Ecobee ecobee4 Smart Thermostat HEAT-FAIL Error Fix: Heat Not Reaching Set Temperature

Error code HEAT-FAIL on the Ecobee ecobee4 Smart Thermostat means: Heat Not Reaching Set Temperature. The thermostat has been calling for heat but the home temperature is not rising toward the setpoint — the HVAC equipment may not be responding, the furnace may have a fault, the heat pump compressor may be locked out, or the system may be undersized for the heating load

The most successful fix is "Test Furnace Ignition and Heat Pump Compressor Operation" (hard difficulty, ~90 minutes). Estimated DIY cost: $0-$30. HomeMD has 2 community-ranked fixes for this error.

This error is rated medium severity. It should be addressed soon, but your appliance may still function in a limited capacity.

Yes — the top-ranked community fix ("Test Furnace Ignition and Heat Pump Compressor Operation") is rated hard difficulty and takes about 90 minutes. Tools needed: Multimeter, Phillips screwdriver, Flashlight, Fine grit sandpaper.

DIY cost: $0-$30. Professional repair typically costs $150-$300. Many homeowners save money by trying the top-ranked community fix first.

The Ecobee ecobee4 Smart Thermostat has 8 other known error codes, including: APP-SYNC (App and Thermostat Out of Sync), AUX-OUTDOOR (Auxiliary Heat Outdoor Temperature Alert), AUX-RUNTIME (Auxiliary Heat Runtime Alert), BLOWN-FUSE (HVAC Control Board Fuse Blown), COOL-FAIL (Cool Not Reaching Set Temperature), and 3 more.

Error code HEAT-FAIL also appears on 5 other Ecobee models: ecobee Smart Thermostat Enhanced with Radar Occupancy Sensor and Large Touchscreen, ecobee Smart Thermostat Essential with Touchscreen Display and eco+ Smart Features, ecobee Smart Thermostat Premium with Siri and Alexa Built-In, Air Quality Monitor, and SmartSensor Included, ecobee SmartThermostat with Voice Control and Alexa Built-In, ecobee3 Lite Smart Thermostat. The fix may vary by model, so check each model's specific page for tailored repair steps.