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Why Is My Heat Pump Blowing Cold Air?

Why Is My Heat Pump Blowing Cold Air?

So it’s midwinter and you notice that your heat pump is blowing cold air. Now you’re wondering what’s going on.

Well, there are 3 scenarios that might explain what’s happening with your heat pump:

  1. The heat pump isn’t actually blowing cold air, it just feels like it
  2. Your heat pump is blowing cold air because it’s in “defrost mode”
  3. Something’s actually wrong with the unit and requires a professional

Not sure which of the above describes your situation? Don’t worry. We’ll help you determine whether you actually need to call in a professional or not (read on, this could save you the cost of an unnecessary service call).

Already know you need professional heat pump repair? Just contact us and we’ll send over a tech immediately.

Your heat pump might not actually be blowing “cold” air

If it’s a particularly cold day or night, your heat pump might just be blowing air that’s cooler than your body temperature, making you think it’s cold.

You see, a heat pump heats your home by moving heat from the outdoor air into your home. But as it gets colder, and your heat pump can’t pull as much heat in from the outdoor air, the air coming from your vents drops slightly in temperature. 


How an air source heat pump pulls heat in from the outdoor air.
Source

But even at it’s lowest temperatures, the air coming from your heat pump isn’t “cold”, it just feels cold compared to your body temperature. 

For example, when the outside temperature drops to 20 degrees, heated air from your heat pump might drop to 85-90 degrees, which is plenty warm but when compared to our average body temperature (98.6), 85 degree air can feel cold.

Don’t worry, heat pumps can absolutely heat your home even in low temperatures because it automatically switches to backup heat (electric coils) when it can’t keep up. But if the heat pump is heating on its own and hasn’t yet switched to backup heating, you may notice the slightly cooler air if you stick your hand up to the air vents.

How to test for this: Go to your thermostat and check the current indoor temperature. After 30 minutes, check the temperature again. Is your home getting warmer? If so, your heat pump is blowing warm air that just feels cold to you.

Your heat pump might be in “defrost mode”

When in defrost mode, a heat pump may blast cold air from its vents for 1 or 2 minutes (before the backup heat kicks in).

So what’s defrost mode? And why does it make your heat pump blow cold air?

Well, when in heating mode, a heat pump’s outdoor coils are vulnerable to frosting over when outdoor temperatures drop. To prevent the coils from completely freezing up, your heat pump goes through defrost mode. 


Frost on heat pump coils before going through defrost mode.
Source

Defrost mode basically means your heat pump temporarily switches to cooling mode. This forces the outdoor coils to heat up, melting any frost or ice that has built up. And because the heat pump switched to cooling mode, it will blow cold air into your home for a few minutes.

How to test for this: Go outside and watch your outdoor unit. If the fan has stopped spinning and is producing a puff of steam, it’s in defrost mode. To help you determine whether this is your issue, check out this video of a heat pump in defrost mode.

Something might actually be wrong with your heat pump

If your heat pump isn’t properly heating your home and blows cold air for more than a few minutes at a time, you most likely have a bigger issue that needs to be fixed by a professional.

Some common heat pump problems that would cause the unit to blow cold air include:

  • Refrigerant leak. Only a licensed HVAC tech should repair a refrigerant leak. In fact, refrigerant is so dangerous to you and your system that the EPA requires by law that a certified professional handle this job.
  • Bad reversing valve. The reversing valve is responsible for reversing the flow of refrigerant. So if this part is faulty, you’ll most likely be stuck in cooling mode. Because it is a complicated and very crucial part of your heat pump, we suggest leaving this to a professional.
  • Outdoor unit is frozen due to faulty components. If your outdoor unit is frozen and won’t defrost, even after several defrost modes, there are several things that could be causing this. We suggest letting a professional inspect your system so that they can accurately pinpoint the problem quickly.
  • Heat pump is losing efficiency (needs servicing). Your heat pump should undergo professional maintenance at least once a year. This will cut down on costly repairs and keep your unit living longer. If you haven’t had your heat pump maintained recently, we suggest getting a heat pump tune-up to keep it efficient and blowing warm air.

Need heat pump repair in Minneapolis-St. Paul?

If your heat pump is blowing cold air and isn’t heating your home, we’re here to help.

Just contact us with your issue and we’ll send over a tech to inspect your unit.

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Categories: Heating