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Do All Pellet Stoves Require Outside Air?

Pellet stoves burn a fuel source (pellet fuel) to create a fire and heat its surroundings. Now, fire requires a steady air supply because, without oxygen, it’ll cease to burn. So this brings us to the question – do we need to supply outside air to pellet stoves?

All pellet stoves don’t require outside air, but I recommend it for efficient burning. Also, you have to fit your pellet stoves with an outside air intake vent if your local building regulations mandate it. Without outside air, there’s a risk the pellet stove fire will reduce indoor oxygen levels.

This article will give you an in-depth look at how indoor air and outside air differently influence how your pellet stoves function. This information will help you understand why most manufacturers recommend and many localities mandate the use of outside air for pellet stoves.

Should You Use Outside Air for Your Pellet Stove?

There are no strict nationwide rules for pellet stoves to have dedicated vents for outside air intake. Almost all pellet stoves come with an outlet for attaching an outside air kit, and manufacturers highly recommend using outside air instead of indoor air. 

Furthermore, many local building regulations mandate the use of an outside air intake vent for pellet stove owners.

I’d also recommend putting in the extra effort (or investment if necessary) and switching to using outside air instead of indoor air for your pellet stoves.

I’ve shared a detailed look at how pellet stoves use indoor air for burning fuel in the following section. These details should help you better understand why using indoor air is inefficient. I’ve also highlighted a few benefits of using outside air instead of indoor air.

How Pellet Stoves Use Indoor Air

Pellet stoves might (or might not) have a dedicated vent for air intake, but they must have an exhaust vent or flue for eliminating the waste air formed inside due to combustion

As waste air leaves the stove, it creates a vacuum that sucks in the fresh air from its surroundings. So, even if you don’t attach a dedicated air intake vent, your stove will still function properly using the indoor air without needing any extra apparatus.

However, as the stove is sucking up the indoor air, using it for combustion, and exhausting it as waste air, the room will feel suffocating as oxygen levels dip. Dropping oxygen levels is more of a concern in modern buildings with air-tight construction.

As such, some local building regulations mandate the use of outside air for pellet stoves. 

Also, most, if not all, manufacturers have stated that if the pellet stove doesn’t have a direct air intake vent, the room or space in which it’s in must have a ventilation system to replenish the air lost to combustion.

Benefits of Using Outside Air for Your Pellet Stove

Should you still use outside air for your pellet stove if no one forces you?

You don’t necessarily have to connect your pellet stove with an outside air intake vent unless it’s specifically required for that model or stated in your local building regulations. 

Even if it’s not mandatory, I’d suggest that you consider connecting your pellet stove with an outside air intake as it offers multiple advantages.

Here are the three main benefits of using outside air for your pellets stove:

  • Pellet stoves burn more efficiently using outside air.
  • Pellet stoves won’t use the warm indoor air.
  • The indoor oxygen level stays intact.

Let’s go over each of these points in more detail.

Pellet Stoves Burn More Efficiently Using Outside Air

Pellet stoves are automated heating appliances where all their parts work automatically and in tandem to maintain the desired room temperature.

When you add an outside air kit to your pellet stove, it can now take in as much (or as little) air/oxygen from the outdoors as it needs to fuel the fire and maintain a steady and efficient burn.

This process empowers the pellet stove to generate an efficient burn with complete control over the fuel and air requirements, which wasn’t possible when passively sucking in the indoor air.

Pellet Stoves Won’t Use the Warm Indoor Air

Let’s say your pellet stove is using the indoor air instead of the outside air, and you have an external air vent in your room for a steady supply of fresh air.

The stove takes in the air inside the room to fuel the fire, heat the room, and then exhaust the waste air outside. As this process continues, your room will fill up with warm air.

But now, the stove will suck in this warm indoor air as an intake to keep the fire burning and then exhaust it outside. In its place, the vent in your room will bring in the cooler fresh air, which your stove has to warm up again.

So as you can see, by using indoor air, you’ll inevitably start using the warm air produced by the stove and exhaust it outside, making the process sub-optimal. 

What’s more, cooler air from outside will enter your room through its ventilation system, making it challenging to maintain your desired room temperature.

All these instances make using indoor air for your pellet stove very inefficient.

The Indoor Oxygen Level Stays Intact

Fire needs oxygen to burn, and when you’re using the indoor air to power your pellet stove, you’re affecting the indoor oxygen levels. If the room or space lacks sufficient ventilation, the oxygen level inside the area will gradually start to go down, which can become a big concern.

However, you don’t need to worry about this if you use outside air.

It becomes a sealed and isolated system when you connect the pellet stove with an outside air intake vent. As a result, the air quality in your room will stay intact, besides the fact that it’ll get warmed up to your desired temperature.

Key Takeaways

All pellet stoves don’t specifically need outside air to function correctly. However, many people recommend it as burning with outdoor air is more efficient, doesn’t use the warm indoor air, and keeps the oxygen levels intact. 

Still, you might need to use a dedicated outside air intake vent for your pellet stove if your local building regulations mandate it.


  • Steve Rajeckas

    Steve Rajeckas is an HVAC hobbyist with an avid interest in learning innovative ways to keep rooms, buildings, and everything else at the optimal temperature. When he's not working on new posts for Temperature Master, he can be found reading books or exploring the outdoors.

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