What size stove?

The heat output of a stove is measured in Kilowatts (kW).
The size of your wood-burning stove depends on the size of the area you wish to heat.
A stove that is too large can cause just as many problems as a stove that is too small, as if it is too big for the room, you will be forever cutting the air supply to keep the room temperature down. As a result, combustion will be incomplete and soot will quickly build up on the stove window and in the chimney. In addition, the quantity of soot particles you emit into the environment will be disproportionately high.
A draughty Victorian house clearly needs more heating power than a well insulated, double glazed modern house. For the former, a calculation based on 1kW of heat per 10 cubic metres of space would allow for contingent heat loss while for the highly insulated modern new build might require as little as 1kW of heat per 25 cubic metres of space.

Stove KW size calculator:

The following formula will help you calculate the size stove needed to adequately heat your room. Please remember that the number of doors and windows etc. in a room will have a marginal effect, so always over rather than under estimate.
Our initial free survey will accurately identify the right sized stove for you, however, the following formula provides a rough guide to help you estimate the size stove needed to adequately heat your room to a comfortable room temperature.
For s comfortable room temperature of around 21°C when the outside temperature is 0°, you will need 1kW of heat for every 14 cubic metres of space in a typical 1930's house with cavity wall insulation, double glazing and loft insulation..
First calculate the cubic area of the room you are looking to heat, (multiply the length, the width and the height of the room), and then then divide this figure by 14 as 1kW of heat is need per 14 cubic metres of space
(Length in metres x width in metres x height in metres) ÷ 14 = kW

If you do not have double glazed windows in the room then add 1kW for each window. If you have radiators in the room that you plan to keep running minus 1kW for each radiator.

Should I choose a steel or a cast iron stove?

Cast iron is the traditional material used to manufacture a stove. Cast iron stoves take a longer time to heat up and hold their heat, so giving a high heat output for a longer time. The most controllable stoves are often cast iron.
Steel stoves often heat up quickly to give prompt heat to a room and because steel bodied stoves are typically more airtight, they offer more sensitive burn speed control. The door seal is sometimes not as tight as a cast iron stove, but due to the elastic nature of steel it is very durable and resistant to damage.

Radiant or convection stove?

There are two different types of stove: radiant stoves and convection stoves.
The radiant stove concentrates the heat around the stove itself, while the convection stove distributes the heat out into the whole room.
The type you choose will therefore greatly depend on what you want your stove for. If you want to be warm and cozy, close to the stove; the radiant is a good choice.
If, on the other hand, the stove is also to play an effective role in heating your home as a primary heat source, you should choose a convection model.

What is Airwash?

Airwash is a design feature that uses a specially placed vent or vents to draw in air to be directed down the glass surface on the inside of the front door. This helps to keep the soot and creosote from building up on the glass so keeping it cleaner for longer, allowing you to enjoy the glow and flames to the full.

What is the difference between a woodburning and a multi-fuel stove?

Wood burns best on a bed of ash so woodburning stoves usually have a flat bed on which to build the fire and no ashpan, with air for combustion coming from above.
A multi-fuel model gives you the option of burning solid mineral fuels (coal etc) too. They have a "riddling" (raised) grate, as smokeless coal requires combustion air from underneath the fire, and an ashpan to collect the cinders but also have airwash so that they can also effectively burn wood. The riddling grate allows the ash and cinders from smokeless fuels, anthracite or peat/turf briquettes to be riddled into an ashpan below, maintaining the primary airflow through the fuel bed and, hence, creating the optimum conditions for efficient combustion of those particular fuels.

What are the benefits of a multi-fuel stove?

A multi-fuel stove will burn a variety of different fuels. Recommended fuels include smokeless fuel, wood and peat.
Please bear in mind that wood will normally burn better on a wood burning stove.

A multi-fuel stove is significantly more efficient than an open fire.

The best fuel to use is Smokeless coal, and is specified by stove manufacturers. Petroleum based industrial fuels should always be avoided.

