Gas Fires by Flue Type

Gas fires can be broadly categorised according to the type of flue on which they can be installed. Here is a guide to help you identify the type of gas fire suitable for your property.

A Class 1 Chimney can be recognised by a traditional chimney stack topped by a chimney pot. Older brick chimneys are minimum 9" x 9" square, while newer properties often have a pumice or clay liner system with a minimum diameter of 7".

Class 2 Pre-Fabricated Flues can be identified by a metal flue and terminal protruding through the roof. Some terminate through a short rectangular pot (but with no chimney stack). The flue is usually 5" (127mm) in diameter.

Class 2 Pre-Cast Flues, sometimes called 'letterbox' flues, tend to have dimensions of 90mm x 183mm, terminating in a raised ridge terminal on the roof. These flues are very shallow in depth, so special slimline gas fires have been designed to suit.

Balanced Flue fires are designed for homes with no chimney. The fire has a glass front, with a concentric flue venting to an external wall, or in some cases up through a roof. Some Balanced Flue fires can be installed into Class 1 Chimneys using flexible liners.

Flueless gas fires require no flue at all. They work by using catalytic converters to safely filter the products of gas combustion. There are minimum recommended room sizes, and you will need a permanently open air vent into the room.

If you have no existing flue, are unable to accommodate a Balanced Flue system, and prefer not to have a Flueless gas fire, you may wish to consider our Electric Fires, which simply plug in to a standard electrical socket and require no flue at all.