It seems to be a common issue people have when they are looking for their HVAC system: they can’t find the unit’s replaceable filter! The filter helps keep the air clean, and is usually found where the big return vent is. Though depending on how your HVAC system is oriented (horizontal, vertical, on ceiling) It seems the best course of action as told by these HVAC specialists is to start opening up the grates and look! It’s an easy replacement!
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