They stick to upholstery and carpets, hide in the very back corners and swirl in the air when vacuuming. Animal hair is difficult to catch for conventional vacuum cleaners with a bag. Bagless vacuum cleaners with a water filter provide a remedy, they also clean the air. What is a matter of concern for many pet lovers is the fact that the risk of developing pet hair allergy is very high. The allergens sit primarily on the animal skin and fur. The only true prevention: The person who loves his pet and his own health vacuums regularly with water and cleans the air.