Lots of new build homes are well insulated and relatively air-tight and for a wood burner to work properly, it needs a constant supply of air. A direct air kit may be the solution you need if your wood burner isn’t likely to receive the air supply it needs for efficient combustion. In this guide, we'll explore what an outside air kit is and why it is essential for maintaining a healthy and efficient ventilation system in your home. 

Contents

What is an Outside Air Kit?
Why is Closed Combustion Important for a Wood Burner?
Which are the Best External Air Compatible Stoves?
How is an Outside Air Kit Fitted?
When Might I Need an External Air Kit?

An outside air kit is a component that is attached to a log burner to bring in fresh air from the outside directly into the stove. These kits have been given a few different names over the years and can be commonly defined as direct air kit, external air ventilation kit or external air kits.

An outside air kit typically consists of aluminium ducting or pipe work that connects to the outside of the home and allows fresh air to be drawn into the combustion chamber of your wood burning stove. This fresh air helps to maintain proper airflow and ventilation for your stove and also throughout the home. An outside air kit is especially important in tightly sealed or well insulated homes which is often the cast for newly built properties.

An outside air kit is important for your home's ventilation because it helps to bring in fresh air from the outside into your stove. This fresh air is essential for efficient combustion to take place within your log burner. Without an outside air kit, your stove will rely solely on recirculating indoor air, which in some cases can lead to difficulty in lighting and maintaining a fire within your wood burner. Overall, an outside air kit is essential for maintaining a healthy and comfortable living environment in your home.

At this point, it is worth knowing that only certain wood-burning stoves are compatible with outside air kits. You’ll find a filter on our website labelled ‘external combustion’ to find all the wood burners that are direct air compatible also known as room sealed stoves.

Wood-burning stoves typically obtain their air from the room where they are located. They will draw air into their firebox using air controls and vents that are usually located on the front of the stove. These vents control how much air enters the stove and in turn, this controls how fiercely the fire burns inside the stove, effectively adjusting the heat output to the room. However, it’s not always practical or suitable for a wood-burning stove to draw the oxygen it needs from the room in which they are fitted.

For these cases, a wood burner suitable for external combustion would need to be purchased and by clicking on the link above you’ll find all the popular and sought after models that are direct air compatible.

Not all stove manufacturers supply direct air kits so we’ve taken the opportunity to list some of the products you can buy here.

As we’ve already mentioned, an external air kit will usually consist of either a solid or flexible tube made from aluminium. This tube connects to a spigot on the back of the stove or underneath it and the tube then passes through an external wall to the outside where a grill will be fitted. This pipe or tube can be fitted to the spigot of your stove with a specific connector or a simple jubilee clip and the grill fitted on your outside wall prevents debris from the outside entering your home.

Not every wood-burning stoves requires an outside air kit, especially for log burners that have a heat output of 5kW or less. One of the main reasons most people need to use an external air kit with their wood-burning stove is when the room in which their stove is located has insufficient ventilation. Direct ventilation is not a requirement if you have a stove with a nominal output of less than 5kW and your home was built before 2008. However, if you’re looking to buy a wood burner with a larger heat output than 5kW or live in a newly built home there are some regulations you will need to follow.

There are a number of other reasons why you might require an external air kit, here are the main ones you should be aware of.

1. The room where your stove is being installed does not have a fixed vent in place.
2. You live in a home which uses Mechanical Ventilation Heat Recovery (MVHR) technology.
3. Your home has been designed and built to PassivHaus standards.