What are the benefits of a wood stove?

A wood stove will burn seasoned hardwood in the most effective manner. It will combine long burn times with the least amount of ash.

A wood stove is significantly more efficient than an open fire. Stoves can run at an 85% efficiency compared to just 20% with an open fire, where over four fifths of the heat is lost up the chimney.

The best fuel to use is seasoned hardwood. For the best results this means dry wood with a moisture content below 20% that is well, but not too tightly, packed into the firebox. The more moisture there is in the wood, the more it will smoke and possibly cause tar to build up in the chimney. Not only that but it will produce less heat. Peat can be burned in turf or brick form, but the moisture content must be low. Household refuse will burn successfully but only if it is dry and fairly tightly packed. Never burn plastics.

Can I burn wood in a multi-fuel stove?

Yes, it is fine to also burn logs in a multi-fuel appliance, but be aware that the presence of a grate and ashpan often reduces the firebox area, meaning less room for your logs. If you are sure that you will only ever burn logs, it is best to go for a dedicated woodburning appliance. Some appliances can be converted to multi-fuel in the future should your circumstances change.

Can I burn house coal in a multi-fuel stove?

No. You can only burn anthracite, or manufactured smokeless fuels certified as suitable for use in a closed heating appliance. Ordinary house coal contains volatiles which can seriously damage your appliance and flue. Burning bituminous coal, 'petro-coke', or any other petroleum-based fuel will invalidate your product's warranty.

How much ash should be left in the wood burning stove?

Keep a 2-3 cm thick layer of insulating ash. The ash layer insulates the bottom of the stove in the same way as the fire bricks or vermiculite board on the sides of the stove. This ensures a high combustion temperature which contributes to a cleaner more efficient burn.
Furthermore, the ash layer protects the riddling grate against premature failure and increasing its life expectancy. Empty the ashpan as required. Store any hot ashes in a suitable ash bucket until all embers are fully extinguished. Cold ash can then be disposed of on the garden compost or with the rest of your household waste.

Will a stove reduce my energy bill?

As the price of gas and ity continue to rise exponentially, the commercial case for stoves becomes stronger. As a rough rule of thumb, a fully integrated Biomass boiler and central heating system would save you between £100 and £150 per annum on your heating bills when compared to a modern gas boiler system.

If you are using ity or oil to heat your home the financial savings are even more significant with potential savings of upwards of £500 per year if you are replacing central heating.

As stoves and Biomass boilers have a 20 year lifespan they offer an excellent and extended return on your investment when compared to the 5-7 year lifespan of a typical gas system.

Can I heat my whole house using a stove?

Although often installed as standalone features to heat one or more rooms, many larger wood and multi-fuel stoves can be connected to a back boiler that heats domestic water. They can also be connected to radiators to provide central heating.
A wood burner with a top, back or wrap around boiler can heat from 4 to 12 radiators and some hot water. You can also fully integrating combi boilers with wood burning boilers but installation must be carried out by a HETAS registered engineer.
Underfloor air ducting can also be installed to provide ambient heating through heat convection.

How efficent are wood / multifuel stoves?

Fireplace and stove technology has come a long way in recent years. Modern stoves are designed to maximise effective combustion and can be very efficient.

All stoves on sale in the UK should include an efficiency percentage in line with British and European standards, representing the proportion of energy in a fuel transferred to heating the room.

The Solid Fuel Technology Institute publishes a register of more than 3,000 solid fuel appliances, including their efficiency percentage ratings.

How much do stoves cost to run?

There are significant localised cost variations in the price of wood, however, based on a well insulated 3 bed semi-detached house, the fuel cost of running a wood-burning system for central heating and hot water is typically between £450 and £700 a year.

Multi-fuel stove running cost vary according to the type and price of fuel used.

Our advisors can provide detailed site specific operational cost projections to help you choose the optimum way to heat you home.

Do I need a chimney to install a solid wood fuel stove?

