The Usual Indoor Triggers
| Trigger | Where it lives | What reduces it |
|---|---|---|
| Dust mites | Bedding, mattresses, upholstery | Hot weekly washes, zippered covers, lower humidity |
| Pet dander | Floors, furniture, return grilles | Pets out of the bedroom, better filtration |
| Mold | Damp areas, the AC coil, wet insulation | Fix moisture, humidity 30 to 50 percent |
| Cockroach allergens | Kitchens, food areas | Covered food and garbage, baits and traps |
Start in the Bedroom
You spend a third of the day there. The Asthma and Allergy Foundation of America advises washing bedding, uncovered pillows and stuffed toys weekly in water at 130°F or hotter, and using zippered allergen-resistant covers on pillows, mattresses and box springs. It also notes there is no such thing as a hypoallergenic pet and recommends keeping pets out of the bedroom. Homes with shedding pets get more from the pet hair duct page.
The Heating and Cooling System's Part
The system doesn't create allergens, but it moves them. Two settings matter most. The EPA recommends using the highest efficiency air filter your system's manufacturer allows and changing it on schedule. It also recommends indoor humidity between 30 and 50 percent, which works against both dust mites and mold. The indoor air quality guide covers filtration, ventilation and humidity together.
Do the Ducts Matter?
Sometimes. The EPA says duct cleaning has never been shown to prevent health problems, and a light layer of household dust in ducts poses no known risk. Cleaning helps when the ducts hold mold, pest debris or heavy dust that blows into the rooms. The duct cleaning for allergies page explains how to tell, and the dust guide covers dust at the registers. For symptoms themselves, talk with a doctor or allergist.