Heat Pump Running Constantly / Not Cycling Off

Common Symptoms

You might be experiencing this problem if you notice any of these signs:

• Heat pump runs 24/7 without stopping
• Never reaches thermostat set temperature
• Outdoor unit constantly running
• Indoor fan never turns off
• High electricity bills
• Slight temperature improvement but never comfortable
• Runs constantly even in mild weather
• Auxiliary heat running all the time
• No cycling on and off like it used to
• Thermostat shows correct temperature but unit won't stop

Step-by-Step Diagnosis

Follow these steps to identify the exact cause of your problem:

1. Check thermostat temperature setting vs. actual room temperature
2. Verify thermostat is not set to "Fan ON" mode (should be AUTO)
3. Check outdoor temperature - extreme cold affects performance
4. Inspect air filter for severe clogging
5. Verify all indoor vents are open and unobstructed
6. Check thermostat heat setting - if set unrealistically high
7. Note if auxiliary heat is running constantly
8. Verify thermostat is reading room temperature accurately
9. Check if heat pump sized appropriately for home size
10. Look for open windows or doors causing heat loss
11. Inspect for unusual heat loss (poor insulation)
12. Verify compressor is actually running, not just fan

Most Common Causes (Ranked by Likelihood)

DIY Solutions

Step-by-Step Instructions:

1. Check thermostat fan setting - change from ON to AUTO
2. Verify thermostat heat setting is reasonable (68-72°F)
3. Replace air filter immediately if clogged
4. Close any open windows or doors
5. Check all vents are open throughout house
6. Verify thermostat reading matches actual room temperature
7. Place separate thermometer near thermostat to verify accuracy
8. Set thermostat 2-3 degrees lower and monitor if unit cycles off
9. Check outdoor temperature vs. heat pump specifications
10. If below 25°F outside, switch to emergency heat temporarily
11. Inspect home for drafts around windows and doors
12. Seal obvious air leaks with weatherstripping
13. Check attic insulation depth (should be 12-15 inches)
14. Monitor system for 24 hours after filter change
15. Calculate if heat pump tonnage matches home square footage

When to Call a Professional

Don't attempt DIY repairs if you experience any of these situations:

• Heat pump runs constantly even in mild weather (50°F+)
• Never reaches set temperature despite running 24/7
• High energy bills (50%+ increase from previous year)
• Heat pump is less than 3 tons for 2,000+ sq ft home
• Refrigerant leak suspected (ice on lines, hissing sounds)
• Auxiliary heat runs constantly in moderate temperatures
• Heat pump more than 12 years old with declining performance
• Home has extreme temperature variations room to room
• Recent home addition but same heat pump
• Blower motor sounds strained or weak

Prevention Tips

Stop this problem before it starts with these preventive measures:

• Have professional load calculation done before installing heat pump
• Size heat pump correctly for home - typically 1 ton per 500-600 sq ft
• Replace air filters monthly during heavy use periods
• Seal air leaks around windows, doors, and attic penetrations
• Add attic insulation to R-38 or higher in cold climates
• Install programmable thermostat with realistic temperature settings
• Consider backup heating for extreme cold days below 15°F
• Schedule annual maintenance to maintain refrigerant levels
• Keep outdoor unit clear of snow and debris
• Use ceiling fans to improve air circulation and reduce runtime