Introduction

The air we breathe is as much a part of home security as more obvious measures like security cameras and door locks. In this case however, we are not dealing with physical intruders; we are dealing with invisible ones. Allergens, smoke, carbon monoxide, radon, and volatile organic compounds are very real concerns depending on our location and living environment. Read on to determine whether you need an air purifier, the methods of air purification, as well as the best air purification products.



Editor's Recommendations

For the most secure home air quality, you need

If you are looking to combat smoke and second-hand smoke effects, then in addition to natural air ventilation, we recommend getting an air purifier with charcoal and ionizer capabilities. Check out our section on second-hand smoke. In certain cases, you may need to hire contractors to completely restore your smoke-damaged rooms with high-powered ozone generators.


Best Air Purifier Overall

Recommended Honeywell True HEPA Allergen Remover


Good For Medium to Large Rooms (470 sq. ft.)

CADR Ratings

Smoke300
Pollen300
Dust320
Pros
  • HEPA filter
  • Activated carbon (charcoal) filter
  • No ozone emissions
  • Mechanical filtration
  • 4 filtration levels
  • Timer for 2, 4, or 8 hours
Cons
  • Proprietary filter needs replacement every year
  • Can be loud on 2+ filtration level


Best Air Purifier for Smoke

Recommended Coway Mighty Air Purifier


Good For Smoke, Small to Medium Rooms (360 sq. ft.)

CADR Ratings

Smoke233
Pollen240
Dust246
Pros
  • HEPA filter
  • Activated carbon (charcoal) filter
  • Air ionizer
  • Auto mode adjusts based on sensors
  • Stylish form factor
Cons
  • Air ionizer may produce trace amounts of ozone
  • Proprietary filter needs replacement every year
  • Can be loud due to fan




Table of Contents



Tips and Tricks for Cleaner Air

Before we shell out any money for a dedicated air purifier, let's make sure we check the boxes for simple and effective methods we can do right now. These are immediately actionable and may be all you need to treat any pesky dust mites, mold spores, or pet dander among other pollutants.

  • Open your windows.
    Natural ventilation is one of the most effective and free ways to improve indoor air quality. Open edifices allow air to circulate in to and out from your home, diluting any potentially harmful pollutants that may have been generated. The flipside to this one is that, depending on where you live, your immediate outdoor environment may be just as bad or even worse - in which case, it's time to buy an indoor air purifier.

  • Buy plants.
    Air in our natural world is being continuously cleansed and processed by plants. It only makes sense to bring that goodness into the house. Even simple ones that require little effort to maintain can do wonders for air quality. We especially like snake plants.

  • Vacuum and dust often.
    Dust and other pollutants have to settle somewhere. The largest culprits are carpets and the surfaces of objects and furniture around the house. By vacuuming and dusting often, we can eliminate much of the particulates right from the areas they are most likely to get kicked up from.

  • Minimize smoke from smoking and fireplaces.
    The best treatment is prevention, and smoke damage is best treated by eliminating (or properly ventilating) smoking from the source. Insist on people only smoking outdoors, and keep fireplaces and chimneys swept and clean.

  • Maintain clean filters.
    The heating and cooling systems are primarily responsible for your indoor air circulation. Proper maintenance, which includes replacing filters when needed, can go a long way to improving your entire house's air quality.



Frequently Asked Questions (FAQs)


What is CADR?
CADR stands for Clean Air Delivery Rate. It is a standardized measure that tells us how much cubic feet of air per minute (CFM) is flowing with particles removed of a certain size distribution. In English, CADR tells us how much filtered clean air a product can deliver. CADR is usually measured across three factors: smoke, pollen, and dust (smallest to largest particle sizes). Generally, the higher the number the bigger the room a product can support.1

What is AHAM?
AHAM stands for Association of Home Appliance Manufacturers. The group develops and maintains standards (like CADR) for household products sold in the United States, which importantly are recognized by US government regulatory agencies like the EPA and DOE.2 Although there is potential for bias, having some industry standards are a good way to have baseline comparisons.


