Indoor air buying guides
Which air purifier actually clears your room, which monitor's sensor reads PM2.5 and CO2 properly, how big a dehumidifier your basement needs, and what MERV rating your furnace can take. Every guide shows the certified figures, the sources and the arithmetic behind the pick.
The numbers behind every pick
The guides most readers need first.
Buying guideSix air purifiers that earn their place on certified numbers: the right CADR for the room, sensible filter costs, and no marketing-only claims.
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CalculatorEnter your room's size and ceiling height to get the smoke CADR you need for allergies, smoke or wildfire days, and how many air changes an hour your current purifier delivers.
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Buying guideA monitor is only as good as its sensors. We picked the ones with laser particle sensors, true NDIR CO2 and, where it exists, independent accuracy testing from South Coast AQMD.
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Buying guideOur top pick is the Midea Cube 50: a certified 49.67 pints a day at ENERGY STAR's 2.01 L/kWh, with a large bucket and a compact, extendable body. Here are six picks by job.
Read the guideFine particles, measured in micrograms per cubic meter, on the EPA's Air Quality Index scale for a 24-hour average. Source: EPA, 2024 AQI update.
PM2.5 explainedGood
0 to 9.0
Moderate
9.1 to 35.4
Unhealthy for sensitive groups
35.5 to 55.4
Unhealthy
55.5 to 125.4
Very unhealthy
125.5 to 225.4
Hazardous
225.5 and up
Certified figures first
CADR from AHAM Verifide, ozone from the CARB list, efficiency from ENERGY STAR, limits from the EPA.
A clear pick
Each guide names what we would buy, for which room, and what to skip.
Sources on every page
Every guide links the maker documents and agency pages it was built from.
New and updated buying guides, reviews and explainers.
Filter-only purifiers do not make ozone. Ozone generators are designed to, and some ionizers and other electronic purifiers make it as a byproduct. Here is how to tell which is which.
A nursery monitor is most useful for temperature, humidity and ventilation, with PM2.5 as a bonus. It does not replace a smoke or CO alarm. Here is what to track and what to buy.
A home monitor is a bundle of small sensors, each good at one thing. Knowing which sensor sits behind each number tells you which readings to trust and which to treat as a trend.
The MA1201 is a rolling console that humidifies an open house from one spot. It needs space, a wick every 30 to 60 days and careful cleaning, but nothing portable moves more water.
The View Plus is the most complete home air monitor Airthings makes: radon plus particles, CO2 and VOCs, on batteries or USB-C. It is expensive, and worth it mainly if you want radon too.
The Wave Enhance is Airthings' small, battery-powered monitor for bedrooms and offices. Unlike the old Wave Mini, it measures CO2 with an NDIR sensor. It does not measure radon or particles.
