Keep your air purification system running its best by replacing the filter every 6 months. When it's time to replace the air filter in your PureAir air purification system, trust the filter replacement to keep your air clean, clear, and breathable. Designed to keep your air clean, this air filter is rated at MERV 11 efficiency. This means it can filter out particles in the air as small as 0.3 microns. Breathe easier in your home by replacing an old or dirty air filter with this air purifier filter replacement.