Originally Posted by Artisan Fan
What does a better job from a filtration standpoint? How do you measure filtration performance?
By using a particle counter at the exhaust of the vacuum, as well as around any seams in the body. You can find plenty examples of this on youtube (though half of them are by marketing shills). Even the HEPA Dysons leak a fair amount of particulate because the air pathway leading to the HEPA filter is not sealed. That's why you always get that "vacuum" smell even with a fresh cannister. People have gotten so used to it that they either don't even realize it exists, or just think that's how vacuums smell. To put in in perspective, I am totally comfortable sticking my face two inches away from my Miele Jazz's exhaust. I smell absolutely nothing, and particle counters actually read 0 parts. If you open it up, Miele actually has rubber seals, o-rings, and liners around every seam in the vacuum where air can get out. The actual bag compartment is ingeniously designed - not only is it lined with a rubber seal, but it has negative pressure when the vacuum is turned on so the shell is sucked and clamped down on the seal. It's 100% airtight, and the only place the air can go is through an initial large particulate filter, and then through the charcoal activated, electro statically charged filter. There are only a couple of truly sealed vacuum brands out there. Again though, it may not matter much to most people - especially if you don't have allergy problems. The Dyson still filters better than the Eureka crap sold at Wal-Mart. It's just not truly
HEPA compliant or hypoallergenic, which was very important to me since I have allergies and live in an old building. It totally depends on the building you live and whether you have pets, carpets, allergies, etc, but I think a fair number of people would be shocked at the respiratory difference a good sealed vacuum can make. Not only that, but it's a noticeable reduction in how often I have to dust my electronics, glass surfaces, and air conditioner filters.