Reasons To Get An Air Purifier

We're data-driven people - so we love having concrete reasoning behind our decisions. We also realize there is a psychological benefit to thinking the air we are breathing is cleaner and fresher (placebo effect is a thing!). For those who like knowing some of the science behind air quality, the following are major reasons to get an air purifier and related air-cleansing products.


Allergens, Allergies, and Asthma

Definition An allergen is a type of antigen that produces an abnormally vigorous immune response (an allergy) in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Allergens can be found in a variety of sources, such as dust mite excretion, pollen, pet dander or even royal jelly.3

If you or someone in your home suffers from allergies, or even just happen to sneeze a little too often, then you should get an air purifier. Allergies are not just an inconvenience; they can trigger severe responses requiring hospitalization. Air purifiers will remove dust, pollen, pet dander, mold spores, and dust mite feces, and should be used in conjunction with thorough and consistent vacuum cleaning.

Definition Asthma is a condition in which your airways narrow and swell and produce extra mucus. This can make breathing difficult and trigger coughing, wheezing and shortness of breath. Exposure to various irritants and substances that trigger allergies (allergens) can trigger signs and symptoms of asthma.4

Like allergies in general, asthma can be triggered through a variety of allergens as well as pollutants like smoke (see the next section). Internal air quality for those with asthma is just as important as food and physical activity.

» Jump to product recommendations for Allergens, Allergies, and Asthma


Secondhand Smoke

Definition Secondhand smoke is smoke from burning tobacco products, such as cigarettes, cigars, or pipes. Secondhand smoke also is smoke that has been exhaled, or breathed out, by the person smoking. Tobacco smoke contains more than 7,000 chemicals, including hundreds that are toxic and about 70 that can cause cancer.5

The best and most obvious way to prevent secondhand smoke pollution is to treat it at the source - stop the actual act of smoking. If that is not an option however, then using HEPA filters, activated carbon, ionizers, and other mechanical air filters can reduce both the smell and detrimental health effects. Note that air purifiers are not a 100% effective solution.6 For dealing with damage from previous smokers or fires, look into ozone generator solutions (be careful with this one).

» Jump to product recommendations for Secondhand Smoke


Volatile Organic Compounds (VOCs)

Definition Volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids. Organic chemicals are widely used as ingredients in household products [like] Paints, varnishes;and wax... [and] many cleaning, disinfecting, cosmetic, degreasing and hobby products. 7

Due to the nature of their use, popular household products like paints, cleansers, and dry-cleaning all contribute to elevated indoor levels of VOCs. Symptoms range from flu-like symptoms to organ damage and even cancer. The best ways to mitigate these effects are limiting exposure and proper ventilation. Air purifiers that use activated carbon and charcoal can also reduce VOC presence.

» Jump to product recommendations for VOCs


Carbon Monoxide

Definition Carbon monoxide, or “CO,” is an odorless, colorless gas that can kill you. CO is found in fumes produced any time you burn fuel in cars or trucks, small engines, stoves, lanterns, grills, fireplaces, gas ranges, or furnaces. CO can build up indoors and poison people and animals who breathe it.8

If you experience unexplained headaches, dizziness, weakness, upset stomach, vomiting, chest pain, or general flu-like symptoms, immediately check your CO levels. For prevention, be smart about not burning things indoors, and have proper ventilation for your car garage and rooms connected to your heating system. CO poisoning can strike anyone anywhere, so monitoring is as essential as proper ventilation.

» Jump to product recommendations for Carbon Monoxide


Radon

Definition Radon is a gas that you cannot smell, taste or see. Radon forms naturally when uranium, thorium, or radium, radioactive metals, breaks down in rocks, soil and groundwater. People can be exposed to radon primarily from breathing radon in air that comes through cracks and gaps in buildings and homes. Because radon comes naturally from the earth, people are always exposed to it. When you breathe in radon, radioactive particles from radon gas can get trapped in your lungs. Over time, these radioactive particles increase the risk of lung cancer. Radon is the second leading cause of lung cancer after cigarette smoking.9

We'll just let the above definition speak for itself. Radon can have a serious long-term effect on your and your family's health if left untreated. Levels of radon can vary greatly by geography and season. If you have a basement or other home area close to the Earth or with poor ventilation, it is very highly encouraged to check for radon. The EPA recommends checking every 2 years and especially if you are buying or selling a house.

