Heating & Cooling

16 Reasons Your Heat Pump Doesn’t Blow Hot Air

Heat Pump Doesn't Blow Hot Air

Heat pumps are popular due to their energy efficiency. Heat pumps work by providing cool air in the summer and warm air in the winter. People often feel their heat pump isn’t working, especially those used to gas heat. Sometimes, this is the case due to a mechanical failure, but it can also be a misdiagnosis.

So, what are the reasons that your heat pump doesn’t blow hot air? These are the most common causes of a heat pump that won’t heat anymore:

  • Dirty filters, coils, and surfaces.
  • Leaks in the ductwork.
  • Malfunctioning thermostat or thermostat settings.
  • Frozen components.
  • Broken compressors, coils, and other parts.
  • There is no power or not enough in general.
  • It’s running a defroster.
  • It’s cold outside (I’m not being silly. I’ll explain, I promise)
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Heat Pump Not Blowing Hot Air

Heat pumps are notorious for having problems when you need them to work during a cold season. There are countless reasons it might stop working as it should, so let’s review each below in detail. Let’s explore why my heat pump is not heating.

1. The Exterior Condenser is Dirty

After years of use, all exterior condenser coils will eventually accumulate dust and debris, restricting airflow. When air is pulled through the vents, it also collects dirt, dust, grass clippings, and other debris you don’t want. You can fix this common problem by cleaning and servicing your system annually.

2. There’s a Blockage Outside

If you have plants around the edges of your heat pump’s vent outside, you’ll undoubtedly experience troubles. There should be a minimum of 2 feet of clearance around the unit to allow an optimal flow to pull air from outside to warm up the coils and get everything moving smoothly. Trim back any bushes, trees, or other plants blocking the vents.

Be sure fencing and other shelters around the heat pump meet clearance requirements.

3. The Filter Might Be Clogged

If you have a clogged air filter, you can do nothing except replace it (or clean it if you have a washable air filter). If your air filter is clogged, it restricts the airflow your heat pump needs to function correctly. You have slowed down dramatically.

Running a heat pump without the air filter is not recommended. However, it may be necessary for a night until you can get to the store to purchase a new one. If you run the unit without the air filter for long periods, the evaporator coil can get dirty and stop working.

4. There’s a Low Refrigerant Charge

If you have a low refrigerant charge, you won’t be able to transfer heat from the heat pump. The refrigerant is needed to cool the condenser coil to a point below the outside air to allow heat transfer. It should pull outside air across the condenser coil, transferring heat from the air to the refrigerant as it travels back to the evaporator coil. You’ll be left with little to no heat with a low charge.

If you have a low refrigerant charge, there is likely a leak somewhere in the system. You’ll have to seek professional help to deal with this common issue since it involves dismantling and repairing the internal components.

Check out the video below for details on how heat pumps transfer heat using refrigerant.

When the air ducts that transfer air from one place to another have holes or loose connections, there’s a huge issue. Air that leaks out obviously won’t make it to the places in your home that need warm air. Instead, it’ll leak outside, which doesn’t do anything for you and your family.

5. You Might Have No Power to the Condenser

Although it seems silly, there’s a chance that the circuit break leading to your condensing unit in the heat pump could be tripped. Check your electrical panel and service disconnects to be sure the breakers have not tripped.

If the breakers have not tripped, there could still be a break in the power somewhere. If your condenser is not starting, you could have a blown capacitor.

You should always call a licensed heating and cooling contractor to trace the problem when dealing with electrical components.

6. It’s an Old Unit

Unfortunately, old heat pumps tend to have one problem after another. As mechanical components age, they break down more frequently. If your heat pump is old, you’ll probably have to replace it soon.

New federal standards for R-410a refrigerants are making it harder and harder to repair older systems with R-22 refrigerants. Many HVAC contractors will no longer work on R-22 systems and only install replacement ones.

7. You Could Have a Broken Thermostat

Thermostats are often the reason that heat pumps stop working. If there’s no power, a tripped fuse, fried internals, dead batteries, or even small malfunctioning parts, your thermostat could prevent the pump from heating your home.

The good news is that most thermostats aren’t too expensive. Try out this Heagstat Thermostat to program your heat pump for cheap.

8. Thermostat Might Be on the Wrong Settings

On the other hand, you could’ve accidentally set the thermostat to the wrong settings. Most thermostats have cooling, heating, and auto options, which toggle back and forth between heat and cool to maintain the set temperature.

There is also a Fan setting for Auto and On. If your thermostat fan is ON, your heat pump may not be engaged. The fan will run continuously in the ON setting regardless of the outside temperature.

9. The Coils Are Iced Over

Frozen coils are caused by the heat pump not being used when cold outside. They could freeze if you wait too long, preventing them from warming up when you start the thermostat. To keep this from happening, turn on your heat pump before it reaches below 32 F (0 C).

