Why Your Heat Pump Is Not Heating and How to Fix It

When your heat pump stops heating, it can quickly turn a comfortable home into a chilly one. Heat pumps are reliable, energy-efficient systems, but like any equipment, they can run into issues. Understanding why your heat pump is not heating and knowing how to troubleshoot it can save you time, money, and discomfort. This guide walks you through common causes and practical steps to get your heat pump working again.

Trained and certified Intelligent Air technician evaluating a heat pump in Tallahassee FL

Check the Thermostat Settings

Start by verifying your thermostat settings. Sometimes the problem is as simple as the thermostat being set incorrectly.

• Make sure the thermostat is set to heat mode, not cool or fan.

• Check the temperature setting. It should be higher than the current room temperature.

• If your thermostat uses batteries, replace them to ensure proper function.

• Reset the thermostat by turning it off and on again to clear any glitches.

  
  

If the thermostat is faulty or unresponsive, it might need professional repair or replacement.

Inspect the Air Filters and Vents

Dirty air filters and blocked vents reduce airflow, causing the heat pump to struggle with heating.

• Locate the air filter and check for dust or debris.

• Replace or clean the filter if it looks clogged. Filters should be changed every 1-3 months depending on use.

• Ensure all supply and return vents are open and unobstructed.

• Clear any furniture, curtains, or objects blocking airflow.

  
  

Good airflow helps the heat pump operate efficiently and maintain consistent warmth.

Look for Ice or Frost on the Outdoor Unit

A common reason heat pumps stop heating is ice buildup on the outdoor unit.

• Inspect the outdoor unit for frost or thick ice on the coils.

• A thin layer of frost is normal in cold weather, but heavy ice can block heat transfer.

• If you see ice, turn off the heat pump and let the ice melt naturally.

• Check if the defrost cycle is working. The defrost mode should activate automatically to clear ice.

• If ice keeps forming, the defrost sensor or control board may be faulty.

  
  

Avoid manually chipping ice off the unit, as this can damage the coils.

Examine the Refrigerant Levels

Low refrigerant levels prevent the heat pump from heating properly.

• Refrigerant leaks cause pressure drops and reduce heat transfer.

• Signs of low refrigerant include poor heating performance and ice buildup.

• Only certified technicians should check and recharge refrigerant due to environmental and safety regulations.

• If you suspect a leak, schedule a professional inspection promptly.

  
  

Maintaining correct refrigerant levels ensures your heat pump runs efficiently.

Check the Outdoor Temperature and Heat Pump Capacity

Heat pumps work best in moderate climates but can struggle in extreme cold.

• When outdoor temperatures drop below freezing, the heat pump may need supplemental heating.

• Some models include electric resistance heaters to support heating in very cold weather.

• If your heat pump is undersized for your home or climate, it may not keep up during cold spells.

• Consider a backup heating source or upgrading to a model designed for colder climates.

  
  

Understanding your heat pump’s limits helps set realistic expectations for heating performance.

Inspect Electrical Components and Breakers

Electrical issues can cause the heat pump to stop heating.

• Check your circuit breaker panel for tripped breakers related to the heat pump.

• Reset any tripped breakers and see if the system restarts.

• Look for blown fuses or loose wiring connections.

• If you notice burning smells or unusual noises, turn off the system and call a professional.

  
  

Electrical repairs should be handled by qualified technicians to avoid hazards.

Clean the Coils and Clear Debris

Dirty coils reduce heat exchange efficiency.

• Both indoor and outdoor coils can accumulate dirt, dust, and debris.

• Clean the coils gently with a soft brush or coil cleaner.

• Remove leaves, grass, or snow around the outdoor unit to maintain airflow.

• Regular coil cleaning improves heating output and extends equipment life.

  
  

Schedule coil cleaning at least once a year or more often in dusty environments.

Reset the Heat Pump System

Sometimes, a simple reset can fix minor glitches.

• Turn off the heat pump at the thermostat and the breaker.

• Wait 5-10 minutes before turning everything back on.

• This can clear error codes and restart the system’s control board.

  
  

If problems persist after resetting, further troubleshooting or professional help is needed.

When to Call a Professional

If you have tried these steps and your heat pump still does not heat, it’s time to contact a qualified HVAC technician.

• Persistent ice buildup or refrigerant leaks

• Electrical problems beyond breaker resets

• Faulty defrost controls or sensors

• Compressor or motor failures

  
  

Professional service ensures safe, accurate diagnosis and repair.