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What Is an External Air Kit for a Wood-Burning Stove?
Nothing beats the warm, fuzzy feeling of gathering around a crackling, cosy wood-burning stove on a chilly evening. But keeping your trusty stove burning at its best can be tricky in the airtight, well-sealed homes we build today. That's where the convenient and reliable external air kit comes in, ensuring your stove operates at its peak performance without hassle!
This clever invention is like an oxygen mask for your stove, allowing it to breathe in fresh, cool air from outside to get the fire firing on all cylinders. Read on, and we'll explain everything you need about external air kits: what they are, when you need one, and how they get your stove off to a smoking start.
What is an external air kit, exactly?
Simply put, an external air kit is a set of components that allows your wood-burning stove to draw in fresh air from outdoors rather than inside the home. It diverts the air supply from the room and directly from the outside.
The main pieces are:
- An adaptor that fits onto the back of the stove, where it can connect to the ducting
- Flexible aluminium ducting that runs from the outside, through the wall and into the stove
- An external wall vent or grille that sits discreetly on the outside wall
- Connectors, seals and clips to join the parts together and seal up any gaps
Once installed, it works like this: when you light up your stove, instead of sucking air from your lounge to feed the fire, it pulls in fresh air through the ducting from the vent outside. This makes for excellent combustion and maximum heat output from the stove.
How is an external air kit installed?
Installing an external air kit is a straightforward process. The kit usually consists of either a solid or flexible tube that connects to a spigot on the rear or underneath the stove and then passes through an external wall of your home. It's a simple and manageable task that any homeowner can confidently undertake.
The beauty of the external air kit lies in its adaptability. How the tube connects to your stove varies depending on the kit you buy. Some kits have special connectors, while others use a Jubilee clip. This adaptability ensures that the kit can be easily integrated into your specific stove setup, providing a secure and reliable solution.
The other end of the tube (which emerges from the external wall of your home) is usually capped with a grill to prevent detritus or small animals from getting into the vent.
Partial sealed vs total sealed vs leak sealed
There is an important point to note when it comes to the installation of an external air kit – you can install the air kit in a partially sealed, totally sealed, or leak-sealed configuration:
Partial sealed:
In a partially sealed configuration, the external air kit will provide most, but not all, of the required air for the stove. The remaining air is drawn from the room where your stove is installed.
A partially sealed configuration is acceptable for homes with some existing ventilation but not enough to run the stove entirely. This typically covers homes built before the early 2000s, when air permeability criteria were added to the Building Regulations.
Total sealed:
The external air kit will provide all the air required to operate the stove in a totally sealed configuration.
A total sealed configuration is ideal for much newer homes with low air permeability levels.
Leak sealed:
In a leak-sealed configuration, the external air kit will provide all the required air for the stove.
This type of external air kit installation is often only used in PassivHaus homes, which are airtight and unable to provide an air supply from within the room where the stove is located.
Note – always follow the manufacturer’s instructions when installing an external air kit and wood-burning stove.
When do you need an external air kit?
Building regulations in the UK require that homeowners fit any wood-burning or multi-fuel stove over 5kW heat output with an external air supply in homes built before 2008. All stoves in homes built after 2008 require either an air vent or external air intake, regardless of heat output. Without it, the stove may struggle to draw sufficient air for clean, efficient burning.
Even in older homes, a stove can benefit from an external air kit. Today's properties are built much tighter and better sealed than decades past. Where an old, draughty cottage had air to spare, modern homes trap air inside. Especially if you have double glazing and insulation, your stove might be gasping for oxygen! An external air kit can help your stove operate more efficiently, saving you money on fuel costs and reducing the risk of indoor air pollution.
But does every wood-burning stove require an external air kit? In short, no.
Most people need an external air kit with their wood-burning stove when their living room has insufficient ventilation.
The types of scenarios in which an external air kit is required include:
You don’t have a non-closable vent in the room you are placing the stove
Today's new-build homes are required to be more energy-efficient than ever before. However, that energy efficiency is usually achieved at the expense of a building's air permeability. Air permeability refers to the amount of air that can pass through a building's fabric, and a lower air permeability means less air leakage and better energy efficiency.
In other words, buildings are becoming increasingly airtight – with many house builders no longer including non-closable vents within the fabric of the building.