If your heat pump coils are icing over, this is usually caused by restricted airflow around the unit or the defrost function not working correctly.

10. The Reversing Valve May Have Failed

Reversing valves in a heat pump system direct the flow of cold and warm air. This process depends on the valves to do their job correctly. If the valves in your system are broken, you could be flooding your home with cold air as the system gets “stuck” in one direction. They might be stuck sideways, blocking airflow completely.

11. Air Duct Leaks Are Possible

This can cause air to leak into the attic, basement, or crawl space, depending on where your ducts are located. Air loss like this can cause no heat to reach certain rooms in your home.

You’ll need the help of a professional technician to fix this issue.

12. The Compressor Might Have Failed

The compressor removes the cold air from your house while introducing warm air to reverse the natural cooling process of an air conditioner unit. If the compressor is malfunctioning, it won’t be able to heat your home. Instead, it’ll push out lukewarm air from all the vents.

Compressor repairs can be expensive. Usually, this occurs when the compressor is running dry with no refrigerant.

13. It’s Just Defrosting

Most heat pumps go through a defrosting period once an hour or so. This process prevents the coils from freezing, rendering your heat pump useless. During this time, the heat pump will focus on heating the coils rather than your home. It’s not broken; it’s just maintaining itself.

14. Your Thermostat is in Auto Recovery Mode

Programmable thermostats will undergo an Auto Recovery Mode period between scheduled temperature change settings. For example, my thermostat displays a RECO message between program settings.

During this time, your heat pump tries to change the temperature gradually, which could make the air feel cool. This is part of the energy-saving feature built into the thermostat.

15. Heat Pump Emergency Heat Not Working

Heat pumps have emergency heat strips that kick in to assist the heat pump when the temperature drops below 30 degrees. If your heat strips have failed, the system may be trying to engage the emergency heat, but it’s simply not responding.

If a heat pump’s emergency heat is not working, it could be due to a faulty thermostat, a tripped circuit breaker, or a malfunctioning heat strip. It is recommended to check these components and consult a professional HVAC technician to ensure proper functioning and avoid further damage.

16. It’s Cold Outside

Now, I know this seems like a dumb statement. Of course, it’s cold outside, and you’re running the heat for a reason. Let me explain what I mean.

Heat pumps work by transferring heat from outside air. In the video above, it outlines how the heat pump does this. However, if it’s 60 degrees outside, it stands to reason that there is more heat to transfer than when it’s 20 degrees outside.

Heat pumps typically operate on about a 20-degree differential. Your body temperature is 98.6 degrees. However, if the air coming out of your vents is at 85 degrees, it will feel as though your heat pump is not working correctly when it is.

The video below does an excellent job of explaining this phenomenon.

Should You Repair or Replace Your Heat Pump?

Replacing a heat pump can cost between $6,000 and $12,000. That’s a lot of money for anyone, regardless of income level. Sadly, all heat pumps are limited to only last for so long.

Let’s examine the pros and cons of replacing vs. repairing a heat pump:

Pros of Repairing a Heat Pump

  • You’ll save tons of money this way. Perhaps the biggest draw of replacing an existing heat pump system is that you don’t have to fork out those above $5.1K. Instead, you’ll only have to spend about $400 to $1,100.
  • Your home will have the same heat pump without you having to worry about introducing something foreign. You don’t have to replace random bits and pieces to ensure they function correctly.

Cons of Repairing a Heat Pump

  • You’ll inevitably have to repair even more parts. When heat pumps get old, you’ll have to replace one component after another. Keep reading for more information about how many years you can get out of your heat pump.
  • You’ll void the warranty in most cases. Many heat pumps with a warranty require professionals to be the only ones working on the unit. If you try to DIY the repair, you could risk getting rid of warranties for the rest of the duration.

Pros of Replacing a Heat Pump

  • Getting a brand-new heat pump means you don’t have to worry about problems for many years. You’ll also be able to relax without worrying about doing any of the research or work yourself.
  • As mentioned above, most heat pumps include a warranty. By hiring a professional to install, you’ll reap the benefits of a multi-year contract that covers all sorts of manufacturer defects.

Cons of Replacing a Heat Pump

  • Replacing a heat pump is very costly. It’s one of the most expensive repairs of your home’s air circulation system, but it’s essential during the year’s cold months.
  • If you experience any issues with a new heat pump, it could be because it’s completely new to your home’s circulation system. You might have to replace ducts, vents, and other parts to get it working properly.

How to Fix a Broken Heat Pump

Since there are so many causes of a malfunctioning heat pump, there’s no one way to explain how to fix every issue at once. However, you can follow specific safety guidelines to avoid getting hurt. If you’re worried about doing it yourself, always hire a professional.

