Updated Fall 2021
This post lists and compares the 7 best air purifiers to reduce VOCs (offgassing from new building materials).
I also focus on which units have the least amount of offgassing and are best for the chemically sensitive.
I have a separate post for air purifiers that work best for mold, however the True HEPA filter in these units does help in capturing mold spores.
This post contains affiliate links. Upon purchase, I earn a small commission through affiliate links at no extra cost to you.
What to Look for in a good Air Purifier:
- Good Amount of Tolerable Sorbent Material – How many lbs, type of material, tolerability of material, does it have potassium permanganate (which may be harder to tolerate but provides better absorption of many VOCs), do they have test kits to try the material.
- Ideally “True HEPA” – 99.97% of particles done to 0.3 microns.
- Around 5 ACH – CFM to tell you the air exchanges/hour, you want a least 1 ACH, ideally 5.
- Minimal Offgassing – Plastic or glue in the unit? Glue in the filters? Motors “burned in” or encased/sealed?
- Other Comparisons – How loud they are (dB), the cost of replacing filters, and year established (so you can feel certain they will be around to replace filters and parts).
Air Exchange Per Hour (ACH)
What are Air Exchanges Per Hour (ACH) – Air exchange per hour is how many times you are “replacing” the air in the room per hour, this is a key area of comparison with air purifiers. ASHRAE (The American Society of Heating, Refrigerating and Air-Conditioning Engineers) recommends a minimum of 4 ACH for patient rooms in hospitals, 5 for intensive care units and 25 for operating rooms.
How Many ACH Do We Need – For the purposes of those extremely sensitive to mould and VOCs, we want about 5-10 air exchanges per hour. To maximise how much air in the room the air purifier can process, put it in a central location.
How Do You Calculate the ACH From a Unit’s Specs – You always want to find the CFM of the unit. The CFM is the capacity of the unit to move air – how much air it moves through the machine. CFM stands for Cubic Feet Per Minute. You need the CFM to calculate ACH. I have two calculators here to properly size these units.
If you are interested in PCO technology that is more geared towards filtering mold, see my article on air purifiers that use that technology. This article is about the classic types.
Top Brands of Air Purifiers for MCS and Offgassing
AirMedic Pro 5 Ultra
$1049 * 28-30 lbs carbon * “Super HEPA” * 400 CFM * dB 50-75 @1ft * EST 1994
Filter replacement: Carbon Filter 2-5 years $172; Super HEPA 2 years $131;
Pre-filter 3 months $132
Some of the most extremely sensitive folks prefer this brand but not all have tolerated it. All-metal. Filters don’t offgas. No glue on the HEPA like true HEPA has. Option to have true HEPA which has glue.
AirMedic Pro 5 HD MCS is made for MCS – The burn-in motor by running and offgassing it for 6-8 hours. You can choose the carbon blend from an option of 7 blends in a test kit. It has 24lbs carbon and is dB 35-60 @1ft.
$885 * 250 CFM * 15 lbs of Activated Carbon Impregnated with Potassium Iodide and Zeolite * True HEPA * dB 50-66 3-5ft (they are not sure) * EST early 90s
Filter replacement: HEPA/carbon prefilter 3-5 years (5-year warranty filter warranty) $360
There are different filter options with different types of carbon/absorptive material. Again, reactions are often attributed to Potassium permanganate. You can test out their different filter options.
Steel units, plastic on the wheels, not plastic inside.
Some with extreme MCS have picked up offgassing, but many with MCS prefer this brand.
$699 * CFM 250 * dB 50 on high @6 ft
EnviroKlenz is a slightly different technology than the others here. I have been using this unit and been happy with it.
Like the others, this unit has a HEPA filter, but instead of charcoal/PP/zeolite it uses minerals including magnesium oxide, zinc oxide, and titanium dioxide to neutralize VOCs, chemical odors, and smoke.
