Roofing Superstore is proud to offer the latest range of chimney cowls, from popular brands such as Brewer Cowls, Colt Cowls, Windkat and more. All of the chimney cowls have been designed to resolve a number of common issues experienced with chimneys.

For any product recommendations or advice, don’t hesitate to call our team on 01752 692760 or use the live chat, they will be more than happy to help.

What is a chimney cowl?

Chimney cowls, also known as pot covers, come in a range of different styles and designs. Chimney cowls are fitted to the top of chimneys to solve a wide range of common issues, whilst also improving the performance of the chimney. They can be made from a range of materials, and include mesh structures, plastic caps and more complex metal structures.

Why use a chimney cowl?

There are a number of issues that can occur with the use of a chimney, and chimney cowls have been designed to specifically combat these issues, to create a clear, efficient and safe fire and flue system.

Birds and other animals

Firstly, the most commonly recognised issue is related to birds. A Chimney cowl creates a barrier to prevent birds and other animals from entering the chimney area, because birds often see a chimney as the perfect place to build a nest. Nests will then block the chimney, preventing air from being drawn properly, which reduces the efficiency of the fire. Another issue with birds nesting within a chimney is that their droppings, feathers and other mess can fall down into the fire, stove or wood burner. Additionally, birds can occasionally fall down the chimney, which can be relatively distressing for both the animal and anyone within the building.  

Prevent water ingress

Another issue that is resolved by the installation of a chimney cowl is the ingress of water into the flue system. In some circumstances, flue systems are sensitive to moisture and water, and long term issues can arise, such as rust and structural damage. Chimney cowls prevent the ingress of rainwater into the chimney, eliminating the possibility of serious issues caused by moisture.

Eliminate downdraught

A second and major benefit of installing a chimney cowl is to reduce or prevent downdraught. Downdraught is when air pressure from outside forces smoke back down the chimney and into the fire, wood burner or stove, causing bursts of smoke to enter the room, and preventing gases and smoke from exiting via the chimney. 

A chimney cowl will help to reduce or eliminate downdraught by stabilising air flow, and preventing exterior draughts and wind from forcing smoke back down the chimney.

Increase draw

Chimney cowls are also incredibly useful when looking to improve the draw of the fire. The draw of the fire is the air flow that flows into the fire, providing oxygen to the fire which is necessary in order to keep the fire ignited. Some fires have a poor draw, which means that they don’t ignite very well, and the hot air and smoke does not go up and out of the chimney. 

A chimney cowl improves the efficiency of the fire, the burn rate and the speed at which smoke and hot air is drawn up through and out the chimney. However, it is important to only use a chimney cowl that is specifically designed to increase draw on poorly performing fires, as if used on an already well-performing fire it can cause issues including overfiring. 

What different types of chimney cowl are available?

There are a number of different types of chimney cowl available, depending on the issue you are hoping to resolve. 

Birdguards

Birdguards are one of the most simple forms of chimney cowl available. They are typically mesh shaped, to prevent animals from entering the chimney space, whilst still allowing air to flow in and out of the chimney easily. There are a number of different birdguard chimney cowls available, depending on the type of chimney you have – choose from gas birdguards or solid fuel birdguards, or alternatively opt for a conetop birdguard or balloon birdguard, depending on the design you are looking for. 

Cappers

Cappers are another straightforward yet useful form of chimney cowl. Cappers are a single piece of material that caps straight over the chimney top to prevent water from entering the chimney space, avoiding any issues caused by long term moisture. Choose from traditional raincaps, which feature legs to rise the cap above the immediate entry point to the chimney, or more contemporary cappers which do not have the legs, resulting in a more subtle chimney cowl that cannot be seen.

H cowls

H Cowls are another popular form of chimney cowl. They have been designed to specifically combat the issue of downdraught, stabilising the draught and preventing smoke and potentially dangerous gases from being forced back into your home. In the shape of an H, it allows gases to escape by ensuring that downdraught cannot be forced straight down and into the chimney, it would instead have to pass around 90 degree bends.

Bonnet cowl

The Bonnet cowl, from Brewer, is a simple yet effective design of chimney cowl. The bonnet cowl consists of a simple curved piece of metal that is fixed above the chimney cowl, with gaps on either side to allow gases and smoke to escape, whilst preventing anything from entering the flue system.

Aspirotor cowl

The Aspirotor is a metal chimney cowl that has a contemporary and effective design. The stainless steel chimney cowl is designed to act like a turbine, with the wind catching the cowl and rotating it. This rotation increases the draw of air up the flue, which improves the fire efficiency. At the same time, the Aspirotor prevents any unwanted birds or animals from entering the flue system, and minimises the amount of water that can enter the chimney too. 

Aerodyne cowl

Another chimney cowl that helps to improve the draw up and out of the chimney, as well as eliminating downdraught, is the Aerodyne cowl from Brewer. This metal chimney cowl comes in range of different colours, but has a unique venturi shape, which draws air into the chimney cowl. When this air is drawn in, the unique shape causes a drop in air pressure, drawing air up from the stove into the atmosphere. 

Spark arrestor cowls

Spark arrestor cowls are a form of chimney cowl that have been designed to reduce and eliminate the emission of sparks from the chimney, which could cause damage and ignite fires. Spark arrestor chimney cowls are particularly beneficial on thatched roofs, where a small spark could ignite the whole roof, causing serious damage.

Windkat chimney cowls

Windkat chimney cowls are often considered the market leading product that combines a chimney pot and chimney cowl. An eye catching yet functional design, the Windkat chimney cowls create the perfect solution that does not rely on the wind to draw air, but instead creates a constant draw to provide an efficient and steady fire. Additionally, the Windkat chimney cowl stops downdraught, ensuring your home is safe and free from smoke and dangerous gases. 

There are a number of other chimney cowls available, including Stealth cowls, the Windmaster, and lobster back chimney cowls.  

What sizes are chimney cowls available in?

Chimney cowls are available in a range of sizes, so it is important to get the correct size for your chimney. Standard sizes range from 100mm to 300mm – this is the internal diameter measurement. Alternatively, Brewer Cowls offer a bespoke chimney cowl service, whereby you can order bespoke sizes through Roofing Superstore to ensure you have the perfect fit. Just give our team a call on 01752 692760 or use the live chat to discuss this further.

How do you fit a chimney cowl?

Fitting a chimney cowl is incredibly simple, the cowl simply needs to be strapped, bolted of fitted with a sleeve over the chimney. Fixing a chimney cowl is something that does not damage the chimney, meaning they can be removed and replaced as necessary, without leaving any marks or holes. Almost all chimney cowls are available with the strapping method of fixing as this is considered the most straightforward and secure fixing method.