How many bedroom air purifier makers publish CADR, noise in decibels, ozone and filter costs?

This guide is for: anyone in the US reading a bedroom air purifier's product page who wants to know which numbers makers usually print, which they leave out, and where to find the rest.

The page-by-page answers are in the survey CSV if you want to check or recount them.

What did a count of 26 makers' pages find?

Most of the 26 pages print room size, filter type and noise; about two in three print CADR and filter cost; fewer than one in three mention ozone.

We read 26 product pages on November 11, 2026, one for each air purifier marketed for bedrooms and sold to US buyers. All 26 loaded and could be read in full (survey CSV). We checked each page for the same seven facts, and the results fall into three groups:

• Stated by 20 or more of 26: room size (24), filter type (23) and noise in decibels (20).
• Stated by 17 to 19 of 26: how often to replace the filter (19), a CADR figure (17) and a filter price (17).
• Stated by 8 of 26: whether the unit makes ozone (8).

Source: survey CSV, 26 makers' US product pages read on November 11, 2026. Shares are rounded to the nearest whole percent.

Ozone stands apart from the rest: more than two in three pages say nothing about it either way. CADR and the cost of keeping a purifier running are the two facts most needed to compare units on paper. Both are in the middle group, so about one page in three leaves them out.

How was the count done, and what can it not tell you?

Each page was read once on one day, saved as read, and scored yes only where a quote in the page answered the question; no unit was handled.

We started with 26 air purifiers marketed for bedrooms and sold to US buyers. We read each one on the maker's own product page, not on a retailer listing. We saved every page as it stood when we read it, so later changes on the maker's site don't change the record. A page got a yes only where a line on the page itself answered the question. Anything vaguer counted as not stated. All 26 pages were read on November 11, 2026.

A yes means the maker states the fact, not that the figure is correct. This publication owns no test equipment, and no purifier was handled for this count. The count records what is printed and nothing more.

To check a figure from a product page, start with the agencies and directories in the last section of this guide.

What does a CADR figure tell you about a bedroom purifier?

CADR is the rate of filtered air in cubic feet per minute, and AHAM's rule asks for at least two-thirds of the room's floor area in square feet.

AHAM's standard for measuring an air cleaner's efficacy is called the Clean Air Delivery Rate (CADR). It indicates the volume of filtered air an air cleaner delivers, with separate scores for tobacco smoke, pollen and dust, and the higher the number, the faster the unit filters the air (AHAM Verifide). AHAM's rule of thumb is a CADR of at least two-thirds of the room's area, so a 10 by 12 foot room of 120 square feet should have a smoke CADR of at least 80 (AHAM). EPA gives the same advice: choose a portable air cleaner with a CADR large enough for the size of the room (EPA).

The sum takes one line:

Minimum smoke CADR = floor area in square feet × 2/3. A 12 by 14 foot bedroom is 168 square feet, and 168 × 2/3 = 112 cfm.

Two things raise that number. For wildfire smoke, AHAM recommends a smoke CADR equal to the room's size in square feet, and if your ceilings are higher than 8 feet, you need an air cleaner rated for a larger room (AHAM Verifide). EPA's guidance for setting up a cleaner air room starts from the same two-thirds rule (EPA).

9 of the 26 pages give you no CADR to do this sum with (survey CSV). On those pages, the rated room size is the only sizing figure left. The next section explains why room sizes from different makers are hard to compare.

Why does the room size on a purifier's page vary so much?

A room size on a product page depends on how many times an hour the maker assumes the air is cleaned, so the same unit can claim different rooms.

Room size is the most often printed item in the count. It appears on 24 of 26 pages, while CADR appears on only 17 (survey CSV). That means at least 7 pages give a room size with no CADR to check it against. This matters because one unit can be rated for very different rooms. Coway's product page for the AP-1512HH lists three room sizes for the same machine, one for each assumed number of air changes per hour:

Source: Coway's AP-1512HH product page (Coway), read on the same day as the survey.

The same page lists a smoke CADR of 233. If you run AHAM's rule backwards, 233 ÷ 2/3 = 349.5, or about 350 square feet. That's close to the room size Coway gives for 4.8 air changes an hour. The largest of the three room sizes is nearly five times the smallest, and all three describe the same purifier.

If a page gives a room size without saying how many air changes per hour it assumes, you can't tell which kind of number you're looking at. Treat a room size on its own as a claim to check, and size the unit by its CADR when the page gives one.

What does a noise figure in decibels leave out?

A decibel figure means little without the distance and fan speed behind it, so the lowest number on one page may not match another's.

Of the 26 pages, 20 state noise in decibels and 6 do not (survey CSV). A decibel figure is hard to use unless you know how it was taken. Sound gets quieter the farther you are from the source, and every purifier gets louder as the fan speeds up. That's why one machine can be described by several different numbers.

Coway's page lists a noise level of 24 to 53 dB(A) for the AP-1512HH (Coway). A review site measured the same model with a sound meter 3 feet away and recorded 38.9 dB at the lowest speed and 60.1 dB at the highest (HouseFresh). The two sources don't necessarily contradict each other, because the figures may have been taken under different conditions.