While this is great for keeping warmth trapped within your home's walls, installing a wood-burning stove is more challenging.
The Building Regulations stipulate that solid-fuel-burning appliances (like log burners) require the installation of a 'non-closable vent in an external wall'.
The traditional solution was to install an air vent into one wall of the room where your stove is. However, there's no getting around the fact that this leaves an open hole in the room's wall. That's not an appealing prospect for many homeowners. So, using an external air kit becomes the best solution.
You live in a home which has been built to Passivhaus standards
An increasing number of people are building their homes to Passivhaus standards.
What is Passivhaus? Passivhaus refers to a set of standards designed to create radically energy-efficient homes. The heat flow in, out, and around the house is strictly regulated, creating a nearly airtight home.
Suppose you intend to install a wood-burning stove in a Passivhaus. This is entirely possible in that case, but you'll need to use an external air kit. This air kit will need to be installed in a ‘leak sealed’ configuration so that your stove is completely sealed from the room in which it is located.
To achieve the best result, we recommend looking for wood-burning stoves that have been DIBt tested. This test assesses the effectiveness of a wood-burning stove's room seal, particularly the airtightness of the stove's door.
You live in a home which uses Mechanical Ventilation Heat Recovery (MVHR)
MVHR is a technology which, as the name suggests, involves mechanically blowing air through your property via heat exchangers.
This has the benefit of putting fresh air into your home while retaining the heat already used—thus reducing your overall heating bills.
However, as you can imagine, mechanically pushing air around your home can negatively impact internal air pressure.
Air pressure is crucially essential to the proper functioning of a wood-burning stove. Disturbing this air pressure can make it difficult, even impossible, for a stove to light and keep burning efficiently.
If you intend to install a log burner in a home that uses MVHR, you must use an external air kit. This will prevent your stove from being affected by changes in air pressure within your home.
In a home with MVHR, it is recommended that you install an external air kit in a leak-sealed configuration.
Your stove is being installed in an open-plan area with an extractor fan
Are you planning to install your stove in an open-plan area, such as a living room and kitchen combo? If you have an extractor fan in the area where you wish to install your stove, an external air kit is required.
This is because if you’re using your stove and the extractor fan at the same time, the extractor fan won’t just do its job of extracting moist air when cooking - it’ll also take vital air for your stove out of the room, making it harder to keep the fire going.
With an external air kit, you can cook and use your stove simultaneously, without any interference from the extractor fan. While the fan in the kitchen removes surplus air from your open-plan area, your stove continues to draw air in directly from the outside, keeping your home warm and toasty.
The components up close
Now, let's look at the critical pieces of an external air kit in more detail…
The adaptor
This starting point allows ducting to be attached to the rear of the stove. The ducting is usually a subtle flat piece designed not to disrupt the stove's appearance.
Adaptors come in set sizes like 80mm or 100mm diameter – this must match the stove and ducting. They easily screw or bolt onto a standard outlet on the back of the stove. Stoves over 5kW will likely have this adaptor pre-installed and ready to go.
The ducting
This flexible aluminium pipe directly carries fresh air from the great outdoors into the hungry stove.
Ducting can be purchased in convenient 1-metre and 3-metre lengths. It then bends and turns quickly to route the back of your stove out through the wall and to the outside vent—much more straightforward than messing around with rigid metal ducts!
The ducting attaches via simple connectors or collars that tighten to make a super-secure, airtight seal. Any leaks could affect the stove's performance, so all joints must be fitted appropriately.
The external wall vent
This unassuming little vent fits flush with the exterior wall of your home. It allows the ducting to pass from the adaptor outside.
External vents come in colours like brick red, grey, and black to blend discreetly with different wall finishes. They can be surface mounted over the hole or recessed into the brickwork.
The vent must have a grille or cover to prevent outdoor debris or creatures from finding their way inside through the ducting—we definitely don’t want any confused pigeons in the living room!
Our top external air-compatible stoves
Need an external air-compatible stove for your home? Here are our top three recommendations:
Woodford Pankhurst Medium
Immerse yourself in the elegance and excellence of the Pankhurst Medium stove from The Woodford Collection. This masterfully crafted 5kW wood-burning stove combines classic style with modern technology for an unforgettable warming experience.
