How to check heat pump airflow and diagnose poor performance
If rooms feel inconsistently heated or cooled, the problem is often airflow rather than the heat pump itself. This walkthrough helps you identify blocked vents, closed dampers, and dirty filters before calling a technician.
What you'll learn
- How to use a tissue or your hand to test airflow at supply and return vents
- How to identify closed or partially closed dampers in a ducted system
- How to tell if the problem is the filter, the ducts, or the equipment
Step by step
- Check your air filter first. A clogged filter is the most common cause of reduced airflow. Pull the filter and hold it up to a light. If you can't see light through it, replace it before doing anything else.
- Walk every supply and return vent. Open every register in the house and confirm nothing is blocking them -- furniture, rugs, or stored items. Hold a tissue near each supply vent to confirm you feel airflow.
- Check for closed or partially closed dampers. Some registers have a lever or wheel that adjusts the damper. Make sure all are open. In older San Diego homes with zoned duct systems, check the zone dampers in the attic or utility closet.
- Listen at the air handler. Stand near the indoor air handler or return vent and listen for the blower motor running. A blower that hums but does not move air may have a failed capacitor or belt.
- Compare room temperatures. If certain rooms are consistently much hotter or colder than others despite open vents, the issue may be duct leakage or undersized duct runs -- both of which need a technician.
In San Diego homes with bonus rooms or add-ons, poor airflow in those spaces is common because the original duct system was not sized for the extra square footage. A ductless mini-split is often the better long-term solution for those areas.
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