Heat pump services: what to know

What the job involves, what changes the price, and what to ask a pro.

What heat pump services is

Heat pump services cover installing, servicing and repairing heat pumps, whether ducted or ductless. A heat pump heats and cools a home with one system by moving heat in and out of the house, so its service includes both heating and cooling parts.

Signs you need it

  • The system heats or cools less than it did, or the house is slow to reach the set temperature.
  • The outdoor unit ices over in cold weather and stays iced, or the defrost cycle runs far too often.
  • The auxiliary or emergency heat strips come on constantly, which drives up electric use.
  • The system switches to heat or cool at odd times, or the reversing valve makes a clicking or hissing sound.
  • Water leaks from the indoor unit, or the outdoor unit makes new knocking, grinding or buzzing sounds.
  • The system short cycles, or a breaker trips when the compressor starts.

What the pro does

  • Check the thermostat settings, the outdoor disconnect and the control board for fault codes.
  • Measure pressures, superheat and subcool in both heating and cooling modes, to find a low charge or a restriction.
  • Test the reversing valve, the defrost sensors and the defrost board, which decide when the outdoor coil clears ice.
  • Check the auxiliary heat strips and their contactors and the amp draw of the compressor and fan motors.
  • Clean the outdoor coil and the indoor coil, and clear the condensate drain.
  • Run the system through heating, cooling and defrost to confirm each mode works, and record the readings.

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Whether the work is service, installation or repair, since each has different parts and labor.
  • Ducted or ductless design, which changes the equipment and access.
  • Which part failed, such as a reversing valve, a defrost board or a compressor, each of which varies widely in labor.
  • Refrigerant needs, since a leak must be found and repaired before a recharge, and handling refrigerant commonly requires a certification.
  • Access to the outdoor unit and the indoor air handler, such as an attic, a crawl space or a tight closet.
  • Whether the system has a backup heat source that also needs servicing.
  • System age and whether parts are still available for the model.

What a written quote should spell out

  • The fault found in each mode, with the readings taken in heating and cooling.
  • The refrigerant amount and type added or recovered, and the leak repair if one was needed.
  • Each replacement part with its model number and warranty.
  • Auxiliary heat strip and contactor work, listed separately.
  • Coil cleaning and drain service, if included in the visit.

Questions to ask before you hire

  • Will you test the system in both heating and cooling modes before you tell me it is fixed?
  • Will you check the defrost board and the sensors, or only clear the ice?
  • If the reversing valve has failed, what are the repair options?
  • Is my refrigerant low because of a leak, and will you find and repair it?
  • Do you service the brand and model I have, and what parts do you carry?
  • How will you check that the backup heat strips are not running more than they should?
  • Will you give me the readings in writing, for heating and for cooling?

Red flags

  • The pro tests only in cooling and says the heating mode is fine without testing it.
  • The pro adds refrigerant without checking for a leak.
  • The pro replaces the reversing valve without testing the coil and the system pressures first.
  • The pro suggests replacing the whole system before running the defrost and heat strip tests.

What you can do yourself

You can check the thermostat settings and batteries, replace a dirty filter, and keep the outdoor unit clear of snow, leaves and debris. Do not clear ice with a tool or hot water. Refrigerant, the reversing valve, the defrost controls and the electrical parts belong to a licensed technician with refrigerant handling certification.

Licenses and permits

Heat pump work is commonly done by licensed HVAC contractors, and refrigerant handling commonly requires a certification. Check with your state or local licensing agency for the requirements that apply to your service or installation.

Heat pump services questions

Why does my heat pump run the backup heat?

It runs backup heat when the heat pump cannot keep up, such as in very cold weather, during defrost, or when the thermostat is set up a large amount at once. A technician checks whether the backup is running more than it should.

Why is the outdoor unit iced over in winter?

A heat pump defrosts its outdoor coil in cold weather, and some frost is normal. Heavy or constant ice suggests a defrost fault, a sensor problem, low refrigerant or a blocked airflow path, and should be checked.

Why does my heat pump make a whooshing or clicking sound?

Clicks at the start and stop of a cycle are common, and a soft whoosh when the unit switches into or out of defrost is normal. A repeating click or a steady hiss can point to a reversing valve or a refrigerant problem, so have it checked.

Do I need service every year?

Yes, once a year is the usual schedule. Service in both heating and cooling modes is the best way to catch faults before they leave you without heat or cooling.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

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