Your property could have a flue box and a liner, a brick chimney and inglenook or maybe just a flat wall and no chimney at all. With all of these instances there are various options to install a gas fire. The main consideration when choosing a heating solution for your home is to decide if you will use an existing chimney or install a flue system. Using the existing chimney will give you the cheapest installation costs overall and will mean you spend most of your budget on the actual gas fire or fireplace. For each type of chimney or flue system there is a specific type of gas fire which can be installed. Whilst the pictures and information below may be of help to you, the only reliable way of establishing what chimney or flue type you have is to ask a gas safe engineer to visit and perform a survey. This should be done in all cases to check the compatibility of your chimney or flue with the type of gas fire you intend to purchase.


Why Use Gas?

Gas is the cheapest fuel to use per Kw of heat generated. Natural Gas is over 70% cheaper as a fuel than using electric, wood or bio-ethanol. By selecting one of our modern gas fire designs with a high energy efficiency rating you can dramatically reduce your utility bills. 



Class 1 Flue

A brick chimney is easily recognised by a chimney stack, with either a pot or gas terminal on your roof, which relies on the natural circulation of air through the room and up your chimney to expel the products of combustion. The minimum internal diameter will be 7” (or greater) and it may have had a real solid fuel fire in previously, especially in the case of older properties sometimes identifiable by an existing chair brick at the back of the fire opening. If you have a chimney (class 1 flue) you will be pleased to know that you will be able to have all types of chimney fires within our range. 

Pre Fabricated Flues (Class 1 & 2 Applications)

These are usually a metal interlocking single or twin wall flue pipe connected to a flue box, with a gas terminal on your roof. Creating the same circulation of air as a chimney. A flue pipe with a minimum internal diameter of 7” or more is recognised as a class 1 flue and a flue pipe of less than 7″ generally around 5” internal diameter is recognised as a class 2 flue. There are a large selection of gas fireplaces for class 1 & 2 applications available within our range, dependent on the size of flue and flue box you have in your property. 



Pre-Cast Flue (Class 2 Application)

Many new properties that do not have chimneys are fitted with Pre-cast flues. This flue is manufactured into rectangular hollow concrete or clay blocks that travel vertically, up through the cavity wall of your property, to a ridge vent or metal flue terminal on the roof. These flues tend to be very shallow in depth, although suitable deeper, appliances may be able to be installed with the use of either a spacer kit or deeper rebate on the fireplace. Choose from a wide range of smaller precast gas fires.


Power Flue (No Chimney Application)

A power flue fire is available for new homes built without a chimney or older properties where the flue is no longer of sound integrity. The fire has an electronically driven fan system on the outside of the wall to expel the flue gases and as such a sound is to be experienced when the fan is turned on. When the fire is not in use, some natural air circulation may occur through the flue terminal, which is quite normal. As the fire relies on a fan system customers can complain of noise if the fire is installed in a very quiet environment. This aside the fires provide a solution to installing a gas fire almost anywhere in a property.


Balanced Flue (No Chimney Application)

A balanced flue is a glass fronted gas fire, which is completely sealed from the room into which they are installed and vents directly to an outside wall. Air is drawn in from the outside for combustion purposes increasing its efficiency through an outer pipe whilst the inner pipe vents the combustion gases safely away to the outside of the property. These appliances have very high heat outputs and can be too over powered if installed in the wrong type of room. Most clients opt for a flueless gas fire with an open flame, higher efficiency and fraction of the cost. 




No Chimney in the Property?

Most modern properties are now being built without a chimney, mainly to save the cost of construction. If your home has no chimney there are 4 types of fire to consider installing.

Appliance Appliance Cost Running Costs Install Costs Positives Efficiency
Flueless Gas Fires Low Low Low Easy to Fit 100%
Balanced Flue Fires Mid to High Mid Mid to High High Power up to 85%
Chimney Gas Fires Low to High Low to High Low to High Many Designs up to 50%
HE Inset Fires Low Low Low Easy to Fit up to 85%
Bio Ethanol Fires Low High Low Easy to Fit 100%
Power Flue Gas Fires Mid to High Mid Mid to High High Power 90%
Electric Fires Low Mid Low Easy to Fit 100%

Flueless Gas Fires

These require no chimney or flue and are very easy to install and use. The benefits include low running costs, 100% Efficiency, 2.7Kw or 3.5Kw heat outputs, cheap to buy and install, CE approved and safe. Flueless gas fires can be installed on any wall within a room. Unlike all other flueless gas fires on the market our CVO flueless gas fire does not require catalytic filters or a glass screen. Flueless gas fires can be installed into most rooms (excluding bedrooms & bathrooms). There is a choice of wall mounted, traditional style or recessed into the wall fireplace versions in our range. 


Balanced Flue Gas Fires

Glass Fronted, >80% Efficiency and many sizes and heat outputs available. These fires require a “balanced flue” pipe system installing. This draws in fresh air from outside and exhausts through the same pipe. These fires should be used where 5Kw or more of heat is required.


Power Flue Gas Fires

Glass Fronted, >85% Efficient, these use a fan system to draw in fresh air and blow out the exhaust. The pipes are very small and can allow a fire to be installed almost anywhere as the pipes can even be run under the floor if required. The pipes are only 54mm or 80mm in diameter and can be routed up to 40m from the fire. These fires should be used where 5Kw or more of heat is required.


Bio Ethanol Fireplaces

These are fueled by liquid bio fuel. Due to the high running costs they should only be considered for mainly for decorative purposes and used for short periods at a time. Before considering a bio ethanol fireplace you should first check on the cost of installing a gas supply as installing a flueless gas fire will save a considerable amount of money for the same amount of heat.