The panoramic glass window offers mesmerising views of the dancing flames within. The Pankhurst’s precision engineering ensures outstanding 78.5% efficiency, maximising heat output from every log while reducing your carbon footprint.
External air compatible for optimal performance
Notably, the Pankhurst stove is compatible with the external air kit. This means you can install it with an external air supply even in today's airtight, highly insulated homes. Providing the stove with a direct source of fresh external air allows it to achieve optimal combustion temperatures for maximum efficiency and heat output.
By removing the need for the stove to compete for air from the room, an external air kit is often mandatory for the best performance in modern properties. The Pankhurst is ready to integrate seamlessly with an air kit for the perfect heating solution.
Bring the warmth of traditional stove charm into your modern lifestyle
With its timeless styling and innovative technology, the Pankhurst Medium stove from Woodford is the perfect way to enjoy the nostalgia of natural wood burning in a contemporary home. Experience sustainable warmth wrapped in craftsmanship and charm.
Portway Arundel Deluxe Multifuel Ecodesign Stove
The superbly engineered Arundel Deluxe Multifuel stove from Portway brings elegance and high-performance heating to your home. Its robust steel body houses the latest stove technology, which provides 82.5% efficiency and 5kW heat output.
You'll enjoy mesmerising views of the flames through the extra-large glass window. This Class A+ Ecodesign-compliant stove meets the highest emissions standards for clean, environmentally responsible warmth.
External air compatible for top-notch efficiency
Since it’s external air compatible, the Arundel can be installed with a direct external air supply, even in modern airtight homes. By removing the need to draw air from the room, the stove can easily reach its full 5kW output potential.
The Arundel's external air compatibility is perfect for today's well-insulated new builds. Enjoy the traditional charm of real stove heating with the latest technology for performance and efficiency.
Exceptional engineering for reliable warmth
Every Arundel Deluxe Multifuel stove features first-class engineering, from the robust steel body to the cast iron door and log retainer. Built to deliver lasting performance, it's the stylish centrepiece for comforting warmth in contemporary homes.
Westfire Uniq 37
The Westfire Uniq 37 wood-burning stove brings elegance and ample warmth to contemporary homes. With its 7.2kW heat output and sleek aesthetic, this Ecodesign-compliant stove is a real showstopper.
The contemporary body features stunning glass side and front panels for 180-degree flame viewing. This mesmerising focal point adds a touch of sophistication to any room.
External air compatibility for modern homes
The Uniq 37 is available as a CC (Closed Combustion) model, which uses external air for optimal performance in airtight modern homes.
Drawing combustion air directly from outdoors allows the stove to achieve its full 7.2kW heating potential. This makes the Uniq 37 CC the perfect solution for well-insulated new-build properties requiring an external air supply.
Complement your style with customisable options
The Westfire Uniq range offers versatile choices beyond the standard Uniq 37 model. Opt for a statement pedestal base, explore the extra-large Uniq 37 Large, or go for minimalist appeal with a wall-hung installation.
Whichever you choose, enjoy reliable DEFRA-approved warmth and eco-friendly performance that complements your unique style. The Uniq 37 brings sophistication to contemporary living.
Fire up your stove’s potential
Hopefully, you now have a clear idea of what an external air kit is, when it’s needed, and how it can transform your wood-burning stove’s performance. By supplying it with a direct flow of fresh, cool air from outside your home, your stove can reach optimal operating temperatures and burn cleaner and more efficiently.
External air kits are a modern must-have upgrade in any new-build home. They allow stoves to work their magic, not just gasp for air. Fitting is straightforward, and the kits have the right components and instructions.
Choosing a compatible stove and one of these nifty kits allows your stove to spend more time warming your socks and less time wheezing away in vain. Enjoy the brilliant blaze and heat your stove was built to provide.
Find an external air-compatible stove at Direct Stoves
Browse our wide range of external air-compatible stoves here to find the perfect option for your home. Plus, getting the right stove for you is a breeze with free delivery to the UK mainland, a range of finance options to suit every budget and no-hassle 14-day returns.
We're always here to help with any questions, too. Whether you want to know more about external air kits, need advice on choosing the right stove for your home, or would like assistance placing an order, we're just a phone call or an email away. Contact our friendly team on 0161 376 4191 or [email protected].
