Lennox Explains the Heat Pump Defrost Cycle
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Lennox consumer education covers normal 5-15 minute defrost, steam from the outdoor unit, auxiliary heat, and when frequent defrost means call a pro—useful when Tampa Bay cold fronts arrive.
Normal, not broken
Lennox explains that frost on the outdoor coil reduces efficiency, so the heat pump briefly reverses to melt ice. Homeowners may see steam, hear a whoosh, feel a brief indoor temperature dip, or notice auxiliary heat—typically for about 5 to 15 minutes.
It can defrost above freezing
Coil surface temperatures can be colder than outdoor air, so defrost in the 40s F is not unusual in humid weather. Systems may check conditions on a schedule (often discussed as roughly 30-90 minute intervals) and only run defrost when sensors require it.
When to call The Cooling Experts
Lennox notes that excessive or very long defrost can point to dirty coils, sensor issues, or low refrigerant. Clear debris around the outdoor unit; leave refrigerant diagnosis to EPA Section 608 certified technicians. We service Lennox heat pumps locally.
Sources & governing bodies
Educational references only. The Cooling Experts are an independent contractor. Verify model ratings in the AHRI Directory and current program rules on official sites.
Related service: Warm Air
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