I purchased the Electrolux Harmony vacuum cleaner from AllergyBuyersClub.com a few years ago since they gave it a very good rating for best value Hepa vacuum.  It has done everything they said it would: ideal for removing dust, pet hair, and allergens from bare floors and medium carpets, lightweight and easy to use, retractable cord – love this and it never smells like you have vacuumed after using it – so it certainly must be sealed so nothing gets back out.  I recommend this vacuum for anyone who wants a great value on a Hepa sealed vacuum for under $300. By the way - shipping is free for orders $150 or more.