Lasko 21" Galaxy Box Fan with Weather-Shied Motor and 3 Speeds, 4733, White, New

This is the setup I did. https://www.walmart.com/ip/Lasko-21-Galaxy-Box-Fan-with-Weather-Shied-Motor-and-3-Speeds-4733-White-New/10553592?classType=REGULAR&athbdg=L1300&from=/search Then select a 21-in filter that matches your needs. Sent my child to Walmart and they picked the stuff up in 10 minutes. This is a multi pack so cost per unit is relatively small. Merv 13 filter multi pack To help you select the best filter to meet your needs, you might want to learn more about Merv rating. Merv rating So this also applies to your furnace. Make sure that you have a furnace filter that supports your needs. Caveat! I am actually unable to do this because my furnace is old enough that if I put on a high Merv rated filter it will put too much strain on the furnace engine. But ideally you want to do this because then it works whether you have your heater or your AC on. You can even just set your thermostat to fan only to run constantly to be constantly filtering your air. But make sure that you change your furnace filter regularly! I have been so stupid and get sidetracked and miss my reminder, only to find my furnace filter is black because I didn't change it timely. So for me the box fan solution is cheaper in the long run. It can be moved from room to room as needed. And I don't have to run the risk of ruining my furnace. A $20 box fan is a lot cheaper than a $20,000 furnace replacement.