Cleaner air at home, explained with the evidence.
Plain-language guides to purifiers, filters, detectors, and humidity, built on published research. We say what works, what doesn't, and where the evidence is thin.
Browse topics Size a purifierTopics
We publish one topic at a time, in depth. Topics marked "coming soon" are in progress.
Wildfire smoke
Do purifiers work, how to size one, HEPA vs. carbon, and DIY box-fan cleaners.
HVAC and furnace filters
MERV ratings explained, what your system can handle, and how often to replace filters.
Basements
Moisture, mold, and musty air: what a dehumidifier fixes and what a purifier can't.
Radon tests and monitors
How to test, how to read results, and why filters don't remove radon.
Carbon monoxide alarms
Where to install them, what to look for, and when to replace them. Purifiers do not remove CO.
Humidifiers and dehumidifiers
Target humidity, sizing, and keeping the units themselves clean.
Babies and kids
Nursery air, quiet operation, safe placement, and devices to avoid around infants.
Older adults
Easy-to-use equipment and protecting higher-risk people during smoke and pollution events.
Allergies, pets, and cooking
Pollen, dander, and kitchen fumes: matching the filter and ventilation to the problem.
Wildfire smoke guides
Each guide summarizes published research, links to the sources, and says where the evidence is weak.
Do air purifiers work for wildfire smoke?
What field studies show about PM2.5 reduction, and what is still uncertain.
What size air purifier do you need?
The smoke CADR rule, with a room-size table.
HEPA vs. carbon filters for smoke
Particles, gases, and how much to trust the marketing claims.
DIY box-fan cleaner vs. a store-bought purifier
What EPA lab tests found, plus noise, safety, and filter changes.
Air purifier standards around the world
HEPA grades, CADR in different units, China's CCM rating, and research from Canada, Australia, and Southeast Asia.
Air purifier calculator: room fit and 5-year cost
Specs are manufacturer-reported. Coverage uses the EPA and ENERGY STAR guideline that smoke CADR should be at least two-thirds of room area (8 ft ceilings).
Total = purchase price + 4 years of replacement filters (the first filter ships with the unit) + electricity at typical power draw.
How we work
Our guides are based on peer-reviewed studies, government agencies (such as the EPA, Health Canada, and public health institutes), and published standards. Every guide links to its sources and notes where the evidence is limited or mixed.
Product comparisons currently use manufacturer-reported specifications. We are setting up our own testing, and we will publish our method, equipment, and raw results before any product page says "tested."
We never accept payment for rankings. If a product was sent to us for free, we will say so on its page.
Calculator formulas: air changes per hour = smoke CADR × 60 ÷ (room area × 8 ft ceiling). Five-year electricity = watts ÷ 1,000 × hours per day × 365.25 × 5 × your rate.
Prices and filter costs change, so check the retailer's page before you buy. Spot an error? Email us and we will correct it and note the change.
FAQ
Will an air purifier fix a musty basement?
Usually not on its own. Musty air generally comes from moisture, so the fix starts with finding the water source and controlling humidity. A purifier can help with airborne particles once moisture is under control.
Does a HEPA filter remove radon or carbon monoxide?
No. Both are gases that HEPA filters do not capture. Radon calls for testing and, if levels are high, professional mitigation. Carbon monoxide calls for working CO alarms and properly maintained fuel-burning appliances.
Do I need a bigger purifier than my room size suggests?
If you have smoke, pets, or allergies, more CADR cleans the air faster and lets you run the unit at a quieter speed.
Why is this a .org if you earn commissions?
We chose the name for the mission, not to suggest we are a charity. IndoorAirLab.org is a for-profit, independent site funded by affiliate commissions.