OK, before I talk about HEPA, I have to confess that us Warners LOVE our Miele vacuums. Most of us, and a number of our sales associates, are believers – actively seeking converts, so please excuse the enthusiasm.

I never understood the whole $700-for-a-vacuum thing until I used my cousin’s Miele to vacuum her entire first floor without waking her twin babies. That thing is so quiet, you would think it’s broken if it wasn’t so darn powerful. Pennies, paperclips, short animal hair – just once over and it disappeared.

When I told my sister about this, she agreed but said it was really the HEPA filter that made the Miele great. And I nodded along, but admittedly, I didn’t haven’t a clue what HEPA meant.

So I asked our Miele rep on the phone the other day, “What is HEPA and why does my sister care about it so much?”

Miele Vacuums + HEPA

His response was pretty helpful (and humorous).

“First understand that I could put a HEPA filter on your shoulder and call you a HEPA person and it doesn’t mean anything,” he said. I had to laugh, but as I listened on, it made more sense.  Miele vacuums are the only truly HEPA-certified vacuums on the market.

HEPA, or high efficiency particulate arrest, was invented by the Army Corps of Engineers to combat chemical toxins. The U.S. HEPA standard requires 99.75% of all particles 0.3 microns in diameter be filtered. That’s teeny tiny — about 1/200th of a strand of hair.

“Well, how many of these things are actually in my house?” I asked.

The average home contains about 250,000 particles per square foot (1 million in an industrial warehouse setting like mine). And when we breathe, “gross stuff” (i.e. pet dander, pollen and even dust mite fecal matter) enters our blood stream through our lungs.

Does this matter to you? Maybe. If you have allergies or respiratory health problems, it definitely should. There’s no question using a HEPA filter to trap particles improves your breathing. And if you live in a newer construction home, HEPA becomes important because the quality of the insulation and windows mean that “fresh air” doesn’t really get in and current air simply recycles itself.

And if you’re already using a “HEPA” vacuum, you might want to double-check it.

“Some vacuum cleaners spit out particles through their exhaust system instead of trapping them inside the vacuum,” he said. “Just about every brand has a HEPA vacuum. But those units aren’t necessarily making use of the HEPA. It has to be able to filter all those particles to 99.7%.”

HEPA filters are tested to 10 cubic feet of airflow per minute, he said. Even low-quality vacuums can move about 60 cubic feet per minute. So what happens when you put a HEPA designed for 10 cubic feet per minute on a vacuum that moves 60 cubic feet of air per minute? The air is going to go around the filter and basically recirculate the debris.

“There are many vacuums created with leaks to help the air escape,” he said. “It’s like putting your thumb on a hose.” And that was it. The thought of dust mites and their “gross stuff” shooting out of a vacuum was enough to make me really, REALLY care about HEPA.

Miele vacuum cleaners generate over 100 cubic feet of airflow per minute and the HEPA filter is tested on the vacuum to ensure it’s truly sealed and can contain the debris. For more info, read our vacuum cleaner buying guide.

These vacuums are certainly an investment – they last upwards of 20 years – or a really, really generous gift (we ship for free!).  An all-surface vacuum with True HEPA filtration,  such as the S7 series uprights,  start at $649. Vacuum cleaners for smooth surfaces and low-pile carpeting start at about $300, after adding a HEPA filter.