For maximum effectiveness, Consumer Reports advises keeping the fabric pre-filter off. The Honeywell air purifier is another effective option for removing dust, pollen, and smoke, but it's most ...

If your air quality is bad and you don’t have an air purifier, an HVAC filter taped to a box ... a useful DIY air purifier. I taped a 20-by-20-inch Honeywell FPR 9 filter to a Lasko 20 ...

It's well under $100 with low filter replacement costs, though it's most efficient for small rooms. ... Best for large rooms: Honeywell PowerPlus HEPA Air Purifier - See at The Home Depot.