Here’s the five-step process to diagnose and fix a broken heat pump:

  1. Find the source by testing the breakers with a multimeter. These tools allow you to determine what has electricity and what doesn’t. If everything is powered, you can start by cleaning the filter and vents and removing anything that might obstruct the exterior. You may have to hire a pro to diagnose the source.
  2. Turn off the power at the circuit breaker before you work on anything. It’s not worth risking your health to fix a heat pump. Once it’s all off, you can start to examine the unit.
  3. Once you’ve discovered the problem, see if you can do anything to repair it rather than having to replace it. Every part of a heat pump system costs less than a new pump, so why not save some money? In most cases, all you’ll need is a few hand tools.
  4. Consider hiring someone to fix the issue vs. doing it yourself. Some techs offer warranties on parts, while others don’t. If it’s something as simple as a filter replacement, you can remove the screws and replace the filter or clean it in seconds. Complex procedures that require pro help include air duct leaks, refrigerant issues, and valve problems.
  5. If the coils are frozen, you may be able to save them by warming them up. Typically speaking, the coils are warmed by running the heat pump. You might just have to give it a few hours to kick the frost off. If they’re permanently damaged, then they’ll require replacement.

Always test your work and ensure everything is secure before running your heat pump for several hours. If you forget to replace the filter or accidentally leave wires exposed, many problems can occur.

How to Get the Most Out of Your Heat Pump

Heat pumps are debatably some of the best inventions for cold environments. We all know how useful they can be, but there are several ways to extend the life of your heat pump while also getting more usage out of it.

Whether you live on a freezing mountain or a seaside city, you can benefit from this section. Here’s a list of methods that you can try out to get the most out of your heat pump:

  • According to Heat and Cool, you should clean your heat pump filter once every 8 to 12 weeks. If you use it every day during the winter, you might want to consider narrowing it down to 5 to 6 weeks. On the other hand, never let the time between cleanings exceed 15 weeks.
  • Follow the recommended maintenance schedule. Like an automobile, you can prevent small problems from becoming more severe if you follow the recommendations. These tips might include replacing the coils occasionally, checking electrical connections once a season, or getting new valves to keep the air flowing correctly.
  • Have your air conditioner and heat pump units inspected annually. These procedures should be done right before it gets cold outside. Inspections are inexpensive, provide peace of mind, and prevent you from freezing if something needs to be repaired.
  • Remove anything near vents around your home, and don’t forget to clean the dust off regularly. Lamps, fake plants, and entertainment centers can reduce the air circulation in your home. These setups can drastically reduce the warmth you get from your heat pump.
  • Consider getting a fan to blow warm air around the house. Contrary to popular belief, fans don’t create cold air. They simply move it faster, pulling stagnant air and making it feel better. Turning on a fan lets you quickly move the warm air from your heat pump to warm up your house.

How Long Do Heat Pumps Last?

Some heat pumps last longer than others. It should come as no surprise that people who live in a cold climate will use their heat pump more often than those in a warm area.

For example, you wouldn’t use a heat pump too often in Phoenix, Arizona, but just a hundred or so miles away in Flagstaff, you might freeze if you don’t! The people living in Flagstaff will get a shorter lifespan from their heat pumps since they’re using them much more often.

Glasco Heating & Air states that average heat pumps last about 15 years. With proper maintenance, you can increase that estimate by quite a bit. It’s not rare to see a house that gets between 20 to 25 years of top-notch usage from its heat pump.

On the other hand, if you always let the coils freeze and refuse to clean the filter, you’ll end up shaving years off of your heat pump. You’ll have to spend tons of money repairing and replacing them far more often than you should.

In short, heat pumps are designed to last for 15 years, but your maintenance routines (or lack thereof) can and will directly impact the unit’s longevity. Small cleaning and following the recommendations above will be the best action.


Why does my heat pump cool but does not heat?

You may think your heat pump is cooling, but it’s not. A heat pump cools but does not heat when there is a malfunction. A faulty compressor, low refrigerant levels, or a malfunctioning reversing valve can cause this issue.

Why does my heat pump not blow air?

If a heat pump is not blowing air, it could indicate a problem with the unit. Common causes could be a faulty fan motor, a malfunctioning thermostat, or a blocked air filter.


Heat pumps are used by millions of homeowners and renters around the world every day. They’re sometimes used for comfort, while others need them to survive. Following the suggestions throughout this article will prevent your heat pump from having a shortened life.

Here’s a quick recap of the post:

  • Small repairs, including clogged filters, frozen coils, and blocked vents, can be why your heat pump isn’t working as it should.
  • If you’re unfamiliar with electrical work, call a professional for a quote and a warranty.
  • Replacing a heat pump can cost up to $5,100, while repairing it can cost as little as $400.



Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.