A defrost cycle is a heat pump's automatic routine for clearing frost from its outdoor coil during heating. When sensors detect frost build-up, the system briefly reverses to send warm refrigerant through the outdoor coil, stops the outdoor fan, melts the frost, then returns to heating. Rising steam from the outdoor unit during defrost is normal.
Why it matters to you
Fraser Valley winters sit near freezing with high humidity, which is exactly when frost forms fastest, so heat pumps here defrost more often than in drier climates. Knowing what a normal defrost looks like saves an unnecessary call, and spotting an abnormal one early protects the coil.
Practical guidance
Keep clear space around the outdoor unit and make sure meltwater can drain away from the base. Call for service if the coil stays encased in solid ice, defrost runs almost continuously, or backup heat seems to run non-stop.