Why Is My Heat Pump Not Cooling on Hot Days?

A heat pump not cooling on hot days usually has poor airflow, dirty coils, low refrigerant, or a thermostat setting issue. The most common cause is a clogged filter or an outdoor coil coated with dust that blocks heat release. In desert heat, even a small airflow drop can spike pressures and shut cooling down. Our technicians regularly service the Las Vegas valley, including homes in Winchester.

Check these before calling:

• Set thermostat to Cool, lower the setpoint, and use Auto for the fan.
• Replace the filter; with power off, rinse the outdoor coil and clear debris.
• If you see ice or a tripping breaker, turn cooling off, use Fan Only, then call.

If cooling doesn’t return within an hour, schedule a diagnostic to protect the compressor. <br/> Updated: 2026-04-02 <br/> Need help in Winchester, NV? Call (702) 710-9106 or book online.