Why Is My Heat Pump Not Blowing Warm Air?

HVAC Professionals Guide You Through Common HVAC Problems You Might Find With Your Heat Pump

A heat pump is an essential part of maintaining your home comfort, especially in climates that experience both warm and cold weather throughout the year. Heat pumps work by transferring heat from the outside air to warm your home in the winter and reversing the process to cool your home in the summer, not creating hot or cold air.

But what happens when your heat pump stops blowing warm air on a chilly day? There are several reasons why this might occur, and understanding these can help you decide whether a simple DIY fix can solve your common HVAC problems or if professional HVAC servicing is required.

The Heat Pump Is In a Defrost Cycle

One of the most common reasons a heat pump might blow cooler air is because it has switched into defrost mode. This occurs when the outdoor unit senses ice or frost build-up on the coils and temporarily reverses its function, directing the heat energy to warm the equipment to melt the frost.

If your heat pump is producing cold air, wait 10 to 15 minutes. It’s possible your heat pump is in its standard defrost cycle, a normal part of the heat cycle process, and it does not require HVAC servicing. This process usually only lasts for a few minutes.

What to do: If the heat pump gets stuck in defrost mode for an extended period, it may be a sign that something is wrong, and it’s time to call an HVAC service professional.

Your Air Filters Are Dirty

Air filters successfully trap dust, dirt, and other particles to improve indoor air quality and system efficiency, but if they are too dirty or blocked, your heat pump can stop working properly or blow cooler air. This is due to the airflow restriction on the compressor in your heat pump. You can find air filters on your system’s return registers, in the system’s air handler cabinet, or both.

What to do: Clogged filters are a common HVAC maintenance issue that can be easily rectified by regularly changing or cleaning your air filters. In homes with single residents and no pets, change the air filter at least every 90 days. In homes with multiple residents or pets, change them every month. Clean air filters will improve airflow, allowing your heat pump to blow warm air more effectively.

Your Thermostat Settings Are Incorrect

Sometimes, the issue isn’t with the heat pump itself but with your thermostat settings. If the thermostat is set to the wrong mode or temperature, your heat pump may not blow warm air as expected. For instance, if your programmable thermostat that’s set to “cool” mode or if the temperature is set too low, the heat pump will not provide the warmth you need.

What to do: Double-check your programmable or smart thermostat settings to ensure it’s in “heat” mode and that the temperature is set to a comfortable level. The World Health Organization (WHO) recommends a minimum home temperature of 64°F to 70°F for children, elderly people, or other vulnerable populations.

After your thermostat is set properly, allow up to one hour for your heat pump to start warming your home.

The Refrigerant Levels Are Low

Heat pumps use refrigerant to transfer heat from outside to inside in a heat exchange process that powers the system. If the refrigerant levels are too low due to a leak or poor maintenance, the heat pump will struggle to warm your home. This is a more serious issue, as low refrigerant levels can not only affect heating performance but also cause damage to the compressor.

What to do: Low refrigerant is a common HVAC problem that requires a professional technician to diagnose and fix. Signs of a leak might include hissing or bubbling sounds, pooling liquid, frozen evaporator coil, or a rise in humidity levels in your home. If you suspect a refrigerant leak, call a company that specializes in servicing HVAC problems, as handling refrigerants can be dangerous and requires a trained professional.

Your Outdoor Unit Is Blocked or Frozen Over

Because your heat pump is installed outdoors, leaves, dirt, ice, or snow can block it, making it inefficient or stop working altogether.

What to do: Inspect your outdoor unit and make sure it’s free of debris, ice, and snow. Clear any obstructions to ensure proper airflow around the unit. If it regularly freezes over, it could indicate a deeper problem with the defrost cycle, which will require contacting a professional HVAC service.

Your Heat Pump Compressor Is Broken

The compressor is the heart of your heat pump. Its job is to circulate refrigerant and facilitate heat transfer. If the compressor fails, the heat pump will be unable to blow warm air, and the entire system may shut down.

Electrical issues, refrigerant problems, or general wear and tear over time can cause compressor failure.

What to do: If you suspect a faulty compressor, call a local company that specializes in HVAC service. Compressor repair or replacement is a complex task best left to professionals.

You Air Ducts Are Leaking

If your heat pump is blowing cold air, the problem may not be with the heat pump itself, but with your ductwork. Leaky or damaged air ducts allow warm air to escape before it reaches your living space, resulting in cooler air being blown into the home. This not only reduces heating efficiency but can also increase energy costs as the heat pump works harder to compensate for the lost heat.

What to do: If your heat pump seems to be in good working order, check for increased dust around your home, or signs of inefficient and inconsistent heating across your home, as these might indicate a duct leak. Have a professional HVAC service technician inspect your ductwork for leaks or damage. Sealing your ducts will likely improve airflow and your home’s temperature.

Heat Pump Issues? Trust Your Local Reputable HVAC Service Company For Repairs and Installation

A qualified HVAC service technician can quickly restore comfort in your home and ensure your system can run efficiently and effectively throughout the year, including when your heat pump stops blowing warm air.