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A-1 Mechanical Blog

Why Is My Heat Pump Not Blowing Hot Air?

Your heat pump works hard to keep your home cool in the summer and warm in the winter. As a 2-in-1 HVAC system, you look forward to its ability to keep your home comfortable all year round.


That’s why in the winter, it can be extremely frustrating when a heat pump is not blowing hot air. Cold air is what you want in the summer, not the winter.

You may be wondering if your heat pump is simply failing to change from cooling to heating mode or if something else is causing the issue. Let’s look at 4 possible causes of a heat pump that’s not blowing hot air.

1. The Air Filter is Clogged

The first thing you should check when your heat pump isn’t putting out any hot air is the air filter. What was the last time you changed it or cleaned it? If it’s been more than a few months, this could very well be the culprit.

A dirty, clogged air filter will restrict how much air enters the heat pump to be heated. When there’s not enough airflow, your heat pump will struggle to put out hot air in the winter and cold air in the summer.  Change out the filter for a new one to see if that fixes the problem, then change it every 1-3 months.

2. The Reversing Valve is Broken

The reversing valve is the clever component that allows a heat pump to provide both heating and cooling. This valve controls the flow of refrigerant. The direction the refrigerant moves is what causes it to be able to heat and cool. 

If the valve is stuck, damaged, or broken and the heat pump is only outputting cold air, it could very well be the fault of this component. Luckily, this is a fairly easy fix for our team. We can replace the reversing valve and get the refrigerant flowing in the right direction to restore your heat pump’s ability to heat.

3. The Thermostat is Miscalibrated

Sometimes the issue isn’t with the heat pump itself. Your thermostat is the “brains” behind your HVAC system and sometimes it can develop issues such as miscalibration. 

A miscalibrated thermostat can mean the heat pump won’t run long enough to maintain the level of warmth you want. The thermostat could also lose its connection to the reversing valve, making it impossible to switch the system to heating mode.

4. A New Heat Pump Was Sized Incorrectly

Was your heat pump recently installed and this is the first time you’re using it in heating mode? Did you DIY install it or go with a company that might not have sized it correctly for your home? 

A new heat pump must be sized correctly for a home in order for it to provide enough heat to your home. A heat pump that’s undersized will struggle to provide adequate heat. If your heat pump is new, unfortunately, this could be the cause of the issue.

Contact A-1 Mechanical Heating & Cooling for your next heating service. Comfort and Character You Can Depend On

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