Gas Fireplaces are more common than open solid fuel Fires in modern homes. Real open Fires than burn coal or logs, and require the homeowner to store vast amounts of fuel. Gas Fireplaces burn reusable artificial ceramic logs and look virtually identical to the real thing (open fires). Gas fireplace inserts have been created to simplify the process of installing a fire surround with a gas fire. The majority of large gas fire manufacturers such as valour, Flavel and wonder fire, will manufacture their entire range of inset gas fires to fit into a standard marble back panel opening size of 16.25 inches (413 mm) wide times 22.25 inches high (565 mm). This makes it incredibly simple to order a fire surround and purchase an inset gas fire from a variety of manufacturers. On occasion certain gas fires are designed to fit into an opening which is larger than standard, however this is not a problem as it is very simple to increase the cut-out size in the marble back panel.

Not all inset gas fires will be suitable for all chimney types

1. Certain inset gas fires are designed for class 1 (brick chimneys) only, and will not be compatible with a conventional precast flue or class to chimney. These radiant fires require the extra depth to generate a higher heat output, and for this reason are too deep to be installed into a shallow chimney or flue. 2. .Multi-flue gas fires are designed to be installed in class one, class two and precast chimney flues. These versatile fires will be flexible enough to be installed in all chimney types. Multi-flue gas fires are shallower than radiant convector class one fires, and for this reason have a smaller fuel bed (let's coal or pebbles), and also have a lower heat output. 3. Balance Flue gas fires are designed to be vented out of an exterior wall, and often require larger fireplace rebate. A fireplace rebate is the internal void within a fireplace to recess the fire. As balance flue gas fires will be installed against a flat exterior wall, the fire engine or mechanism needs to be recess within the fire surround (hence the need for larger rebate). 4. Flue-less gas fires work on a catalytic converter similar to a car, and also require larger fireplace rebate. These special fires do not require an exterior vent or chimney of any sort, however may require and air brick minimum size in order to function (please see specific details or owner’s manual).