What You Need to Do to Maintain a Heat Pump

A heat pump needs four kinds of regular care to keep working efficiently: cleaning or replacing the air filter, clearing debris from the outdoor unit, having the refrigerant checked by a technician, and scheduling a professional inspection once a year. Most of these tasks are straightforward enough for a homeowner to handle. The refrigerant work and the annual inspection must be done by a licensed HVAC technician, because the system is sealed and pressurized.

The good news is that heat pumps have fewer moving parts than furnaces or air conditioners, so they tend to need less maintenance overall. The bad news is that they work year-round—heating in winter and cooling in summer—so neglecting them costs you money every month in wasted energy.

Key Takeaways

  • Replace or clean your air filter every one to three months, depending on whether you have pets or allergies and how much dust your home collects.
  • Clear leaves, grass clippings, and snow from around the outdoor unit at least twice a year, and more often if you live near trees.
  • Have a licensed HVAC technician inspect your heat pump once a year, usually in the fall before heating season starts.
  • The refrigerant level should be checked during the annual inspection; low refrigerant means a leak that only a technician can find and repair.
  • Keeping the indoor and outdoor units clean and unobstructed is the single most important thing you can do to extend the life of your system.

Changing and Cleaning the Air Filter

The air filter is the easiest maintenance task and the one that makes the biggest difference to how hard your heat pump has to work. A clogged filter forces the system to run longer to heat or cool your home, which wastes energy and wears out the compressor faster.

Most heat pumps use a standard 1-inch or 4-inch pleated filter that slides into a slot in the indoor unit, usually in a basement, attic, or utility closet. Check the filter every month by looking at it against a light—if you can't see light through it, it's time to replace it. In a home with no pets and low dust, you might change it every three months. If you have pets, allergies, or live in a dusty area, change it every month.

The filter size is printed on the frame (for example, 16x25x1 or 20x20x4). Buy the same size at any hardware store or online. Turn off the heat pump before you remove the old filter, slide the new one in with the arrow pointing in the direction of airflow, and turn the system back on. Keep a few spare filters on hand so you're not caught without one.

Clearing Debris from the Outdoor Unit

The outdoor unit—the metal box that sits outside your home—needs clear space around it to pull in air and release heat. Leaves, grass clippings, snow, and ice block that airflow and force the compressor to work harder.

Check the outdoor unit at least twice a year: once in late fall after leaves have dropped, and once in early spring. Remove any leaves, twigs, or grass clippings by hand or with a soft brush. If snow piles up against it during winter, gently brush it away (do not use a pressure washer or sharp tools, which can damage the aluminum fins). In summer, make sure grass and weeds are not growing up around the base.

Keep at least two feet of clear space on all sides of the outdoor unit if possible. If your unit is in a tight space, trim back bushes and trees so air can flow freely. Do not cover the unit with a tarp or box during winter—modern heat pumps are designed to operate in cold weather, and covering them traps moisture and can cause rust.

Scheduling an Annual Professional Inspection

Once a year, usually in the fall before you start using the heat pump for heating, have a licensed HVAC technician come out for a maintenance visit. This inspection typically costs between $100 and $200, depending on your region and the technician's rates.

During the visit, the technician will check the refrigerant pressure, test the thermostat, inspect electrical connections, lubricate moving parts if needed, and clean the indoor coil. They will also look for signs of wear or damage that could turn into bigger problems later. If they find low refrigerant, they will locate the leak and repair it before refilling the system—you should never just add refrigerant without fixing the leak.

Some HVAC companies offer maintenance plans where you pay a flat fee (usually $150 to $300 per year) and they come out twice a year, in spring and fall. These plans often include priority service if something breaks and may give you a small discount on repairs. Whether you choose a plan or call for a single annual visit, the key is to do it every year, not to skip years and then try to catch up.

Checking and Maintaining the Refrigerant

Refrigerant is the fluid that circulates through your heat pump to move heat in and out of your home. A properly sealed system should never lose refrigerant—if the level is low, there is a leak somewhere.

You cannot check the refrigerant yourself without special gauges and training, so this is always a technician's job. During the annual inspection, they will connect gauges to the service ports on the outdoor unit and check the pressure. If it is low, they will use a leak detector to find where the refrigerant is escaping, repair the leak, and then refill the system to the correct level.

Never ignore low refrigerant. A system running low on refrigerant will not heat or cool properly, will use much more electricity, and can damage the compressor. If your heat pump is not keeping up with the temperature you set, or if you see ice forming on the outdoor unit in winter, call a technician right away—these are signs of low refrigerant or another serious problem.

Keeping the Indoor Coil Clean

The indoor coil is inside the unit in your home and is harder to access than the outdoor unit, but it also collects dust and debris over time. A dirty indoor coil reduces efficiency and can lead to mold growth if moisture sits on it.

The technician will clean the indoor coil during the annual inspection. Between visits, you can help by making sure the area around the indoor unit is clean and dry, and by changing the air filter regularly—a clean filter keeps dust from settling on the coil in the first place.

If you notice water pooling around the indoor unit, or if the unit smells musty, call a technician. These are signs that the coil is dirty or the condensate drain is clogged, and both need professional attention.

What to Do if Your Heat Pump Stops Working

If your heat pump suddenly stops heating or cooling, do not assume it needs a major repair. Start by checking the thermostat—make sure it is set to the right mode (heat or cool) and that the temperature setting is above or below the current room temperature. Then check the air filter and the outdoor unit for obvious blockages.

If the system still does not work, turn it off and call a licensed HVAC technician. Do not try to add refrigerant yourself or take apart any part of the system. Heat pumps are complex, and mistakes can be expensive and dangerous.

If your heat pump is more than 15 years old and needs a major repair, ask the technician whether repair or replacement makes more sense. Newer heat pumps are much more efficient and may save you money on energy bills even if the upfront cost is high.

Frequently Asked Questions

How often should I have my heat pump serviced?

At least once a year, ideally in the fall before heating season. Some technicians recommend twice-yearly service—spring and fall—especially if you use the system heavily or live in a dusty or humid climate. Check your warranty to see if annual service is required to keep it valid.

Can I clean the outdoor unit myself?

Yes, you can remove leaves and debris by hand or with a soft brush. Do not use a pressure washer, which can bend the fins and damage the unit. If the fins are bent, a technician can straighten them with a special tool, but it is better to avoid the damage in the first place.

What does it mean if my heat pump is making a hissing sound?

A hissing sound usually means refrigerant is leaking from the system. Turn off the heat pump and call a technician right away. Running the system with a leak will damage the compressor and make the repair much more expensive.

Do I need to cover my outdoor heat pump unit in winter?

No. Modern heat pumps are designed to work in freezing temperatures and need to pull in outside air to operate. Covering the unit traps moisture, causes rust, and blocks airflow. Just brush away heavy snow or ice if it piles up against the unit.

How much does it cost to repair a heat pump?

Repair costs vary widely depending on what is broken. A straightforward fix like replacing a capacitor might cost $150 to $300. A refrigerant leak repair could be $300 to $1,000 or more. A compressor replacement, the most expensive repair, can cost $1,500 to $3,000 or higher. Regular maintenance helps catch small problems before they become big ones.