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Do-it-yourself projects and plans for anyone who can swing a hammer.

HEPA Filters in Forced-air Furnaces and Air Conditioning Systems

Our recent article about energy-recovery ventilators (Ventilate Your Home with Minimal Energy Loss) stated that using a “true high-efficiency particulate air (HEPA) filter” in your forced-air heating or air conditioning system would reduce allergens more effectively than regular filters. But reader John Alderman pointed out that this could be dangerous. So we went to the experts for their advice.

Mel Mossman, Chief Mechanical Engineer at RS Means, helps us explain:

We asked the Environmental Protection Agency, too. Here’s an official statement from them: