Understanding Air Purifier Specifications and Ratings

Have you ever noticed those big, complicated numbers and abbreviations on the boxes of air purifiers?

While they might look confusing at first, those specifications and ratings actually provide important information about how well an air purifier can clean the air in your home. Think of them as clues that can help you choose the best air purifier for your needs!

In this article, we’ll break down some of the most common air purifier specifications in simple terms. By the end, you’ll be a specification super-reader, ready to pick the perfect purifier!

CADR Ratings: Measuring Cleaning Power

One of the biggest numbers you’ll see is the CADR rating. CADR stands for “Clean Air Delivery Rate.” It tells you how many square feet of space an air purifier can effectively clean in a specific period of time.

The CADR rating has three numbers that measure how well the purifier captures:

Dust particles
Pollen particles

Higher CADR numbers mean the air purifier can clean more air in a larger room. For example, an air purifier with a Dust CADR of 300 can cleanse the air in a 300 square foot room very quickly.

When shopping, match the air purifier’s CADR to the square footage of the room you want to use it in. Bigger rooms require higher CADR ratings for the best results.

Air Changes per Hour (ACH): Freshness Factor

Another number to look out for is ACH, which stands for “Air Changes per Hour.” This tells you how many times the air purifier can completely refresh the air in a room each hour.

For example, an ACH of 4 means the purifier processes and cleans all the air in that room 4 times every single hour! The higher the ACH, the more times “fresh” clean air will circulate through that space.

ACH matters because adding that much purified air quickly helps reduce airborne allergens, odors, and other pollutants more efficiently. For best results, look for purifiers with an ACH of at least 4 or higher.

Air Purifier Filter Types

At the heart of every air purifier is a filter system that captures different pollutants from the air passing through it. There are several common filter types:

HEPA Filters

HEPA (High-Efficiency Particulate Air) filters are super dense materials that can trap extremely tiny particles like dust mites, pet dander, mold spores, and smoke particles.

By EPA standards, a True HEPA filter must remove at least 99.97% of particles 0.3 microns or larger from the air that passes through.

Carbon/Activated Charcoal Filters

These filters use special treated carbon materials to absorb and trap gaseous pollutants and odors like smoke, cooking smells, VOCs (volatile organic compounds), and more.

UV Light Filters

Ultraviolet (UV) light filters use special UV lamp bulbs to help eliminate germs, viruses, bacteria, and microbes as air circulates through the purifier.


Many purifiers have less dense pre-filter layers that capture larger dust, hair, and other debris before the air reaches the main filter. This extends the life of the expensive HEPA or carbon filters.

Different combinations of these filters allow purifiers to target specific pollutants. HEPA filters are best for allergens, carbon for odors, and UV for germs. Many use multiple filter types together for complete air cleaning.

Energy Star and CARB Certifications

On air purifier boxes, you might also notice special logos and certifications that show the product meets important clean air standards.

Energy Star Certified

If an air purifier has the blue Energy Star logo, it means the product has been tested to prove it runs efficiently while still cleaning the air thoroughly. Energy Star certified purifiers can save you money on electricity costs.

CARB Compliant

CARB stands for the California Air Resources Board. This certification confirms the air purifier releases zero or very low levels of ozone emissions during operation. Too much ozone exposure can be harmful, so CARB compliant ensures safe air cleaning.

Room Coverage Area: The Purifier’s Range

Lastly, all air purifiers list their recommended “Room Coverage Area” in square feet. This tells you the maximum room size where the purifier can work effectively according to its specifications.

For example, a coverage area of 300 sq ft means the air purifier would do a great job cleaning the air in a 15ft x 20ft room or other similar sized space. But it likely couldn’t handle an entire basement or open floor plan efficiently.

Using a purifier outside its recommended room size means it won’t clean the air as quickly or completely. Always check that the unit’s coverage area matches your intended room’s square footage.

Match Specifications to Your Needs

As you can see, all those numbers, filter types, and certifications provide valuable insight into an air purifier’s performance abilities.

If you have severe allergies or asthma, you’ll want to prioritize higher CADR ratings for dust and pollen along with a True HEPA filter to capture those tiny irritating particles effectively.

For tackling persistent household odors or smoke, carbon filters with high gas/odor CARDs would be most important.

And for maintaining overall healthier indoor air quality, an Energy Star purifier with UV and pre-filters could be the perfect all-in-one solution.

The key is understanding your air quality needs, then cross-checking the various specifications to find the purifier models that provide the ideal level of pollutant removal, room coverage area, and energy efficiency.

With a little research into specifications and ratings, you can cut through the technical jargon and confidently select an air purifier that delivers the crisp, clean, refreshing air your home deserves!