Westinghouse
Airflow restriction or duct resonance
Furnace produces a high-pitched whistling or howling noise during operation.
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Possible Causes
Filter too restrictive or partially blocked, Undersized return air duct, Closed or partially closed supply registers, Air leaks around furnace cabinet or filter rack
How to Fix / Troubleshooting
Steps:
- Replace the air filter with a clean filter of appropriate MERV rating; avoid overly restrictive filters unless the duct system is designed for them.
- Open all supply and return registers fully.
- Inspect around the furnace cabinet and filter rack for gaps where air is being sucked in; seal with HVAC foil tape or approved gasketing.
- If whistling persists, consult an HVAC contractor to evaluate duct sizing and static pressure.
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Repair Difficulty
Easy
2/5
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