ManualHarbor

How Often Should You Service Your Air Conditioner?

Updated October 9, 2026

A central air conditioner should get a professional check-up at least once a year, ideally in spring before the cooling season starts. That's the schedule ENERGY STAR and Carrier recommend. If your system is a heat pump that also heats your home, Lennox, Carrier and Trane all suggest two visits a year, one before cooling season and one before heating season. Between visits, ENERGY STAR says to inspect the filter monthly. This Old House (using Fixr pricing) puts a typical tune-up at $65 to $200, and Trane says a seasonal maintenance visit can cost $100 to $350.

What official guidance and manufacturers recommend

Recommendations vary a little, but every source we reviewed calls for professional service at least once a year. The main difference is whether equipment that runs all year should get a second visit.

  • ENERGY STAR — Equipment: Central cooling and heating; Recommended professional service: Yearly check-up before the season starts: cooling system in spring, heating in fall
  • U.S. Department of Energy — Equipment: Heat pumps; Recommended professional service: At least once a year
  • Carrier — Equipment: Central air conditioners; Recommended professional service: At least once a year, ideally in spring
  • Carrier — Equipment: Heat pumps; Recommended professional service: At least annually; ideally twice (spring for cooling, fall for heating)
  • Trane — Equipment: AC, heat pump, furnace; Recommended professional service: Spring visit for AC or heat pump; fall visit for furnace or heat pump
  • Lennox — Equipment: Heat pump systems; Recommended professional service: Twice a year, before the cooling and heating seasons
  • This Old House — Equipment: Central AC; Recommended professional service: Once a year, usually spring; older systems may benefit from two

Sources: ENERGY STAR maintenance checklist; DOE Energy Saver (archived); Carrier AC tune-up and heat pump service pages; Trane maintenance tips; Lennox homeowner guide 507657-01; This Old House.

Spring timing is partly practical. ENERGY STAR notes that HVAC contractors get busy once summer arrives, and This Old House says booking in late winter or early spring can help you avoid higher peak-season prices. If you have a ducted or ductless heat pump (see our heat pump guides), the second visit matters more because the same compressor and coils work through the winter.

What a professional tune-up should include

A proper tune-up includes measurements and tests, not just a quick look. Based on the DOE technician checklist, the ENERGY STAR checklist and Carrier's 12-point list, a complete visit should cover:

  • Refrigerant: check the charge, test for leaks and recover any refrigerant removed from the system rather than releasing it (DOE).
  • Airflow: measure airflow across the indoor coil and clean and adjust blower parts. ENERGY STAR says airflow problems can cut efficiency by up to 15 percent.
  • Coils: inspect and clean the indoor evaporator coil and outdoor condenser coil as needed. Dirty coils make the system run longer (ENERGY STAR).
  • Electrical: tighten connections, measure motor voltage and current, and test the run capacitor (ENERGY STAR, Carrier).
  • Condensate drain: inspect and clear the drain so water can't back up (ENERGY STAR, Carrier).
  • Controls and thermostat: confirm the system starts and stops properly, that heating and cooling can't run at the same time, and that the thermostat reads accurately (DOE, ENERGY STAR).
  • Moving parts: lubricate motors and check any belts for wear (DOE).
  • Ducts and filter: check ducts for leaks and change the filter (DOE, Carrier).

Carrier notes that many contractors provide a written summary of the tests and results. Keep it, because it doubles as your maintenance record for warranty purposes (see below).

These checks have a purpose. A 2018 DOE review of field studies found that 70% to 90% of home air conditioners and heat pumps have at least one performance problem caused by installation or inadequate maintenance.

What a tune-up costs

  • This Old House, pricing from Fixr (updated 03/27/2026) — Scope: AC tune-up, all types; Price range: $65–$200; average $133
  • This Old House / Fixr — Scope: Central AC; Price range: $85–$200; average $143
  • This Old House / Fixr — Scope: Window AC; Price range: $65–$150; average $108
  • This Old House / Fixr — Scope: Mini-split system; Price range: $200–$400; average $300
  • Trane (manufacturer maintenance page) — Scope: Seasonal HVAC maintenance visit; Price range: $100–$350, depending on local cost of living and what the visit includes

Trane also advises caution with visits priced below $70, since a very cheap visit may not cover much. Carrier's tune-up page quotes $75 to $200, but it cites This Old House, so it is not an independent third estimate. This Old House notes that a standard tune-up doesn't include repairs. Fixes found during the visit, such as refrigerant work, are billed separately.

Example: does a tune-up pay for itself in energy savings alone?

DOE's 2018 research review puts the extra energy savings from tuning up an existing AC or heat pump at about 5%. Here is how that compares with the cost of a visit.

