How to clean the air in your home: 8 ways that work

Key Takeaways

• The EPA says removing a pollution source is usually the most effective way to improve indoor air, ahead of filtering it.

• Kitchen and bathroom fans that vent outdoors deal with cooking fumes and shower moisture for the price of the electricity.

• A portable HEPA purifier is sized correctly when its smoke CADR is at least two-thirds of the room's floor area in square feet.

• The EPA recommends keeping indoor humidity below 60%, and ideally between 30% and 50%.

Where indoor air pollution comes from

Americans spend about 90% of their time indoors, and the EPA reports that some pollutants are often two to five times more concentrated inside than outside. Most of it comes from ordinary life: cooking, showering, cleaning sprays, candles, and dust that settles and gets kicked back up.

The first four steps cost little or nothing, and the last four involve a filter or a device.

1. Remove the source

The EPA calls source control the most effective way to improve indoor air quality, and it often costs less than adding ventilation. In a typical home that means no smoking indoors, fewer candles and less incense, and fragrance-free cleaning products where they're available. The American Lung Association recommends finding and cleaning the cause of a smell. If you still want a seasonal scent, our holiday air freshener roundup covers how to use one with the window cracked and pets in mind.

2. Open windows when the outdoor air is good

Bringing in outdoor air dilutes what builds up inside, and the EPA lists opening windows and doors as a simple way to do it when the weather permits. Check the local air quality index on AirNow.gov first. On high-pollen days or when wildfire smoke is in the area, the EPA advises keeping windows closed.

3. Run the range hood every time you cook

Cooking releases fine particles, and gas stoves add nitrogen dioxide. The EPA recommends an exhaust fan vented to the outdoors over gas stoves, and notes that homes with gas stoves often have higher indoor levels than outdoor ones. Some hoods only recirculate air back into the kitchen, so it's worth checking where yours actually vents.

4. Use the bathroom fan when you shower

Steam that lingers in a bathroom is moisture that mold can use. The EPA's mold guidance is to run the bathroom fan or open the window while showering, and to vent clothes dryers and other moisture-producing appliances to the outside where possible.

5. Upgrade your HVAC filter

If your home has central heating or air, its filter treats the whole house every time the system runs. The EPA suggests a filter rated at least MERV 13, or as high as your system can handle, and notes that manufacturers typically recommend replacing it every 60 to 90 days.

6. Add a HEPA purifier in the rooms you use most

Portable air cleaners with HEPA filters remove particles such as dust, pollen, and smoke from a single room. The number to compare is CADR (clean air delivery rate): the higher it is, the larger the room a unit can serve, according to the EPA's guide to air cleaners in the home. AHAM's rule of thumb is a smoke CADR of at least two-thirds of the room's square footage, so a 200 sq ft bedroom calls for a smoke CADR of 132 or more.

Look for a model on the California Air Resources Board's certified list, which caps ozone emissions at 0.050 parts per million. Skip so-called ozone generators. The EPA states that no federal agency has approved them for use in occupied spaces.

7. Keep humidity between 30% and 50%

Air that's too damp feeds mold and dust mites, and air that's too dry is uncomfortable to breathe. The EPA recommends staying below 60% relative humidity, ideally between 30% and 50%. A basic hygrometer shows where your home sits. A damp basement usually calls for one of the dehumidifiers we've compared, while dry winter air calls for a humidifier; our cool mist vs. warm mist guide explains which type suits which room. The EPA recommends cleaning portable humidifiers every third day and filling them with low-mineral water such as distilled.

8. Clean in ways that trap dust

Dry dusting and a leaky vacuum push settled particles back into the air. The American Lung Association suggests a vacuum with a HEPA filter and a sealed system, plus a damp mop or cloth that traps dust as it wipes.

Do houseplants clean indoor air?

Not in any amount you'd notice. A 2019 review by researchers at Drexel University found it would take between 100 and 1,000 plants per square meter of floor space to match the air exchange of a building's ventilation system or a couple of open windows. Keep them for how they look.

Frequently asked questions

Is an air purifier enough on its own?

No. A purifier handles particles in one room, but it can't keep up with a smoky stove or a damp bathroom. Source control and ventilation come first, and a purifier covers what's left.

What humidity should my home be?

Between 30% and 50%. The EPA recommends staying below 60% to limit mold, and a hygrometer is the easiest way to check.

Are ozone air purifiers safe?

The EPA advises against them. Ozone can damage the lungs when inhaled, and no federal agency has approved ozone generators for use in occupied spaces.