No Heat from Heat Pump

On this page

Quick answer
Confirm the symptom
Tools and prep
Step-by-step troubleshooting
Common causes table
Parts matching
When to call a pro
FAQ
Related guides

Quick answer

Check the thermostat settings, ensure the power is on, and inspect the emergency heat setting. If the issue persists, test the air filter and outdoor unit for obstructions.

Confirm the symptom

Heat pump is not producing heat
Thermostat shows heat call but no warm air
Outdoor unit is not running during heating mode

Tools and prep

Screwdriver set
Thermal imaging camera (optional)
Vacuum cleaner with brush attachment
Multimeter
Safety gloves and goggles
Owner's manual for the heat pump

Step-by-step troubleshooting

Check Thermostat Settings
Do: Verify the thermostat is set to 'Heat' and the desired temperature is higher than the current room temperature.
Observe: Thermostat is in 'Heat' mode and temperature is set correctly.
Means: Thermostat settings are correct.
Next: If settings are correct, proceed to the next step.
Inspect Emergency Heat Setting
Do: Check if the emergency heat setting is activated on the thermostat.
Observe: Emergency heat is either on or off as needed.
Means: Emergency heat setting is properly configured.
Next: If emergency heat is off, turn it on and wait 10 minutes to see if heat is produced.
Check Power Supply
Do: Ensure the heat pump's circuit breaker is on and the outdoor unit's power switch is in the 'On' position.
Observe: Power is supplied to both indoor and outdoor units.
Means: Power supply is confirmed.
Next: If power is off, restore it and wait for the system to start.
Inspect Air Filter
Do: Remove and examine the air filter for dirt or blockage.
Observe: Air filter is clean or dirty.
Means: A dirty air filter can restrict airflow and affect heating performance.
Next: If the filter is dirty, replace or clean it and check if heat is restored.
Check Outdoor Unit for Obstructions
Do: Inspect the outdoor unit for snow, ice, or debris that may be blocking airflow.
Observe: Outdoor unit is clear of obstructions or has blockages.
Means: Obstructions can prevent the heat pump from operating properly.
Next: If obstructions are found, clear them and wait to see if heat is produced.
Test Fan Operation
Do: Check if the indoor fan is running when the heat pump is in heating mode.
Observe: Indoor fan is running or not.
Means: A non-operating fan may indicate an electrical issue or a faulty motor.
Next: If the fan is not running, consult an HVAC professional.
Verify Refrigerant Levels
Do: Use a multimeter to check the refrigerant pressure (if you have experience) or look for signs of refrigerant leaks.
Observe: Refrigerant pressure is within the normal range or shows a leak.
Means: Low refrigerant can prevent the heat pump from producing heat effectively.
Next: If refrigerant is low, contact an HVAC technician for recharging.

Common causes

Cause	Likelihood	Difficulty	Part often needed
Incorrect Thermostat Settings The thermostat may be set to 'Cool' or 'Off' instead of 'Heat'.	Common	Easy	None
Dirty Air Filter A clogged air filter restricts airflow, reducing heating efficiency.	Common	Easy	Air Filter
Power Supply Issues A tripped circuit breaker or a switched-off power switch can prevent the heat pump from operating.	Common	Easy	None
Blocked Outdoor Unit Snow, ice, or debris can block the outdoor unit's airflow, affecting heat production.	Common	Easy	None
Faulty Emergency Heat Setting The emergency heat setting may be improperly configured or malfunctioning.	Sometimes	Easy	Thermostat
Non-Operating Indoor Fan A faulty fan motor or electrical issue can prevent the indoor fan from running.	Sometimes	Medium	Indoor Fan Motor
Low Refrigerant Levels Low refrigerant can prevent the heat pump from transferring heat effectively.	Sometimes	Hard	Refrigerant
Faulty Defrost Cycle A malfunctioning defrost cycle can cause the outdoor unit to ice over, reducing heat production.	Rare	Hard	Defrost Control Board
Compressor Issues A faulty compressor can prevent the heat pump from generating heat.	Rare	Hard	Compressor

Parts matching

If your troubleshooting leads you to replace parts, here are common parts for 'no heat from heat pump' issues:

Air Filter – Replace if dirty or clogged.
Thermostat – Replace if settings are not responding or if there is a malfunction.
Indoor Fan Motor – Replace if the fan is not operating.
Refrigerant – Recharge if levels are low (must be done by a professional).
Defrost Control Board – Replace if the outdoor unit is icing over and not defrosting.
Compressor – Replace if it is faulty and not generating heat.

Always consult an HVAC professional for refrigerant-related issues and compressor replacements due to the complexity and safety requirements.

When to call a professional

The heat pump still doesn't produce heat after checking all settings and clearing obstructions.
You detect a refrigerant leak or smell burning.
The indoor fan is not running and you suspect an electrical issue.
The outdoor unit is icing over and not defrosting properly.
You hear unusual noises from the heat pump, such as grinding or squealing.
The system is making no noise at all when it should be operating.
The issue persists for more than a day after initial troubleshooting.

FAQ

Why is my heat pump not producing heat even though it's on?

This can be due to incorrect thermostat settings, a dirty air filter, power supply issues, or a malfunctioning component like the fan or compressor.

How do I know if my heat pump needs refrigerant?

Signs include reduced heating performance, ice buildup on the outdoor unit, or hissing sounds indicating a leak. Refrigerant issues require a professional technician to recharge or repair the system.

Can a dirty air filter cause a heat pump to stop producing heat?

Yes, a clogged air filter restricts airflow, which can significantly reduce the heat pump's efficiency and prevent it from producing adequate heat.

What is emergency heat, and when should I use it?

Emergency heat is a backup heating source that activates when the heat pump is not functioning. Use it only when the heat pump is not working and as a temporary solution until it is repaired.

Why is my heat pump's outdoor unit not running?

This could be due to a tripped circuit breaker, a faulty power switch, or a malfunction in the outdoor unit's motor or control board.