HVAC · Lesson 12 of 13Beginner6 min read

Maintenance and Doing Your Own Work

Owners can do a lot to keep a system healthy, and none of it requires opening the equipment. This lesson lists those jobs, explains what a professional tune-up covers, and draws a clear line around the work that the law or plain safety reserves for licensed and certified pros.

Your maintenance list

  • Filters. Check monthly and change at least every three months, or as your system’s manufacturer recommends; more often with pets, dust or constant use (Change a Furnace Air Filter).
  • The outdoor unit. Keep leaves, grass clippings, snow and plants away from it, following the clearances in its manual. Don’t stack things on top: the fan blows up through it.
  • Vents outside. Keep the furnace’s vent and air-intake pipes, the dryer vent and other outlets clear of snow and debris, as the U.S. Fire Administration advises.
  • Registers and returns. Keep them open and unblocked, and vacuum the grilles.
  • The thermostat. Replace batteries if it uses them; review the schedule each season.
  • The condensate drain. Know where it ends and check that it drips in cooling season. EPA advises keeping drip pans clean and drain lines flowing; follow your manual for any drain care it recommends.
  • Alarms. Test CO and smoke alarms monthly (Test Smoke and CO Alarms).
  • Clearance. Keep anything that can burn at least 3 feet from heat sources (USFA), and keep the furnace area free of stored items.

The yearly professional checkup

ENERGY STAR suggests checking the cooling system in the spring and the heating system in the fall. Its checklist for a contractor’s visit includes:

  • Every system: checking thermostat settings, tightening electrical connections and measuring motor voltage and current, lubricating moving parts, inspecting the condensate drain, and checking that the controls start, run and shut down safely.
  • Cooling: cleaning the indoor and outdoor coils, checking and adjusting the refrigerant level, and cleaning and adjusting the blower to keep the airflow right.
  • Heating: checking gas (or oil) connections, gas pressure, burner combustion and the heat exchanger.

CPSC, CDC and the U.S. Fire Administration all advise a yearly professional inspection of fuel-burning heating equipment, including the chimney, flue and vents.

furnaceburners, gas valve,controls, wiring:pros onlyfilter slotvents: keep cleardrain line endthermostatoutdoor unitrefrigerant, 240 V,panels: pros onlykeep the area clearyours to care forlicensed or certified pros only
The line between owner care and professional work. Sources: U.S. EPA Section 608; ENERGY STAR maintenance checklist; U.S. Fire Administration.

What needs a pro, and why

  • Refrigerant. Federal law: EPA Section 608 requires certification to attach gauges, add or remove refrigerant, or open the refrigerant circuit, and venting refrigerant is illegal. Refrigerant under pressure can also cause serious cold burns.
  • Gas. Gas piping, gas valves, burners, ignition and venting are where fires and carbon monoxide come from. Leave them to qualified technicians and your gas utility.
  • Electrical inside the equipment. Furnaces and air handlers run on 120 volts or more; outdoor units and electric heat on 240 volts. Their control boards, contactors and motors are a technician’s job.
  • Installing or replacing equipment. Sizing, ducts, refrigerant lines, gas, venting and wiring all come together. Many places require a permit and an inspection, and some states and localities require contractors to be licensed. ENERGY STAR suggests checking your state’s license and insurance requirements before you hire.

  1. First jobs

    Checks and simple care. No panels off, no tools beyond a flashlight.

  2. Next steps

    The manual in hand, the power off, and a helper the first time.

    • Replace a low-voltage (24-volt) thermostat, following its instructions
    • Check that the condensate drain flows, as the manual describes
    • Measure humidity and run a dehumidifier
    • Clean bath-fan grilles and register covers
    • Bleed air from hot-water radiators, if your boiler manual allows
    • Install a window air conditioner, following its instructions

  3. Intermediate jobs

    Research, the right protective gear, and a mentor. Mistakes can damage equipment or the house.

    • Seal accessible duct joints with mastic or metal tape
    • Insulate ducts in an attic or crawlspace
    • Air-seal and add attic insulation
    • Hose the dust off an outdoor coil, power off, as the manual describes
    • Straighten bent coil fins with a fin comb

  4. Leave these to licensed or certified pros

    The law, your safety or your warranty reserves them.

    • Anything that touches refrigerant: gauges, charging, leak repair, recovery (EPA Section 608)
    • Gas piping, gas valves, burners, ignition and venting
    • Electrical work inside furnaces, air handlers and outdoor units
    • Combustion, CO and heat-exchanger testing
    • Installing or replacing furnaces, boilers, air conditioners and heat pumps (permits may apply)
    • Line-voltage thermostats and new circuits
    • Duct design, leakage testing and balancing
    • Geothermal loops and wells

Hiring a contractor

ENERGY STAR’s tips for hiring: check your state’s license and insurance requirements, ask for references and call them, expect the contractor to size the system from your home’s size, insulation and windows, ask them to inspect the ducts for leaks and insulation and to measure the airflow, and sign a written proposal with prices, model numbers, the schedule and the warranty before work starts. For refrigerant work, EPA suggests asking to see the technician’s Section 608 certification.

You canGood habits

  • Keep the manuals for your furnace, air handler, outdoor unit and thermostat together, with a log of filter changes and service visits.
  • Turn off power at the equipment’s switch or breaker before you do anything near moving parts, such as cleaning around the outdoor unit.
  • Work with a helper the first time you try anything new.

StopWhen to stop

  • If doing a job would mean removing a panel the manual reserves for a technician, stop there.
  • Never bypass a safety switch, run a furnace with its doors off, or add refrigerant from a store-bought can to a home system.
  • Any CO alarm, gas smell, burning smell or water near electrical parts: follow the emergency steps in Lesson 11.

Check yourself

Tap an answer to check it, or open “Show the answer.”

  1. How often does ENERGY STAR say to check your HVAC filter?

    Show the answer

    Every month, changing it at least every three months. Check monthly, change at least every three months, more often if it looks dirty.

  2. Which job requires EPA Section 608 certification?

    Show the answer

    Attaching gauges and adding refrigerant. Any work that opens the refrigerant circuit, including attaching gauges, requires certification.

  3. When does ENERGY STAR suggest scheduling checkups?

    Show the answer

    Cooling in the spring, heating in the fall. Pre-season: cooling in spring, heating in fall.

  4. Before hiring an HVAC contractor, ENERGY STAR suggests you:

    Show the answer

    Check your state’s license and insurance requirements and call references. Licensing, insurance, references, a proper sizing calculation and a written proposal.

Go deeper

Sources

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A free course from Teddy Rook Book. It explains how HVAC systems work in general and follows U.S. sources; your equipment’s manuals and the local code are the final word, along with your gas utility for anything involving gas.

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