In a bedroom, the figure that matters is the noise at the fan speed you will run while you sleep. If a page gives only the lowest-speed number, check whether that speed still meets the two-thirds CADR rule for your room. A unit sized exactly to the room may need a louder setting to clean it. To see how much steady sound starts to affect sleep, read how loud a bedroom can be at night.

Why do so few makers say whether a purifier makes ozone?

Only 8 of the 26 pages say whether the unit makes ozone, though California has capped ozone from indoor air cleaners at 0.050 ppm since 2010.

Ozone is the least published item in the count: 8 of 26 pages say whether the unit makes ozone, and the rest say nothing (survey CSV). Silence doesn't mean a unit makes ozone. A purifier that only pushes air through a filter has no ozone to report, and its maker may not think to mention it.

Ozone still matters in a room you sleep in. EPA says to avoid portable air cleaners that intentionally produce ozone, a lung irritant. It also notes that air cleaners with electrostatic precipitators, ionizers, UV lights without adequate lamp coatings, or plasma may emit ozone (EPA).

California has the clearest rule. Since 2010, every indoor air cleaner sold in or shipped to California must meet ozone emission and electrical safety standards, with ozone emissions below 0.050 parts per million (CARB). CARB advises checking its list of certified air cleaners before buying any portable air cleaner (CARB).

The count looked for a plain statement. One example is Levoit's replacement filter page, which says its sleep mode runs with "zero ozone emissions" (Levoit). If a page is silent on ozone, look the model up on CARB's list before you put the unit next to your bed.

How do filter cost and replacement interval add up over a year?

Yearly filter spend is the filter price times the number of changes a year, and a page that prints only one of the two leaves the sum unfinished.

A filter price alone doesn't tell you what a purifier costs to run. You also need to know how often the filter is changed. The yearly cost is the two figures multiplied:

Filters a year = 12 ÷ months between changes. Yearly filter cost = filter price × filters a year.

Levoit's filter page recommends replacing the filter every 6 to 8 months (Levoit). That works out to 1.5 filters a year (12 ÷ 8) at the long end and 2 filters a year (12 ÷ 6) at the short end. Some units use more than one kind of filter. Coway's page gives a 6-month life for the deodorization filter and a 1-year life for the HEPA filter (Coway), so a year of use takes two deodorization filters and one HEPA filter.

In the count, 17 of 26 pages print a filter price and 19 print a replacement interval (survey CSV).

Since the two groups must overlap by at least 17 + 19 − 26 = 10 pages, between 10 and 17 pages give both halves of the sum. On every other page, the missing figure has to come from a parts page or the manual.

Replacement intervals are estimates. Levoit's US store recommends a change every 6 to 8 months but says homes with heavy exposure to pet fur, dust or smoke may need one sooner (VeSync). If you run the purifier all night, every night, plan on the short end of the stated range.

Where can you check a figure the maker does not print?

AHAM's Verifide directory lists certified CADR figures and CARB lists certified air cleaners, so a missing number can often be found elsewhere.

EPA does not certify air cleaning devices or recommend devices or manufacturers (EPA), so you'll need other sources to fill the gaps.

EPA notes that there are no widely used performance ratings for air cleaners designed to remove gases, and that the CADR rating covers particles only (EPA). Both CARB and AHAM keep lists of air cleaners tested and shown to emit little or no ozone (EPA).

Some limits of a purifier don't show up in any figure on its page. EPA cautions that air cleaners alone cannot ensure adequate indoor air quality, especially where pollution sources are significant and ventilation is poor (EPA). A filter doesn't remove the carbon dioxide you breathe out, so a stuffy room with the door shut is a ventilation problem. The stale air check shows how to read one, and the guide to ventilating a bedroom in winter covers bringing in fresh air without losing the heat.

Common questions

What CADR does a 10 by 12 foot bedroom need?

That room is 120 square feet, and AHAM's rule calls for a smoke CADR of at least 80 (AHAM). Choose a higher CADR if the ceiling is above 8 feet or if you're dealing with wildfire smoke.

Does a purifier with only a filter make ozone?

A filter on its own doesn't produce ozone. EPA names electrostatic precipitators, ionizers, some UV lights and plasma as features that may emit it (EPA), so check whether the unit has any of these.

Does CADR measure odors and gases?

No. CADR covers particles only, and a unit with a high CADR plus an activated carbon filter can handle both particles and gases (EPA).

How quiet should a bedroom purifier be?

No agency sets a noise limit for purifiers. Compare figures at the fan speed you'd sleep with, and look for a stated distance. Six of the 26 pages counted give no decibel figure at all.

How often do purifier filters need replacing?

It depends on the model. Levoit states 6 to 8 months for the Core 300 filter, and Coway gives 6 months and 1 year for its two filters. In our count, 19 of 26 pages state an interval (survey CSV).

Can I see the page-by-page data?

Yes. The survey CSV lists all 26 pages read on November 11, 2026, with a yes or no for each of the seven facts.