We have a major polluter in our area that simply pays the fines and keeps on contaminating our air and water. We were actually ready to sell our home and move out of beautiful Oregon. Our house is 2400 square feet with vaulted ceilings, three bedrooms, and a loft. We purchased five of the Bluair plus machines, two for downstairs and one for each bedroom. The machines run constantly. The filters last about eight months. Quiet and effective. They literally saved us and our home.