» Jump to product recommendations for Radon



Methods of Air Purification


Natural Ventilation

Definition Natural ventilation is the process of supplying air to and removing air from an indoor space without using mechanical systems. It refers to the flow of external air to an indoor space as a result of pressure differences arising from natural forces.10

The best form of air purification is by nature itself. Our windows and doorways to the outdoor world can drive fresh air into our homes through wind direction and temperature differences, in any latitude and longitude. Depending on the environment of where we live, though, using the immediate outdoor air may not be a good idea (and may sometimes be itself the impetus for getting an indoor air purifier; see air pollution). Cold outdoor weather with indoor heating also often prevents us from comfortably keeping windows open. Use your best judgment, but generally your first choice for air purification should always be natural ventilation wherever possible.


High-Efficiency Particulate Arrestance (HEPA) Filters

Definition The HEPA filter must satisfy certain standards of efficiency such as those set by the United States Department of Energy (DOE). To qualify as HEPA by US government standards, an air filter must remove (from the air that passes through) 99.97% of particles that have a size of 0.3 µm.11

HEPA filters trap small pollutants and particulates in air passing through the filter using a mat of fibres. In particular, allergens like dust and pollen are very effectively captured, making HEPA a necessary requirement for any solutions dealing with allergies and asthma. Because of the popularity of HEPA, some products may claim to be "HEPA-type" or "HEPA-like", which do not meet the DOE requirements. Many vacuum cleaners now also boast HEPA filters (great for keeping the carpets allergen-free).


Activated Carbon & Charcoal Purifiers

Definition Activated carbon is a form of carbon processed to have small, low-volume pores that increase the surface area available for adsorption or chemical reactions. Filters with activated carbon are usually used in compressed air and gas purification to remove oil vapors, odor, and other hydrocarbons from the air.12

Aside from HEPA, activated carbon is the most common and effective type of air purification. Activated carbon uses pores to absorb smoke particulates, odors, and VOCs, something HEPA cannot do - it's not a coincidence that we see the HEPA + Activated Carbon combination in many modern air purifiers.


Air Ionizers

Definition An air ioniser is a device that uses high voltage to ionise (electrically charge) air molecules. Airborne particles are attracted to the electrode in an effect similar to static electricity. Air ionisers have been used to eliminate the occurrence of air-borne bacterial infections... [as well as] inactivate viruses including influenza.13

Air ionizers have recently become popular in air purifiers due to epidemics like the SARS virus. Our greatest concern however with air ionization (and a related form called electrostatic precipitation) is that they produce trace amounts of ozone - usually within industrial safety standards, but variation in manufacturing and individual reactions to ozone means we all need to be cautious and do sufficient testing in order to add this purification method to our arsenal.


Ultraviolet

Definition Ultraviolet germicidal irradiation (UVGI) is a disinfection method that uses short-wavelength ultraviolet (UV-C) light to kill or inactivate microorganisms. UVGI can be used to disinfect air with prolonged exposure.14

Ultraviolet irradiation requires time for sufficient exposure to kill germs like bacteria, viruses, and molds. For this reason typical air purification systems with moving air are not effective with UVGI (don't be sold by the hype!). Ultraviolet is useful when used in areas that are prone to natural moisture, as they can prevent bacteria from accumulating.



Product Reviews


Overall


Recommended Honeywell True HEPA Allergen Remover


Good For Medium to Large Rooms (470 sq. ft.)

