water heater and any other gas, oil or coal burning appliance serviced every year by a qualified technician.

If you heat with gas or oil, the fall visit is the one not to skip.

What should happen at each visit?

ENERGY STAR's maintenance checklist splits the work by season.

• Spring, cooling. Clean the evaporator and condenser coils, check the refrigerant level, and clean and adjust the blower. ENERGY STAR says too much or too little refrigerant lowers efficiency and shortens the equipment's life, and that airflow problems can cut efficiency by up to 15 percent.
• Fall, heating. Check gas or oil connections, gas pressure, burner combustion and the heat exchanger. A dirty burner or a cracked heat exchanger makes the burner operate improperly.
• Both. Check the thermostat, tighten electrical connections, lubricate moving parts, check the condensate drain and confirm the system starts, runs and shuts off properly.

A walk-through of a visit in time order is in what to expect from an HVAC visit.

How often should filters and alarms be checked?

• Filters: every month, and changed when dirty, at least every 3 months, according to ENERGY STAR. Winter and summer, when the system runs most, are when monthly checks matter most.
• Carbon monoxide alarm batteries: the CDC suggests checking them when you change the clocks each spring and fall, the same reminder ENERGY STAR suggests for booking service.
• Carbon monoxide alarms themselves: replace them as the manufacturer directs or every 5 years, says the CDC.

Does a heat pump or boiler change the schedule?

Not the yearly rhythm, but the details shift. A heat pump heats and cools with the same equipment, so it gets the spring cooling checks and the fall checks of controls and electrical parts. ENERGY STAR says heat pump filters should be cleaned when they look dirty or when the unit's filter light comes on, and its checklist includes the condensate drain of a heat pump running in cooling mode. A boiler burns fuel, and the CPSC's yearly inspection list names boilers alongside furnaces. A house with a boiler and a separate central air conditioner therefore needs two visits a year, one for each.

What does yearly service cost?

The cost surveys give national ranges. HomeAdvisor puts a furnace inspection at $80 to $100 and a full tune-up at $125 to $200. Angi puts yearly HVAC maintenance fees at $60 to $550.

If you are offered the visits as an annual plan, the Federal Trade Commission's advice on service contracts applies: work out the yearly cost, check what is excluded and whether there are fees per visit, and remember that a contract is not a good value if it covers nothing your equipment warranty does not. For some households, the FTC says, putting money aside is the better option.

When is a Pennsylvania winter a bad time to wait?

Any time the heat is marginal in fall. Contractors are busiest once the cold arrives, which is ENERGY STAR's reason for booking the heating check-up beforehand. If a household cannot afford a repair that comes due in winter, Pennsylvania's LIHEAP season runs November 2, 2026 through April 23, 2027, and its crisis grants cover broken heating equipment that must be fixed or replaced for eligible households.

How long until replacement?

ENERGY STAR does not give a lifespan, but it does give the ages at which it suggests considering replacement: more than 10 years for a heat pump or air conditioner and more than 15 years for a furnace or boiler, especially if repairs are frequent and bills are rising. Reaching those ages is a reason to have the system evaluated, and a good time to get a load calculation done before anything fails in a cold snap. ENERGY STAR also notes that a heat pump can often go in when a central air conditioner or furnace needs replacing, as a drop-in replacement using the same ducts.

Contractors who offer seasonal service are listed on the HVAC contractors directory page, and the price ranges for replacement are in the cost guide.

Sources

1. Maintenance Checklist, ENERGY STAR
2. Heat & Cool Efficiently, ENERGY STAR
3. Home Heating Equipment, U.S. Consumer Product Safety Commission
4. Carbon Monoxide's Impact on Indoor Air Quality, U.S. Environmental Protection Agency
5. Carbon Monoxide (CO) Poisoning Basics, Centers for Disease Control and Prevention
6. When is it time to replace?, ENERGY STAR
7. Air-Source Heat Pumps, ENERGY STAR
8. How Much Does It Cost to Repair a Furnace?, HomeAdvisor
9. How Much Does a New Furnace Cost? [2026 Data], Angi
10. Extended Warranties and Service Contracts, Federal Trade Commission
11. Apply for the Low Income Home Energy Assistance Program (LIHEAP), Pennsylvania Department of Human Services