Air purifiers with activated carbon plus additional sorbent materials targeted to formaldehyde are the best option for removing formaldehyde from your indoor air. You generally need a lot of carbon (and other sorbent material) to make a significant dent in the problem.
This list of air purifiers looks at those with the highest amount of sorbent material – starting at 30 lbs and going down to 12 lbs.
Activated carbon is the base material used to combat volatile organic compounds VOCs, but in order to deal with formaldehyde and acetaldehyde you want to look for options that include Zeolite, Potassium Iodide, or Potassium Permanganate.
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Which Technologies Are Best for Formaldehyde Removal
Air filters with activated charcoal will remove most volatile organic compounds (VOCs) and odors. Carbon is especially effective against organic compounds like benzene as well as chemical gasses like chlorine (CARB, HSW). Activated carbon does adsorb (bind to) formaldehyde in the air (source) but it’s not the best solution on its own.
The adsorptive performance of activated carbon can be enhanced by surface modification which some air filters might be utilizing.
Zeolite and Potassium Iodide
Zeolite can adsorb formaldehyde (source).
Austin Air with Zeolite and Potassium Iodide showed much better reduction in formaldehyde, acetaldehyde and dichloromethane in an independent test compared to carbon and other filter types. In that same test, activated carbon alone was not effective against these three light compounds.
Alumina and Potassium Permanganate
Potassium Permanganate-based filters are commonly used to target strong odors, smoke, and some VOCs. When formaldehyde molecules come into contact with the Potassium Permanganate on the activated carbon, they undergo a chemical reaction that converts formaldehyde into less harmful byproducts, such as formic acid. Alumina, like activated carbon, is also used for adsorption purposes, and when impregnated with Potassium Permanganate, it gains additional capabilities for oxidation. The combination creates a chemical filter media that can effectively adsorb and oxidize formaldehyde molecules.
Companies claim that Potassium Permanganate can help increase the filters ability to break down formaldehyde. It will also remove most mercaptans (the ‘smell’ of natural gas) and other odorous gases related to gas, such as hydrogen sulfide. (CARB)
Lower your Humidity and Temperature
Activated carbon in an air purifier works best at removing formaldehyde if your humidity is low inside your house and when the temperature is not too high. (source)
What to Look for in a Good Air Purifier:
- High Amount of Sorbent Material – If you want activated carbon to bind chemicals, the number of pounds of carbon is key. Zeolite, Potassium Iodide, and Potassium Permanganate extend the ability to remove formaldehyde.
- Ideally “True HEPA” – which filters 99.97% of particles done to 0.3 microns. While this isn’t related to formaldehyde removal, HEPA air filters can theoretically remove at least 99.97% of dust, dust mites, pollen, pet dander, mold, particulates from smoke, bacteria, some viruses, and any airborne particles with a size of 0.3 microns or larger (EPA, PudMed).
- Around 5 ACH (air changes per hour) – The CFM (cubic feet per minute) is how much air the air purifier can move through the filters. This will tell us how many air changes we can get in a space. Air change 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. You want at least 1 ACH, and up to 5 ACH for sensitive folks or highly polluted areas.
- 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).
Note on Air Changes Per Hour (ACH):
How Do You Calculate the ACH From a Unit’s Specs – You need the CFM to calculate ACH. CFM stands for Cubic Feet Per Minute, this is the capacity of the unit to move air – how much air it moves through the machine. I have two calculators here to properly size these units based on CFM.
Top Brands of Air Purifiers for Formaldehyde Removal
This is my top pick. It has the best value for comprehensive filtration: True HEPA, 15 lbs of Carbon, plus Potassium Iodide and Zeolite for the best chemical coverage of formaldehyde.
Healthmate Plus $885
- 15 lbs of Activated Carbon impregnated with Potassium Iodide and Zeolite
- 250 CFM
- True HEPA (Removes 99.97% of all particles larger than 0.3 microns and 99% of all particles larger than 0.1 microns)
- dB 50-66 3-5ft
- EST early 90s
This is one of the most well-trusted brands in air purifiers. The high level of sorbent material eliminates a wide range of gases, chemicals, VOC’s and formaldehyde (the Potassium Iodide + Zeolite works best on formaldehyde). The unit itself is all metal (apart from the wheels).
Coverage: In 400 sq ft you get 5 air changes per hour (running on high). In 2000 sq ft you get 1 air change per hour. Great for high turnover in small and medium-sized rooms with still a 1 ACH in large rooms.
Colors: Black, Dark Blue, White, Tan. The Baby’s Breathe Model comes in Pink and Baby Blue (but does not have pounds of carbon).
Filter replacement: HEPA/carbon pre-filter 3-5 years $360. A more realistic life expectancy for the filters is 2 to 4 years, with the carbon likely becoming saturated before the HEPA filter. Still, the filters are protected by a 5-year pro-rated guarantee.
Cons: Not the quietest air purifier on the list. There is no concrete way to tell when the filters are actually saturated and should be changed other than when you start to smell the carbon offgassing. Both carbon and HEPA filters are attached so if one is maxed out you need to replace both.
Less Expensive Option: The Healthmate Jr Plus for $465 has 6.5 lbs of granular carbon/zeolite with Potassium Iodide. It has 125 CFM.
While this has less carbon than some of the other models, it has Alumina impregnated with Potassium Permanganate so we would expect it to remove more formaldehyde than carbon-only filters.
IQAir Multigas $1299
- 12 lbs granular activated carbon & Alumina impregnated with Potassium Permanganate
- CFM 300
- True HEPA
- dB 35-69 (at 3 ft)
- EST 1963
This might be one of the best-known brand names in air purifiers. Lots of people swear by it even though the amount of carbon is lower than the others; the additives make it efficient.