  • Formula: break-even cooling use (kWh per year) = visit cost ÷ (savings fraction × electricity price)
  • Assumptions: $133 visit (This Old House average), 5% savings (DOE), 18.19¢/kWh (EIA U.S. residential average, January–July 2026)
  • Result: $133 ÷ (0.05 × $0.1819/kWh) ≈ 14,600 kWh of cooling electricity per year

If your system uses less cooling electricity than that, the energy savings alone won't cover the visit. The stronger reasons for yearly service are finding faults early, keeping your warranty valid and avoiding a breakdown in peak season. Use your own utility rate and usage, since prices vary widely by state.

What you can safely do between visits

Before touching any part of the system, turn it off at the thermostat. Then cut power at the breaker or the service disconnect. Lennox's homeowner guide and Carrier both make this the first step. Your owner's manual takes priority over any general list.

  • Check the filter monthly. ENERGY STAR recommends a monthly look. If you're unsure of your schedule, DOE suggests cleaning or replacing it every month or two during cooling season, and more often with pets, dust or constant use.
  • Keep the outdoor unit clear. Trane recommends at least two feet of open space on every side and four feet above the unit. Trim plants back and aim grass clippings away from the cabinet.
  • Rinse, don't blast. If the condenser coil looks dirty, Trane says a gentle spray from a garden hose is fine, but never use a pressure washer. Carrier specifies doing this with the unit off.
  • Keep vents open. Furniture, rugs and drapes over supply or return vents restrict airflow (Trane).
  • Watch the drain. Lennox suggests asking your dealer to show you how to check the condensate drain line, then checking it monthly. Puddles near the indoor unit can mean a clogged drain or a frozen coil (Trane).
  • Leave bent fins to a pro. DOE says a qualified contractor can straighten coil fins with a fin comb.
  • Window units. For room air conditioners, DOE recommends checking the window seal at the start of each cooling season and covering or removing the unit for winter. LG recommends cleaning a window unit's filter every two weeks.

A smart thermostat can remind you about these tasks. Google says Nest filter reminders track how long your system runs instead of using a fixed calendar, but they're off by default. ecobee lets you set HVAC maintenance reminders that arrive by email.

Refrigerant and electrical work aren't homeowner tasks. Under EPA Section 608 rules, anyone servicing equipment that could release refrigerant must be certified, and intentionally venting refrigerant is prohibited. Carrier warns that capacitors can hold a lethal charge even when the power is off.

Warranty maintenance requirements

Some manufacturers make maintenance a condition of warranty coverage. For example, Trane's Base Limited Warranty for outdoor AC and heat pump units made on or after March 1, 2024 says the equipment must be installed, operated and maintained by a licensed HVAC service provider according to Trane's instructions. Not following those instructions voids the warranty. The same document says Trane may ask for written proof of preventive maintenance. It covers replacement parts but not labor, and it excludes air filters and refrigerant. Registering online within 60 days extends the coverage term.

We verified Trane's language only. Other brands use different terms, so read the warranty certificate for your own model. Keep dated invoices or technician reports for every visit.

Signs you need service before the next scheduled visit

  • The system no longer cools your home adequately (DOE).
  • Energy bills rise even though your usage hasn't changed, or some rooms are much warmer than others (Trane).
  • Water collects around the indoor unit (Trane).
  • Ice forms on the indoor coil in summer, which Carrier links to low refrigerant or a clogged filter.
  • New grinding, rattling or hissing sounds, or unusual smells at startup (Trane, Carrier).
  • A burning electrical smell. Trane says to turn the unit off right away and call a technician.
  • The outdoor unit has been in floodwater. Trane says not to try fixing water-damaged electrical parts yourself.
  • The breaker keeps tripping. DOE suggests checking fuses and breakers and letting the unit sit for five minutes before resetting. If the problem comes back, call a technician.

FAQ

Is once a year enough for a central air conditioner?

For a cooling-only system, yes. That's what ENERGY STAR and Carrier recommend, scheduled in spring. This Old House notes that older systems may benefit from a second visit. If your outdoor unit is a heat pump, the manufacturers we reviewed recommend two visits.

Can I tune up my own air conditioner?

You can handle filters, clearing debris, gentle coil rinsing with the power off, and checking the drain. Measuring and adjusting refrigerant charge, testing capacitors and working on electrical parts require a licensed technician. Refrigerant handling also requires EPA certification.

When is the best time to book AC maintenance?

Spring, before you need cooling. Trane suggests late February to early May, depending on where you live. ENERGY STAR recommends tying spring and fall check-ups to the clock changes so they're easy to remember.

Will skipping maintenance void my warranty?

It can, depending on the brand. Trane's current warranty requires maintenance by a licensed provider and allows the company to ask for proof. Check your own certificate and keep records of every visit.

Do window air conditioners need professional service?

Most of a window unit's routine care is cleaning the filter, checking the window seal and storing the unit for winter. This Old House does list professional tune-ups for window units ($65–$150, average $108, using Fixr data). Check your manual for anything beyond routine cleaning.

Related guides

Sources