If you don't have an existing chimney, twin wall insulated flues can be fitted to safely convey heat and smoke away from the appliance.

Planning permission and Conservation Area Consent may be required if the property is listed or located in Conservation Area.

Which types of chimneys are suitable for stoves?

One of the most important pre-conditions for an efficient stove is the chimney. In principle, the chimney functions as the "engine" of the wood-burning stove. If the installation does not produce the correct draught, it will not function as it should. New stoves place higher demands on draught and chimney conditions than older stoves using traditional combustion principles. The stove can be installed on a brick or fabricated chimney system.

Approvals and Standards:

CE approval and EN Standards

The CE mark is a key indicator of a product's compliance with EU legislation. By affixing the CE marking on a product, a manufacturer is declaring, on his sole responsibility, conformity with all of the legal requirements to achieve CE marking. It is not a guarantee of quality; it is not a quality mark, it does not imply any form of official approval as it is not issued by any official body and there is no such thing as an official 'CE Certificate' - rather, it is a way of providing definitive information about a product so that the specifier can make an informed choice. As different countries may have different standards for, say, efficiency, or fire-resistance or smoke emission, this means that they may choose to prohibit certain products even if they have met the minimum requirements laid down in the EN Standard. For instance, the UK applies a different smoke emission standard while Germany applies a higher efficiency standard.
Currently all stoves imported into the UK require CE approval to ensure that they conform to European safety and efficiency standards – EN 13240 for freestanding stoves and EN 13229 for inset stoves.
The improper application of a CE Mark, or an improper claim of conformity to EN Standards can constitute a criminal offence of deception, which in the UK can carry a penalty of up to 10 years imprisonment + an unlimited fine + confiscation of property + debarment from serving as a company director.

Defra approved Stoves and Authorised Smokeless Fuels

DEFRA is the UK Government Department of the Environment, Food and Rural Affairs which regulates smoke emissions under the Clean Air Act 1993.
The Clean Air Act 1993 prohibits emissions of smoke within smoke control areas, unless using an exempted appliance or using an authorised smokeless fuel i.e. fuels that have passed tests to confirm that they are capable of burning in an open fireplace without producing smoke. The Clean Air Act prohibits emissions of dark smoke from any chimney.

For a list of Smoke Control Areas visit control areas

Defra approved or "exempted" wood burners and stoves have passed tests to confirm that they are capable of burning an unauthorised or inherently smoky solid fuel without emitting smoke.

For a list of Exempt Appliances (Approved for use within an Smoke Control Area) visit - England

DEFRA approved or "smokeless" fuels can burn on an open fire without producing smoke.

For a list of Authorised Fuels visit Fuels - England

What does HETAS approved mean?

HETAS is the independent UK body recognised by Department for Environment, Food and Rural Affairs (DEFRA) for the official testing and approval of domestic solid fuels, solid fuel burning appliances and associated equipment and services.

The list has been prepared by HETAS at the invitation of DEFRA for the guidance of local authorities and others concerned with the choice of solid fuel appliances.

The HETAS approved product logo gives reassurance to the installer and end user that the appliance they are going to buy complies fully with current energy efficiency and safety requirements. To an installer, using a HETAS approved product saves them a significant amount of time as they know the product is suitable for use. Without the appliance being HETAS approved the installer would need to check the products test reports and ensure installation and user instructions give the correct advice.

For further information visit the HETAS website.

I do not have an exempt appliance and live in a Smoke Control Area

If you do not have an DEFRA approved / exempt appliance and live in a Smoke Control Area you can continue to use the unauthorised appliance but only if using an authorised smokeless fuel. To know what fuel can be burned in an exempt appliance, look at the manufacturer's instructions.

