BACKMAR 11, 2026
Realizing your heat pump won't turn on can cause an immediate spike in stress, especially if the temperature inside your home is dropping. However, a silent heat pump does not automatically mean you are facing a major repair.
Looking for more guidance? Take a look at our Repairs overview.
Heat pumps are designed with built-in safety mechanisms. Often, they will shut themselves down to prevent internal damage if they detect a simple airflow restriction or a minor power interruption. Before you call a technician, there are several straightforward, safe steps you can take to diagnose and potentially resolve the issue yourself.
When a heat pump fails to start, you will typically notice one or more of the following:
Here is a step-by-step guide to tracking down the root cause and getting your heat pump running again.
Stand in front of your thermostat. Is the display completely blank? If so, the system simply might not be receiving the command to turn on.
Gently pull the faceplate off the thermostat to expose the battery compartment. Remove the old batteries and insert two new AA batteries, making sure to match the positive and negative markings. Reattach the faceplate until it clicks into place, and wait about 60 seconds for the device to reboot. If the thermostat still does not power on, it is time to stop and call a professional, as there may be a wiring issue.
If your thermostat is powered on, ensure it is actually asking the system to heat your home. Press the mode button and select "Heat." Then, raise the set temperature at least 5 degrees Fahrenheit above the current room temperature. Listen for a click from the thermostat, and wait up to 3 minutes. Heat pumps have built-in delays to protect their compressors.
If the system starts, you are good to go. If it remains off, move to the next step.
Sometimes, a minor electrical surge causes the heat pump's circuit breaker to trip. Locate your home's electrical panel (often in a basement, garage, or utility closet). Look for the breaker labeled "Heat Pump" or "HVAC."
Even if it does not look fully tripped, push the breaker firmly to the "Off" position. Wait 10 seconds, then push it firmly back to the "On" position. Return to your thermostat and wait another 3 minutes. If the heat pump still does not start, leave the breaker on and proceed to check the outdoor unit.
(Note: If the breaker trips immediately after you reset it, stop. Do not reset it again. Call a licensed HVAC technician to diagnose the electrical fault.)
Walk outside to your heat pump condenser. Carefully remove any leaves, snow, or debris resting on the top or sides of the unit by hand.
Next, look for thick ice on the internal coils or fan blades. If the unit is encased in ice, go back inside and set your thermostat to "Emergency Heat." This utilizes your backup heating strips while allowing the outdoor unit to thaw. Wait up to 2 hours for the ice to melt. Once the unit is clear, switch the mode back to standard "Heat" and wait 3 minutes.
A severely clogged filter is a very common reason for a system shutdown. Go indoors to your air handler or return-air grille and slide the filter out.
Hold the filter up to a bright light or a window. If you cannot see any light passing through the material, the filter is too dirty and is restricting airflow. Purchase a new filter in the exact same size. Turn off your HVAC system at the thermostat, slide the new filter in (ensuring the airflow arrows point toward the equipment), and close the panel. Turn the thermostat back to "Heat" and wait 3 minutes.
Tracking filter changes can be tedious, but you can log your filter sizes and replacement schedule in your Casa profile so you never have to guess when it's time for a fresh one.
Safe to try yourself:
When to stop and call a professional:
At this point, you need a licensed HVAC technician to diagnose potential issues with the control board, sensors, or refrigerant levels.
Troubleshooting this issue yourself requires very little time or money:
A heat pump that won't turn on is frequently easily resolved. By methodically checking the thermostat power, confirming your temperature settings, resetting the breaker, clearing the outdoor condenser, and verifying your air filter is clean, you can rule out the most common culprits. If the system still refuses to operate after these basic checks, it is time to bring in an expert to handle internal electrical or mechanical faults safely.
For more guidance on maintaining your home's critical systems, download the Casa app. Casa provides you with an always-on home advisor to help you track maintenance schedules, understand your home's specific needs, and manage repairs with quiet confidence.
