How often should I change my filters?

For air conditioners and furnaces, filters should be changed once a month. For air purifiers, they usually need to be changed every six months, and require very specific filters. For air conditioners and furnaces, regular pleated filters work well. Don't buy the least or the most expensive filters, but something in the middle. Expect to pay $5-6 per filter. You can buy them in bulk to save money. Make sure they are the correct size.

-Rich