Vent Axia PureAir Home PIV Unit. PureAir Home provides pure, filtered air throughout the home. Perfect for protecting against the formation of mould and condensation throughout the entire household. PureAir Home provides whole house air purification and humidity control, operating efficiently in properties of up to 5 bedrooms (up to 150m²). Using a PIV ventilation system is ideal for reducing your energy consumption and saving you money, costing as little as £5 for and entire year of operation.