Add a Fresh Air Intake to Your Wood Stove to Avoid Toxic Air

Too often, wood burning boilers and stoves are installed without a dedicated fresh air source. Stoves without a source of fresh air can badly pollute your home's air with dangerous flue gases--leading to asthma or other illnesses. Here are several solutions.

While doing some research on fresh air intake for wood boilers, I noticed an old illustration of a do-it-yourself fresh air return. It reminded me how important it is that wood burners of all vintages include fresh air intake ports. If you must burn wood, one of the dirtiest types of combustion, at least make sure you’re not introducing toxic particulate to your own home. And start saving for a non-polluting heat pump that runs on renewable solar, wind or hydro energy to phase out your old dinosaur of a wood heating source.

Image Credit: Building America

Wood Stoves: Air Needed. Some building codes require a fresh air intake with a wood stove. The reason for this is sound. When a wood stove has no fresh air source, it depressurizes the space around it. Not only may this result in backdrafting of oil or gas boilers, it could also pull fumes from gas cooktops or bathrooms into living areas. Perhaps worst of all, it can cause the fine smoke particles from the stove to gust into the home—or to enter through exterior wall gaps and window cracks.

Add-On Intake. Some modern wood stoves have fresh air intakes built in, but many do not. In the latter case, it’s possible to add one using a kit such as the one shown above.

One low-tech solution is the Duravent wood stove thimble (shown), which allows fresh air to come in at the point where the woodstove or pellet stove pipe exits the wall. This should preheat the air to some degree and requires no additional piping.

Another more contained way to bring in some air to fuel the combustion in your wood stove is to install a passive vent that is pressure sensitive directly through the wall, near the woodstove. A company called Ecovent also makes “smart” pressure balancing vents that might do the trick.

If you’re lucky, your wood stove already has a flange already installed, just wanting for a 4-inch air intake pipe. Put the vent inside the duct, near the outside wall where the air will be drawn from.

Air Intake. Although it’s not especially sleek in design, the DuraVent PVP-WTI PelletVent Pro Wall Thimble Air Intake Kit provides fresh air to wood pellet burners.