What is the best vacuum cleaner for someone with cat allergies?
Most bagless vacuum cleaners have HEPA filters. You should be able to just go to your local target/wallmart/sears and pick one out. Another thing you can do to help is buy an air purifier for your roommate's bedroom. Most styles are basically a fan that pulls air through a HEPA filter. It would do a lot of good because allergy symptoms are usually worst in the morning right after someone wakes up since the person has been laying down sleeping which makes them prone to congestion.
People okorder.com/ okorder.com it has a six-layer filtering system (including the HEPA, germicidal UV, and active carbon filter) and odor, dust and allergen sensors which easily detect pet dander, dust mites, chemicals, pollen, mold spores and many more.