HEPA stands for High-Efficiency Particulate Absorption. They’re used in a number of things from automobiles, planes, and—where you’ve probably seen them most—vacuum cleaners. What sets these filters apart from others? They have to pass US government standards that other air filters don’t. HEPA filters will eliminate up to 99.97% of particles at least .3 micrometers in size. Wow!
What Are They Made of & How Do They Work?
HEPA filters are made out of a network of fiberglass fibers. There are folded layers of these fibers in the filter, and as air passes through the filter, particles get stuck to the fibers. But it’s not just the layers of fibers that make HEPA so efficient. It’s the way they’re woven together. The fibers aren’t woven in a typical grid like most filters. Instead, they’re woven in an almost random maze that makes it extremely hard for any particles to get through.
Why Use a HEPA Filter?
HEPA filters are obviously good at catching the dust and other nasty particles that float into the air. If you’re an allergy sufferer at the severe level, even having a HEPA filter in your vacuum can help you breathe easier. Pollens, fungi, pet dander: they’re all easily captured by HEPA filters. Because my son’s allergies are so bad, I bought a vacuum that uses a HEPA filter, and while I was fairly certain that the HEPA thing was just going to be a fad, it’s really made a noticeable difference in the way he breathes.
HEPA Filters vs. MERV 13-16
The thing about HEPA, though, is that while it’s great in vacuums and planes and cars and even air purifiers, they aren’t made to fit things like your HVAC system, which ultimately has the biggest impact on the quality of air inside your house. If indoor air quality is as important to you as it is to me, the closest equivalent to a HEPA filter you can buy for your furnace will be rated 13-16 on the MERV scale. I personally use a MERV 13. It’s super effective at grabbing impurities, but be warned: it can take a toll on your HVAC system, and because it requires more energy to pull the air through it, you’ll see a spike in your electric bill. They’re also more costly, but for my dollar, they’re worth it.