The Dirty Squirrel Cage Blower
The blower wheel in your furnace or air handler is a centrifugal 'squirrel cage' fan featuring dozens of precision-curved aluminum blades. When dirty air bypasses poor filters, dust, pet dander, and cooking grease deposit directly into the concave cups of these blades.
The 30% Efficiency Drop
HVAC engineering tests show that a layer of dirt just 1/16-inch thick on the curve of blower blades can reduce airflow by up to 30%, forcing the motor to run longer, overheat, and consume significantly more electricity.
Symptoms Your Blower Wheel Needs Cleaning
- Weak airflow from registers despite a brand new clean filter.
- Unusual humming, droning, or high-vibration noise from the furnace compartment.
- Furnace short-cycling on the high-limit temperature sensor during cold spells.
About ClariSelect Editorial & Research Standards:
Sizing measurements, static pressure curves, and filtration ratings referenced across our educational guides are compiled from published ANSI/ASHRAE Standard 52.2 engineering data, AHAM AC-1 verified ratings, and manufacturer technical documentation. ClariSelect provides objective editorial research and analysis with zero sponsored placements.