For a list of Authorised Fuels for use in England visit DEFRA


Inset and Outset Fires

There are four main styles of fire,
Inset (to go into a fireplace, to sit inside the fireplace opening behind the hearth)
Outset (sit on the hearth outside the fireplace opening, or wall hung without a surround)
Hang On The Wall (can usually be installed without a hearth)
Hole In The Wall (can be installed without a hearth

Glass Fronted and Open Fronted Fires

There are two main types of fire - glass fronted and open fronted. The glass fronted fires offer slightly better efficiencies than an open fronted gas fire, however, in recent years this gap has tightened, but the glass front does detract from the effect of the fire and will need cleaning on a fairly regular basis to keep the viewing area clear. The open fronted fires are less efficient but generally the effect looks more realistic.

Radiant or Convector Fire

There are two main ways the fire can get the heat into your room, one is a convector the other radiant. Convector draws cool air in underneath and puts hot air out through the top of the fire, using the basic principal that heat rises.
A radiant fire relies on the ceramics in the fire bed and the hot box lined with ceramic fibre to radiate the heat into the room.
The only thing that matters in the choice of your fire is the output of the fire rather that the way it gets the heat into your room.

Electric Fires

If you decide on an electric fire you can choose from wall mounted or inset depending on its suitability to your property. The wall mounted ones will suit most situations and all you require is a normal plug socket.

The inset electric fire will require building work to make an opening for the fire to inset into. This can be done into a standard cavity wall, a chimney breast or suitably rebated mantle piece.

An electric fire is 100% efficient but will have much higher running costs than gas fires, electric fires. They are ideal if you want a warming effect and an occasional boost of heat as they usually have a 2 kilowatt output but are not suitable for a main source of heat for a room; in most cases they are used as a backup to central heating.

Gas Fires

Although gas fires are now a lot more efficient, and have much higher outputs than before, in most cases they will not be suitable as a main source of heat for a room, in really cold conditions other forms of heat may be required i.e. central heating.

I have no chimney. Can I have gas fire?

Yes if the gas fire is being fitted on an exterior then a balanced flued gas fire or power flued gas fire could be installed, also a flue less gas fire could be installed or a new insulated flue system for a conventionally flued gas fire could be installed inside or outside the property.

Does my gas fire require an air vent?

Most flueless gas fires require a 100 square cm air vent and any conventionally flued gas fire with a rated input (not output) of 7kw generally requires 100 square cm air vents.

Can I have a remote control for my fire?

A lot of gas fires come with a remote control system as standard now.

Can you have gas fires made to measure?

Yes we can have gas fires made to many shapes and sizes.

Does a Gas Safe engineer need to install my gas fire and can you provide this service?

The Building Regulations in England and Wales make it a legal requirement for the appropriate Local Authority (LA) to be informed about the installation of a heat producing gas appliance e.g. boiler or fire. Only a Gas Safe registered engineer can fit a new gas appliance. Once a gas appliance has been installed it can only be notified by a Gas Safe registered engineer.


Does my chimney need to be lined?

A flue liner is advisable but not mandatory and you may well have been offered differing advice on chimney lining. It is important to note that stoves have different operational requirements for the open fires for which most UK chimneys were designed. Because stoves are more efficient, less heat is transferred to the top of the chimney. It is this heat that, in an open fire, contributes to the ‘draw’ on the chimney pulling the smoke out.

A reduced draw can have a number of potentially catastrophic impacts on your stove. While blacked glass and occasional smoke backdraughts may be a minor inconvenience, the fire risk associated with tar accumulation in a low draw chimney and the significant risk of a lethal carbon monoxide backflow caused by a ‘cold plug’ at the top of the chimney are why all manufacturers and accredited installers will recommend that the flue serving a stove, (multi-fuel or wood burning), should be lined.
An unlined chimney may also affect you house insurance.

Do I need a cowl?

It is good practice to fit at least a rain cap. When you are not using the stove and it is raining you are more likely to collect rainwater in the stove body if you do not have a cowl.

Brick Built Chimney

The classic brick built chimney is suitable for all gas and electric fires and stoves. As these chimneys are deep you can choose a full depth gas fire through to the shallower slimline or electric products.

