Heat Pump Not Blowing Hot Air [8 Easy Solutions]

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Is your heat pump not blowing hot air? The last thing you want to do is wake up in the middle of the night and discover that you cannot get any heat from your heat pump. There can be countless number of things that can stop your heater from blowing hot air. These include leaking or low refrigerant in your heat pump, dirt outdoor unit, leaking ductwork and many other issues we’ll discuss in this article.

Heat pump not blowing hot air

Let’s look at how a heat pump system works like for us to understand better how certain issues can affect how it works.

How Does a Heat Pump Work?

A heat pump system is an efficient way of heating your home. Unlike other heating methods, a heat pump does not generate any heat. Instead, it uses electricity to transfer heat between two environments. A heat pump works in the same way a refrigerator works.

In addition, a heat pump is used to cool your home during the cooling season and heats your home in the heating season.

To heat your home, the heat pump absorbs heat from your outdoor air and transfers it into your home using the refrigerant. It does the opposite when you need it too cool your home.

Why is My Heat Pump Not Blowing Hot Air?

If your heat pump is not heating your home, it be a sign of many things. Read on to learn about possible causes for your heat pump not blowing hot air.

1. Low Refrigerant in Your Heat Pump

Heat pump systems use electricity to pump the refrigerant into the condensation coils and the evaporation coils. If the refrigerant runs low, or if it is leaking, there won’t be cooling or heating in your system.

Low refrigerant in your heat pump could also mean there are leaks somewhere.

Solution: The best thing to do however when you think your system is running low on the refrigerant is call HVAC professionals who will come and tell what’s really happening and what to do.

2. Thermostat’s settings

You’ll be surprised to know how this solves your heat pump issues. Many homeowners overlook this possible cause.

Make sure you check that your thermostat is set to heat and not cool. It is very easy to accidently adjust your thermostat settings without even realizing it.

Does your thermostat use a battery? Another common issue that has to do with your thermostat is a low battery. A low or dying battery causes your thermostat to send wrong temperature signals to your heating system.

Solution: If your thermostat battery is low, replace it.  The battery is inexpensive and is readily found in stores.

3. Dirty or Blocked Outdoor Unit.

Usually, a heat pump installation has an indoor unit and an outdoor unit, also known as the condenser unit. The outdoor unit has coils where the refrigerant flows when absorbing heat from the outside air.

However, when the outdoor unit is covered with debris or other objects such as ice, it becomes difficult to absorb heat from the outside environment.

Solution: If your outdoor unit is dirty and covered with debris, clean it, remove grass, leaves from it. If there is snow or ice, shovel it away.

4. Heat Pump Not Blowing Hot Air: Reverse Valve Issues

The reverse valve of your heat pump is that part that you use for switching between cooling and heating mode. Usually when it is not working properly or broken, its stuck on the cooling mode. This could be the reason you feel like your heat pump is blowing cold air.

Solution: If you think the reverse valve is not working properly, a call to HVAC professional is in order.

5. Your Heat Pump is in Defrost Mode

Your heat pump will not blow hot air when it is defrosting the outdoor unit.

Sometimes temperatures can drop so low, and this can cause frost to build up on your outdoor unit. In defrost mode, the heat pump temporally goes into the cooling mode to allow the outdoor unit to warm up and melt the frost. When this is happening, you will notice cool air been blown out of your vents

Usually if there’s frost build up on your unit, you will notice puffs of steam from it and the fan won’t be running.

Solution: If your heat pump is in defrost mode, you don’t need to do anything much. Defrosting can take anywhere to 10 minutes so; you should be able to start receiving warm air in no time. If there is ice surrounding your outdoor unit, shovel t away, ice prevents your heat pump from absorbing the necessary heat.

6. Malfunctioning auxiliary Heat Strips

Heat pumps work best in non-extreme temperatures to heat your home. However, if your surrounding temperatures go far too low, your heat pump system will struggle to heat your home. That’s why they are supplemented by the auxiliary heat strips.

These heat stripes use electricity to heat up your home in conditions where your heat pump won’t do much. When the coils malfunction or the circuit breaker trips, they wont supplement your heat pump. That’s why you heat pump won’t blow hot air.

Solution. If your surrounding temperatures go below 40 degrees and your heat pump keeps blowing cold air, you may want to call a HVAC technician, he will definitely save you a day.

7. Heat Pump Blowing Cold Because Circuit Breaker Tripped

Sometimes power supply to your outdoor unit can be cut off if the circuit breaker for that unit trips.

In this case, the blower fan will continue blowing air but on cool coils, which is why you may feel cool air coming out of your vents.

Solution: If the circuit breaker for your unit outside tripped, you can reset it, and this should sort out the problem. But if you notice the breaker tripping again and again, this can be a sign that there is more to the system which definitely needs professionals to have a look. A call to HVAC experts is in order.

8. Heat Pump Not Heating: Leaky Ductwork

Air ducts transport warm air from the heat pump’s blower fan for distribution throughout your home. After time, they can have leaks between connections and even holes along them. This is especially if rodents find their way into your attic. They can cause damage to your ductwork.

Solution:  If there leaks in your ductwork and you find them, you can easily seal with off with a metallic duct tape or new pieces. Otherwise call in a HVAC technician for help.


Why isn’t my heat pump heating my house?

If your heat pump is not heating up your house, it could a sign of any of the following

  1. Low refrigerant in your Heat Pump
  2. Thermostat settings
  3. Dirty or blocked outdoor unit
  4. Your heat pump is in defrost mode
  5. Malfunctioning auxiliary Heat Strips
  6. Circuit Breaker tripped
  7. Leaky ductwork
  8. Problems with the reverse valve

What temp does a heat pump quit working?

A heat pump works best in temperatures of 40 degrees and above. Anything below that will lose efficiency. But heat pumps are also supplemented with the auxiliary heat strips so that when the temperature drops too low, the auxiliary will kick into action to warm up your air.

Should you run a heat pump 24 7?

While there is no specific limit to how long you should run your heat pump. You should always turn off your heat pump when you don’t need it to avoid wasting energy.

Why is there no air coming from vents in my house?

If there is no air coming from your vents, this could mean that your registers and vents are blocked or closed. Make sure you remove objects such as furniture, bed, dressing tables from places near the vents and registers. This is to allow air from vents to freely circulate into your home.

In case there is nothing blocking your vents or registers but still no air coming from vents, your might have leaks in your ductwork. Air could be escaping from your ductwork before making it into your home.

Other times, your blower fan may not be working. This could be due to a dead capacitor blower. Read more on what to do when your central heat is not working.

Final Thought

Now that it is wintertime, your heat pump maybe working hard to keep your home warm all the time. It can run into issues sometimes, that’s why it’s not unusual to have a heat pump not blowing hot air.

To avoid running into issues with your heat pump, make sure you have HVAC maintenance tune up at least twice a year. During tune up, let the technician check the refrigerant charge and examine all important parts of the system. Regular Maintenance will also prevent unforeseen break downs.

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