Key Takeaways

• Remove the smell before you cover it. The EPA says eliminating individual pollution sources is usually the most effective way to improve indoor air.

• Move air out of the house. Exhaust fans that vent outdoors pull odors and moisture straight out of kitchens and bathrooms, and open windows bring in outdoor air when the weather allows.

• Most stale smells come from a short list. Trash cans, drains, the fridge, the washer and hamper, and fabrics like couches, rugs, and curtains.

• A musty smell usually means damp. The EPA advises keeping indoor humidity below 60%, ideally between 30% and 50%.

• Air purifiers help only with what's left. One with a substantial activated carbon filter can reduce lingering odors, but it doesn't replace cleaning and ventilation. Air fresheners only add chemicals of their own.

What makes a house smell fresh

A house that smells stale usually has one or two specific sources and air that doesn't move enough. Clean those sources, let outside air in, and keep the rooms dry, and the house ends up smelling of very little, which is what most people mean by fresh.

Do the work in order. The EPA's guide to improving indoor air quality names three basic strategies: source control, better ventilation, and air cleaners, and says source control usually works best. The steps below follow that order.

1. Find where the smell is coming from

Your nose stops noticing your own home's smell, so it's best to do this check right after you've been out. Sour or rotten smells usually point to food, trash, or a drain. A musty, earthy smell points to damp and possibly mold. A flat, closed-up smell usually means the room isn't getting enough fresh air.

2. Open windows and run the exhaust fans

Fans that vent outdoors remove contaminants directly from the room they're in, so they're worth running every time. Run the bathroom fan or crack a window while you shower, and use the range hood or open a window while you cook. The EPA also recommends venting clothes dryers and other moisture-producing appliances to the outside where possible. When the weather allows, open windows on opposite sides of the house for a while each day.

3. Empty and wash the trash and recycling bins

Food scraps sour fast. Take the kitchen trash out as soon as it holds food waste, even if the bag isn't full, and keep a lid on the can. Between bags, wash the inside with hot, soapy water, paying attention to the bottom where drips collect, and let it dry before the new bag goes in, since a wet can starts to smell again quickly. Rinse cans and jars before they go into recycling.

4. Clean the drains and the garbage disposal

Bathroom drains trap hair and soap scum, and that's what you're smelling. Pull out the stopper or drain cover, scrub it, and flush the drain with hot water.

In the kitchen, the rubber splash guard on a garbage disposal collects food on its underside; lift the flaps and scrub them with an old toothbrush and dish soap. A sewer smell from a drain that rarely gets used often means the water in its trap has dried out, and running water for a minute refills it.

5. Clear out and clean the fridge

Throw away spoiled or questionable food first. The USDA Food Safety and Inspection Service suggests washing the shelves and drawers with hot water and detergent, washing the interior, including the door gasket, with hot water and baking soda, and leaving the door open for about 15 minutes so air can circulate.

If the smell hangs on, the same USDA guidance suggests wiping the inside with equal parts vinegar and water, or setting fresh coffee grounds or baking soda loosely in a large, shallow container on the bottom of the fridge.

6. Keep the washer and laundry from going sour

Damp towels and gym clothes left in a hamper don't take long to sour. Hang them to dry before they go in the basket, and move clean loads into the dryer as soon as the cycle ends.

Front-loading washers hold water in the rubber door seal. Wipe the seal after the last load of the day, leave the door slightly open so the drum can dry, and run the machine's cleaning cycle as often as the manual recommends.

7. Wash and vacuum the soft furnishings

Fabric holds cooking and pet smells long after the source is gone. Wash bedding, throws, removable cushion covers, and pet beds following their care labels. Vacuum upholstery (including under the cushions), rugs, and carpets, and wash or air out curtains a few times a year, since they hang right where cooking smells drift.

8. Keep humidity in a healthy range

Musty smells come from damp. The EPA's guide to mold and moisture advises keeping indoor relative humidity below 60%, ideally between 30% and 50%. A digital hygrometer shows where your rooms sit, and a dehumidifier brings a damp basement back into range.

The EPA also says water-damaged areas and items should be dried within 24 to 48 hours to prevent mold growth. If a musty smell stays after the rooms are dry, mold may be hiding where you can't see it. The EPA names the back side of drywall, the underside of carpets and pads, and the inside of walls around leaking pipes as common spots.

9. Add an air purifier for what's left

Once the sources are gone, an air purifier can take care of lingering smells, but only the right kind. According to the EPA's guide to air cleaners in the home, most filters catch either particles or gases, not both. Odors are gases, so a HEPA filter alone isn't doing the work. For gases, the EPA points to an activated carbon filter, and says carbon filters can be effective provided the filter uses a large amount of material.

This changes what to look for in a purifier. The CADR numbers on the box rate particles only, and the EPA notes there are no widely used performance rating systems for gas removal, so the box won't tell you how a unit handles smells. Carbon filters need regular replacement like any other, and the EPA says research has not yet shown that plasma, photocatalytic oxidation, or UV light can remove gases effectively in portable home units.

A carbon purifier helps with leftover cooking smells or a room that held smoke or pet odor after the source has been cleaned. It won't fix a smell that keeps being produced, such as a dirty drain or mold in a damp corner. In the EPA's words, filtration does not replace the need to control pollutants and ventilate.

Why air freshener isn't the same as fresh air

Sprays and plug-ins cover a smell with a stronger one. The odor is still there, and the product adds chemicals of its own. The EPA lists air fresheners among household sources of volatile organic compounds (VOCs), and notes that levels of several organics average 2 to 5 times higher indoors than outdoors.

If you like a scented home, add the scent after the source is gone and keep a window cracked while you do.

Small habits that keep the house smelling clean

• Take food waste out daily. A full bag sitting overnight undoes a lot of cleaning.

• Do one fabric item a week. Doing curtains one week and cushion covers the next keeps the job small. More ideas live in our Air & Comfort section.

Frequently asked questions

Why does my house smell musty even though it's clean?

A musty smell usually comes from moisture, which cleaning doesn't touch. Check indoor humidity with a hygrometer and aim for the EPA's range of below 60%, ideally 30% to 50%. Then look for slow leaks and damp spots, since hidden mold can cause the smell.

Do air purifiers get rid of smells?

Some do, partly. Odors are gases, and the EPA recommends an activated carbon filter for gases, effective when it holds a large amount of material. A purifier with only a particle filter won't do much for smells, and no purifier fixes a source that keeps producing odor.

Does baking soda really absorb fridge odors?

USDA guidance lists an open, shallow container of baking soda or fresh coffee grounds as one option for a fridge that still smells after cleaning. It works best once spoiled food is gone and the interior has been washed.