Class 1 Chimney Gas Fires

Class 1 Chimneys vs Class 2 Chimneys

Class 1 chimneys are traditional, brick-built chimneys mostly found in older properties. These chimneys can handle a wide range of fuels, including wood, coal, and gas. Their main feature is the flue size—Class 1 chimneys have a larger flue than Class 2, around 7 inches (180mm) or more in diameter. This makes them suitable for most types of open fires and stoves. They offer excellent ventilation for smoke and gases.

In contrast, Class 2 chimneys are more modern and are often pre-fabricated, using metal or clay liners. They are designed for gas fires or electric fireplaces that do not generate much smoke. The flue size in a Class 2 chimney is around 5 inches (125mm) in diameter. This narrower design limits the type of appliances that can be connected, and often is not suitable for large open fires or stoves.

When buying a gas fireplace, it is important to know which chimney class you have to order a compatible fireplace. Choosing an unsuitable design for your chimney type can lead to poor heat output, inefficiency, and even be a safety hazard.

Please consult your registered gas fitter before making a purchase and if you need any help or further information, call us on 01274 850732.