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Choose the Right HEPA Air Purifier

choose the right HEPA air purifier

How To Choose the Right HEPA Air Purifier For You

The two major kinds of HEPA air purifiers are home/portable and built in systems for your HVAC.  The built-in systems are not covered here.

Portable units that can be moved from room to room are an ideal solution for older residences that have legacy heating systems. If you have an HVAC system, please consider adding a HEPA and possibly a UV inline unit to your systems. Ultraviolet light requires very strong, lengthy exposure to kill viruses. That’s the reason these inline units require trained expert installation and maintenance to kill.

A true HEPA only air purifier uses a paper, folded HEPA filter. There is no ozone or UV. If these options are present on your existing air purifier, it is recommended that you do not use them. Ozone in the amounts produced by home air purifiers is not enough to kill mold. Inhaled ozone may cause coughing, shortness of breath, and chest pain. Ozone may make asthma worse. The American Cancer Society warns against using UV. Note: this recommendation does not apply to inline UV units for a variety of reasons.

The amount of UV is similar – it won’t produce enough or the right kind of UV to kill much. Some home air purifiers have an electrostatic option.  There are concerns that electrostatic options add more pollution to your air than they remove. And then there’s the bad smell they produce. Electrostatic and UV air solutions are appropriate for inline HVAC systems, but not portable units.

So, a True HEPA Only Air Purifier contains only a folded paper HEPA filter. A charcoal or carbon filter added to HEPA is acceptable. Carbon/charcoal reduces VOCs (odors).

Why Can’t I Use A Plastic HEPA Filter And Wash It?

Dust is forced into the folds of the filter. When water is added, it washes some of the dust out, but some dust remains damp and lodged in the folds of the filter. Dust lives in mold. Water makes mold grow. So the next time you turn on your air purifier it will blow mold spores throughout your breathing zone.

The plastic HEPA filters should be replaced, not washed.

Does My Air Purifier Really Know The Air Quality Of My Room?

Sortof. Here’s how it really works. There is a company called Breezometer that licenses a lot of the “real time” sensor air quality updates based on EPA and other outdoor weather stations. Algorithms are used to modify the sensor output for your city and address.

Here’s a test for your device: Toast some bread and make sure you can smell the toast. Your reading should go up if your device is accurate. 

Another good way to to open a bottle of nail polish next to the device. It should immediately read elevated TVOCs or something similar.

Note: there are daily improvements in air quality sensors, so test yours to see if it is an algo or if it is really measuring your breathing zone air quality.

Things to Come

COVID-19 has turned the commercial HVAC industry on it’s head. Never before has ventilation become so important. Just coming on the market are systems that will control ventilation based upon the real time CO2 inside the area/room. There are positive with negative ion generation systems that produce both negative and positive ions at the same time, may promise to kill airborne viruses. More accurate sensors are debuting daily. These technologies are under peer review now. Come back soon to see updates

Read more about Why Particles Matter here.

Read more about Ozone Does Not Fix Mold here.

Read more about Allergens and Dust here.

See Consumer Reports air purifiers review.