The addition of Alumina impregnated with Potassium Permanganate to the Carbon adds protection against chemical contaminants such as formaldehyde, hydrogen sulfide, sulfur dioxide, and nitric oxide.
Coverage: In 500 sq ft you get 5 air changes per hour (running on high). In 2500 sq ft you get 1 air change per hour. Good for small, medium and large rooms.
Colors: MultiGas comes in white with blue stripe, HealthPro (pictured above) in white or wood look.
Filter replacement: Multigas cartilage 2 years $400; Post Filter 2.5 years $129; HEPA about a year (on 10 hours a day on speed 3) $109; optional Filter Pads $79. Color-coded lights indicate when a filter change is needed.
Cons: It’s large and not particularly aesthetic. The filter costs are somewhat high.
Their HealthPro Plus, $899, comes with 5 lbs of carbon, is 40 to 300 CFM and that gets you 2 air changes/hr in 1125 sq. ft, dB 25 to 59
This has a higher amount of carbon + Potassium Iodide than the first two, and a high CFM for large areas, but no True HEPA filter. If formaldehyde removal is a higher priority than True HEPA, this is the one to go with.
Airpura C600 DLX $950
- 26 lbs of Coconut Shell Carbon with Potassium Iodide
- 440 CFM
- No True HEPA filter, the HEPA filter captures 1 micron and greater
- dB 28.1 – 62.3 @6ft.
- EST 2004
This little unit has a very high CFM (second highest on the list) so it’s good for large spaces. The C600 DLX is for chemicals and gas abatement. It contains 26 lbs of an impregnated Carbon Filter with Potassium Iodide for maximum formaldehyde abatement.
It removes more than 4,000 chemicals, including formaldehyde, VOCs from new construction, ammonia, benzene, toluene, radon, glues, pesticides, methylene chloride, mold mycotoxins, perchloroethylene, hydrogen sulfide, mercury vapors, hydrogen bromide, sulfur dioxide, chlorine, and more. It’s good for new homes and it’s good for homes/workplaces that are in proximity to manufacturers that release chemicals from their manufacturing processes.
It has all metal housing and can work well for chemically sensitive folks.
Coverage: In 700 sq ft you get 5 air changes per hour (running on high). In 2500 sq ft you get 1 air change per hour. Good for small, medium, and large rooms.
Colors: Black, Cream, White.
Filter replacement: Carbon filter 2-3 years $350; Post filter 1 year $100; Pre-filter 6-12 months $40; filter 1-2 years $60
Cons: No True HEPA filter. It will capture airborne particulates 1 micron and greater, but does not have the ability to capture sub-micron particles. No filter change indicators. Replacing the filters requires some work – the C600 needs to be turned upside down and the unit weighs 49 lbs.
This is the lowest-cost option with the highest level of carbon (alongside Allerair) for medium-sized rooms. However, we don’t know what is in the carbon mixes.
Amaircare 3000 $759
- Up to 30 lbs of carbon, depending on the option you choose
- 265 CFM
- True HEPA
- dB 43 to 61 @ 6 ft
- EST 1994, Made in Canada
This all-metal construction is well-liked by those with chemical sensitivities. It’s the lowest-cost option with a very high level of carbon.
They also have the following filter options for a wider range of filtration: Formaldesorb option for formaldehyde, and Multisorb for a mix of VOCs. They don’t say what is in these sorbent mixes.
Coverage: In 400 sq ft you get 5 air changes per hour (running on high). In 2000 sq ft you get 1 air change per hour. Good for small and medium-sized rooms, though you still get 1 ACH in large rooms.
Colors: Black or White.
Filter replacement: Pre-filters + VOC media/year (12 lbs) $119; HEPA Filter 2-5 years $200. The HEPA is rated at 2-5 years when the prefilter is maintained. Touch pad control panel indicates when each filter needs to be replaced.
Cons: You need a screwdriver to change the filter.
Alongside Amaircare, this has the highest amount of carbon mix with a very high CFM (the highest on the list) to move air through so much carbon. However, it’s a carbon-only mix.
AirMedic Pro 5 Ultra $1399
- 28-30 lbs carbon
- Super HEPA or True HEPA
- 560 CFM (and you can upgrade to 730 CFM)
- dB 39-62 dB @ 6 feet
- EST 1994
AllerAir is a very hefty home air filter with the highest amount of carbon on the market (alongside Amaircare).
The Vocarb sorbent mix is the best for higher pollution levels, VOCs, chemicals (formaldehyde etc.), fumes, and odors. The Vocarb mix is a mix of two types of carbon. (They have over 40 blends of carbon for specific pollutants).
This is also the highest CFM option on the list so the fan can pull through so much carbon.
Coverage: In 900 sq ft you get 5 air changes per hour running on high. In 2700 sq ft you get 1 air change per hour. Good for small, medium and large rooms.
Colors: It comes in White, Black and Tan. Special order: Pewter, Copper
Filter replacement costs: Carbon Filter 2-5 years $172; Super HEPA 2 years $131; Pre-filter 3 months $132
Cons: No change filter indicator. You need to undo screws at the bottom to change the main filters. We don’t know what’s in the carbon mixes so we can’t fully evaluate its effectiveness.
AirMedic Pro 5 HD MCS is made for people with multiple chemical sensitivities (MCS) – They burn in the motor by running and offgassing it for 6-8 hours. It has 24 lbs carbon and is dB 35-60 @1ft.
Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.