The EnviroKlenz according to the literature, destroys most pollutants. Contrary to odor masking methods, the nanocrystalline materials contact, adsorb and then neutralize the odor-causing substances.
It is effective against aldehydes and pollutants and particularly effective against different kinds of smoke and pesticides. Activated carbon does not help that much with formaldehyde and smoke can be difficult to filter as well. My preference for this unit comes from its ability to deal with formaldehyde and smoke.
EnviroKlenz materials will chemically dismantle many VOCs. Hydrocarbons will be absorbed but not chemically modified.
The company has a number of patents and it has been tested you can see that info here (you can search and read patents here), and for a summary of research articles and references on this technology the company also provides a technical report.
Filter replacement costs: Mineral cartridge 4-5 months 100$, HEPA every 2-3 years $150. Rated the same as true HEPA.
This air purifier has been in production for 8 years.
4. E.L. Foust
400 Series Air Purifier
$775 * CFM 380 * 60% Coconut shell carbon / 40% potassium permanganate (Standard Mix) 8 lbs * not true HEPA, 99.97 * dB 22-24 @3ft * EST 1974
Filter replacement: HEPA which can last up to 2-3 years $112. Pre-filter 2-3 months $13. Carbon media tray 6-9 months, up to a year $75
They have a sealed motor – bearings are sealed in. They run the motors outside for 2-3 days first to offgas them.
Metal construction uses no adhesives, have HEPA filters without any glue. These are made for the chemically sensitive and some of the most extremely sensitive like this brand.
They sell filter sample kits so that you can check out the different materials used. Generally, for the extremely sensitive, PP is difficult to tolerate. The most sensitive should start with their pure Bituminous coal filters.
Having a sealed motor will be key for the most sensitive. The downside is this one has a lot less carbon than the other models.
Purchase only from their website.
$1299 * CFM 300 * 12 lbs granular activated carbon & impregnated alumina (Potassium Permanganate) * True HEPA * dB 35-69 – (the company will not state how many feet this test was done at). * EST 1963
Their HealthPro is (40 to 300 CFM) (2 air changes/hr in 1125 sq. ft), dB 25 to 59
Filter replacement: Multigas cartilage 2 years $400; Post Filter 2.5 year $129; HEPA about a year (on 10 hours a day on speed 3) $109; optional Filter Pads $79
This might be one of the best-known brand names in air purifiers. Some people with MCS swear by it. But, the most severely sensitive do not always tolerate it.
The unit is made of plastic and the offgassing of the unit itself might be an issue. The potassium insert can be hard to tolerate for many (which is not a unique issue to this brand). Some people have sent back filters that smelt especially sweet or strong and received ones that were more tolerable.
Nevertheless, this is a favorite and well-trusted brand for many with MCS who want a robust top of the line air purifier.
$719 * 225 CFM (in 1688 sq ft 1 ACH) * Claims no offgassing * Depending on the option you choose it contains up to 30 lbs of carbon * True HEPA * dB 43 to 61 @ 6 ft * EST 1994 * Made in Canada
Filter replacement: Prefilters + VOC media/year (12 lbs) $119; HEPA Filter 2-5 years $200
Made of metal, no plastic or foam. The HEPA is rated at 2-5 years when the prefilter is maintained. One person with moderate MCS said the HEPA filters smelled like chemicals. He requested a new one which was better.
$900 * 440 CFM (2 air exchanges an hour 2000 sq. ft. with) * 26 lb Coconut Shell Carbon * dB 28.1 – 62.3 @6ft. * EST 2004
Filter replacement: Carbon filter 2-3 years $350; Post filter 1 year $100; Pre-filter 6-12 months $40; HEPA (not true HEPA) 1-2 years $60
Claim all-metal housing, ensures no plastic vapors are emitted.
It didn’t work for some people with MCS although some do well with it.
They sell these at Walmart.
Corinne Segura is a Building Biologist Practitioner with 7 years of experience helping others create healthy homes.
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