How to Find (and Close) Your Home’s Fresh Air Intake

If you’re in an area affected by wildfire smoke — whether it’s the current haze blanketing the east coast or the entire fire season in the west — you’re probably spending more time indoors to avoid bad air quality outside. Common practices for protecting indoor air quality include closing doors and windows and using an air purifier ( do-it-yourself ). Another recommendation from the Centers for Disease Control and Prevention (CDC) is to turn off the fresh air inlet to your air conditioner, so how do you know if your home has one and how to turn it off?

What is a fresh air intake?

A fresh air inlet does exactly what you’d expect: it brings fresh air into your home from the outside. Not only does this improve indoor air quality by reducing dust and preventing the buildup of other pollutants, but it also keeps your stove and HVAC system efficient and can reduce energy costs.

However, when outdoor air quality is poor , fresh air intake can do more harm than good.

How to find and close fresh air vents

Most new homes have one or more air intakes in accordance with building codes. The vents are often metal hoods or plastic pipes located outside on the ground side of your house, although they can also be on the roof or in the attic. You may also find grilled inlets near or behind a stove or other gas appliances.

To determine if the vent is for air intake (not exhaust), place your hand under it while the oven is operating. If you feel air being drawn in, this is a sure sign. The air intakes also have screens and the exhaust valves have flaps.

In most cases , closing an air intake is as simple as switching a damper to the closed position by turning a knob or knob, or turning off a fan. Alternatively, if your HVAC system has a “recycle” mode , turn it on.