How to Determine the Best Air Purifier to Buy

You might not see them, but you can definitely feel them. Indoor air contaminants, like pollen, dust mites, smoke and bacteria, can put your health at risk. For people without a whole-home ventilation system, portable air purifiers are an effective solution to minimize the effects of those irritating airborne particles.


Not sure how to choose? Here are the main things to consider when determining the best air purifier to buy for your home (and whether air purifiers are worth it).

Choosing the Right Type of Air Purifier

The first question to answer is this: what kind of air purification do you need?

Do you want to tackle dust, pollen, pet dander, chemicals, odours, bacteria, or a combination of the above? Are you looking to make a room more comfortable for someone with asthma or allergy symptoms?

Different types of air purifiers are designed for different forms of air pollution. The best air purifier to buy for your home will depend greatly on the kind of purification you expect.

  • Mechanical filters remove particulate matter from the air by forcing air through a barrier, like meshes or fibrous material. The effectiveness depends on the Minimum Efficiency Reporting Value (MERV) value of the filter. The higher the rating, the better it is at trapping particles.
  • HEPA is an advanced form of mechanical filtration that intercepts and traps particles as air passes through the fine mesh of the filter. It is highly effective (99.97%) at catching allergy-triggering particles like pollen, dust mites, and pet dander. HEPA does not filter out gas or odour molecules, like chemical vapours, cigarette smoke, or pet smells.
  • Activated carbon filters contain millions of tiny, absorbent pores that trap chemical fumes, odours and other particulate gases. They’re great for eliminating unwanted kitchen and bathroom odours and pet scents.
  • Ionic filtration produces an invisible cloud of charged ions that capture airborne particles through an effect like static electricity. It works on dust, pollen, and dander, and can also remove odours. However, ionic filters do produce a small amount of ozone, which can be harmful to people with respiratory problems.
  • Ultraviolet (UV) filtration uses invisible, ultraviolet light to kill bacteria and viruses. In hospitals and other medical facilities, HEPA filters are often combined with UV filtration to ensure the safest, most sterile environment for patients.

Many air purification systems combine more than one form of filtration to provide a wider range of coverage.

The 170 sq. ft. 02Clean Air Purifier uses a mechanical pre-filter, activated carbon filter, HEPA filter, and Ionizer function to filter out allergens like dust, dander and pollen as well as volatile organic compounds (VOCs). The 186 sq. ft. model includes HEPA filtration and a UV-C light and Photo-catalyst filter that eliminates bacteria and sterilizes the air.

Noise Level

Where in your home do you want to put the air purifier? If you plan to place it in a bedroom, you’ll want to check how much noise an air purifier makes before you buy it.

All mechanical air purification systems, including those using HEPA filters and activated carbon filters, use a fan. Typically, these fans are only about as loud as a small cooling fan.

The quietest air purifiers are those that only use ionic filtration, since ionizers do not use a fan.

Some air purifiers include specialized sound-dampening features. The 02Clean 170 sq. ft. air purifier uses patented Silencer Technology™ that keeps the noise to a whisper-quiet level (Noise dB ranges from 18dB to 47dB depending on the fan speed).


When people talk about ‘sizing’ an air purifier, they’re talking about its filtration capacity, not its physical size.

Portable air purifiers aren’t designed to be a one-size-fits-all solution. All air purifiers have a Clean Air Deliver Rate or CADR rating, which describes the amount of air the system can filter per minute. The higher the rating, the bigger the space the air purifier can handle.

To compare air purifier CADR ratings, check the square footage the air purifier is designed for. Small room air purifiers can function well with a lower CADR.

For example, the 02Clean model has a CADR of 110, meaning it can effectively keep the air clean in small to medium-size rooms up to 170 sq. ft. in size.

Maintenance and Operating Cost

There are two things to consider when comparing the costs of running an air purifier: filtration and efficiency.

HEPA filters and activated carbon filters must be replaced after approximately three months of use to perform effectively. Some air purifiers include a mechanical pre-filter that is washable and can prolong the life of disposable filters. Ionizers do not need replacing, but the tray that collects the particles must be washed.

As for electricity use, ENERGY STAR looks at CADR along with total energy consumption to gauge an air purifier’s energy efficiency. You can compare air purifier efficiency ratings under ENERGY STAR’s Room Air Cleaners category.

Is an Air Purifier Worth It?

Most people who buy air purifiers do so with a specific use in mind: alleviating allergy symptoms, creating a sterile environment for someone who’s ill, eliminating smells left by previous tenants, and so on.

As mentioned above, not all air purifiers are the same. Different filtration methods are designed to trap different kinds of particles. HEPA filters are great for tackling dust and pollen, for example, but they won’t eliminate odours (unless you pair them with activated carbon or ionic filtration.

When someone complains that their air purifier wasn’t ‘worth it’, it’s usually because they purchased the wrong type of air purifier, didn’t size it correctly, or failed to clean/replace the filter.

To get the most out of an air purifier, make sure to:

  1. Choose an air purifier that uses the best method(s) of filtration for your needs
  2. Size the air purifier correctly for the room

Clean or replace the filters as required by the operating manual