CADR Ratings

Smoke300
Pollen300
Dust320

The HPA300 is one of Honeywell's flagship air purifier, good for medium to large size rooms with the full arsenal of purification methods - including HEPA, activated carbon, and mechanical filtration (forceful air intake). The HEPA and activated carbon together will combat most allergies and odors including pet dander. Owners really like having the 4 filtration levels - Germ, General Clean, Allergen, and TURBO - with the caveat that General Clean and later levels can be white noise-like loud. Although it doesn't have an automatic sensor like the Coway, having a timer setting is nice for a set-and-forget clean whenever you need it!

Pros
  • HEPA filter
  • Activated carbon (charcoal) filter
  • No ozone emissions
  • Mechanical filtration
  • 4 filtration levels
  • Timer for 2, 4, or 8 hours
Cons
  • Proprietary filter needs replacement every year
  • Can be loud on 2+ filtration level



GermGuardian AC4825


Good For Small Rooms (160 sq. ft.)

CADR Ratings

Overall100+

The GermGaurdian air purifiers are consistently Amazon top 10 best sellers in both HEPA Air Purifiers and Charcoal Air Purifiers categories, as well as in Overall Home Air Purifiers. The GermGuardian models use a multi-layered approach to purification: activated charcoal filter, then HEPA, and combined with ultraviolet-activated Titanium Dioxide (more info on this method, may not be very effective; see our note on UV-C above). The AC4825 is 22" and perfect for smaller-sized rooms; a great entry point for those that want to try an air purifier but don't want to shell out for a more expansive one.

Pros
  • HEPA filter
  • Activated carbon (charcoal) filter
  • Ultraviolet light (UV-C) with Titanium Dioxide
  • No ozone emissions
Cons
  • Proprietary filter needs replacement every 6-9 months
  • Can be loud due to fan


Want to go bigger? GermGuardian offers an older brother 28" model called the GermGuardian AC5250 for those with slightly larger rooms (CADR 125+).


Want to go smaller? GermGuardian offers a nice-looking little brother 11" model called the GermGuardian AC4100, perfect for those with smaller spaces, like a bedroom or studio apartment. The features are all the same.

GermGuardian AC4100





Recommended Coway Mighty Air Purifier


Good For Small to Medium Rooms (360 sq. ft.)

CADR Ratings

Smoke233
Pollen240
Dust246

For a stronger punch, consider the Coway Mighty Air. The main difference between this air purifier and our recommended purifier (GermGuardian) is the addition of an ionizer - we talked about the inherent risks of using an ionizer (they produce ozone), so make sure you have a good reason to get a stronger air purifier. The other big advantage of the Coway is the automatic mode: sensors in the machine monitor air quality levels and adjust the fan level based on what it sees. Great as a set-and-forget.

Pros
  • HEPA filter
  • Activated carbon (charcoal) filter
  • Air ionizer
  • Auto (and Eco) modes adjust based on sensors
  • Timer for 1, 4, and 8 hours
  • Stylish form factor
Cons
  • Air ionizer may produce trace amounts of ozone
  • Proprietary filter needs replacement every year
  • Can be loud due to fan



Dyson Pure Cool Link


Good For Medium Rooms, Air Circulation

CADR Ratings

OverallUnknown

Dyson is known for their aesthetics, and the Pure Cool Link lives up to the style. The iconic blade-less oval offers safe air circulation (it doubles as a fan) in conjunction with HEPA filtration and activated charcoal for the standard 1-2 punch for allergens and odor. Since there is no CADR rating, the actual air quality standards are a bit of an unknown - though Dyson is an established consumer product brand. We'll update as we learn more. Besides having a sleek design and strong air circulation, the Pure Cool Link has physical sensors for air quality, a mobile app for remote monitoring (great for families), and a night-time mode for quieter functioning when the kids are sleeping.

Pros
  • HEPA filter
  • Activated carbon (charcoal) filter
  • Physical air quality sensors
  • Night-time mode
  • Mobile app for monitoring
  • Stylish form factor
Cons
  • Proprietary filter needs replacement 9-12 months
  • No CADR rating
  • Can be loud due to fan



Holmes Egg Air Purifier


Good For Small Rooms (120 sq. ft.)

CADR Ratings

OverallUnknown

The Holmes HAP600-U Egg Air Purifier is a fun and portable air purifier for a small space. It uses a HEPA-type filter (not to be confused with true HEPA) that never needs replacing - which is great for picking up dust, but cannot catch smaller allergens in many cases. Pick this one up if you want an inexpensive and stylish dust-catcher.

Pros
  • Permanent filter does not need replacing
  • Fun form factor
Cons
  • Not a true HEPA filter
  • No CADR rating
  • Can be loud due to fan



Sharp KC-850U Plasmacluster


Good For Small to Medium Rooms (250 sq. ft.), Humidifier

CADR Ratings

Smoke164
Pollen174
Dust164

The Sharp Plasmacluster is all business and performs like it. CADR ratings of 150+ across the board make this a great solution for the no-nonsense homeowner to take care of allergens and odor. We like the Plasmacluster because it also acts as a humidifier, with built-in sensors to monitor humidity levels (as well as dust levels). The downside is that there is no timer though the "Auto" and "Pollen" modes will work just fine. Users have reported the need to keep this filter away from a wall, so make sure you take that into account.

Pros
  • HEPA filter
  • Activated carbon (charcoal) filter
  • Humidifier built-in
  • Two automatic modes, "Auto" and "Pollen"
  • Sensors for humidity levels and dust levels
Cons
  • Proprietary filters need replacing every 5 years (2 for humidifier)
  • Can be loud due to fan
  • No timer



For Carbon Monoxide

Detection (and subsequent professional work to fix the root cause) is the best way to combat potential carbon monoxide poisoning. The recommendation is to have a carbon monoxide detector in every floor of the house, as well as any further enclosed area with poorer ventilation.


Recommended Kidde Nighthawk


The Kidde brand is the best in the fire and smoke detection market. This product, the Nighthawk, is the highest rated no-fuss carbon monoxide detector and alarm from Amazon. We like that it is both plug-in and battery for continuous use, something most other similar products do not have.



Kidde Battery-Operated


The Kidde Battery-Operated detector and alarm is similar to the Nighthawk but is smaller and only battery-operated, making it more portable. Functionality is nearly identical.



Recommended Leeo Smart Alert Alarm


Want to go cutting edge in an easy and inexpensive way? Leeo is a startup developing safety and security technology. Their first product is a monitoring and alerting device - note that the Leeo Smart Alert does not actually itself monitor smoke and carbon monoxide levels, but rather listens for alarms usually coming from smoke and carbon monoxide detectors. Once detected, it alerts your iOS or Android phone (via connection with your home wifi network), then escalates to calling you if necessary, and finally to an alert to your emergency contacts if all else fails. If you have an old-school non-wifi alert like the above Kidde products, then the Leeo is the perfect upgrade. It is smart home-compatible via IFTTT and has adjustable nightlight colors.

Pros
  • Complements existing non-connected devices
  • Remote alerting and escalation
  • Smart home compatible via IFTTT
  • Doubles as a nightlight
Cons
  • Requires a wall outlet
  • No actual detectors itself
  • Relies on consistent alarm sounds



For Radon

Like carbon monoxide, detection and professional work is the best route for radon poisoning.


Recommended National Radon Program Services Test Kit


The EPA recommends the National Radon Program Services discounted test kit offered through Kansas State University. Both short-term ($15) and long-term ($25) kits are offered with free analysis, with the latter being much more accurate.




First Alert RD1


If for some reason you cannot use the National Radon Program Service, the First Alert RD1 is a great alternative. It is EPA-listed, inexpensive, and easy to use, with no hidden fees for analysis.



Conclusion

We take the "invisible" security of home air quality just as seriously as physical security. For overall air quality, natural ventilation can't be beat, and an additional general-purpose air purifier can help a lot. Carbon monoxide and radon detection are also necessities, especially if you are considering buying or selling a home. Breathe deep and stay lazy, friends!

Thoughts or questions? Let us hear them in the comments below!





References