Flues and Fires

Pre-Fabricated Flue

Pre-fabricated chimneys are suitable for most gas and electric fires and gas stoves. Pre-fabricated chimneys offer a good depth so you can choose from the majority of full depth gas fires and all slimline gas and electric fires.

Pre-Cast Flue

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.

Power Flue

A power flue is an open fronted gas appliance with an electronically driven fan system either semi recessed or surface mounted 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.

There are two types of power flue options available, a rear flue or side flue for left and right applications in instances where it is not possible to rear flue through the chosen wall (conditions apply). It may also be possible to install a deep power flue gas fire for added realism, subject to the depth of rebate on a surround if applicable or if installed with a spacer kit where available.

Balanced Flue

Balanced flue fires are glass fronted and available as both inset and outset models. They are completely sealed from the room into which they are installed and vents directly to an outside wall. Air is drawn in through the outer pipe, and combustion gases are expelled through the inner pipe. Balanced flue fires do not require an electricity supply, or a chimney.

Flueless fires

A relatively recent innovation, flueless fires don't require a chimney as they use a catalytic converter to remove fumes. The great thing is that none of the heat is lost up a chimney, so they are 100 per cent energy efficient and only use 25 per cent of the gas consumed by other decorative models. Flueless fires require a minimum room size and additional ventilation into the room.
All alterations and fittings can be carried out by Coeval Fires. Please contact us for a free site consultation.

We welcome enquiries for checking you have the correct flue type for your product.

Green Heating:

Carbon neutral energy

Fireplace and stove technology has come a long way in recent years. Spiralling energy prices, a step change in stove combustion efficiency and the increasing availability of sustainable, carbon neutral Biofuels have made stoves an elegant, environmentally friendly and cost effective way to heat your home. But why stop there? The latest stoves are not only an attractive way to provide ambient area heating, they can also heat your water or run your home central heating

What is biomass?

Biomass is biological material derived from living, or recently living organisms. In the context of biomass for energy this is often used to mean plant based material, but biomass can equally apply to both animal and vegetable derived material. It doesn't include fossil fuels.
The CO2 released when energy is generated from biomass is balanced by that absorbed during the fuel's production.
This is why it is considered to be a carbon neutral process. For small-scale domestic applications of biomass the fuel usually takes the form of wood pellets, wood chips and wood logs.
For more information on green heating see our Green Heating page

Carbon neutral biofuels

Biomass is organic matter of recent origin. It doesn't include fossil fuels.
The CO2 released when energy is generated from biomass is balanced by the C02 absorbed during the fuel's production making neutral it a carbon neutral process.

For small-scale domestic applications of biomass the fuel usually takes the form of wood pellets, wood chips and wood logs.

Stove efficiency

Good quality modern stoves are designed to maximise effective combustion and are about 80% efficient.
Biomass boiler systems operate at 95%-100% efficiency.

Stand alone central heating systems

Higher output wood and multi-fuel stoves can be connected to a back boiler that heats domestic water.
They can also be connected to radiators to provide central heating. A wood burner with a top, back or wrap around boiler can heat from 4 to 12 radiators and some hot water.
Underfloor air ducting can also be installed to provide ambient heating through heat convection

Integrated central heating systems

Fully integrating combi boilers and wood burning boilers systems are a flexible and efficient way of heating your home but installation must be carried out by a qualified HETAS registered engineer.

Biomass boiler systems

Wood-fuelled heating systems, also called biomass systems, burn wood pellets, chips or logs to to provide warmth in a single room or to power central heating and hot water boilers.
Modern wood burning boilers and stoves are clean, super-efficient, often computer controlled and comparable to high efficiency oil condensing boilers.
Once the biomass heating system is switched on everything runs automatically so no user intervention is needed, even cleaning of the heat exchanger and ash removal on some models is fully automated.

If you have any further questions please don't hesitate to call or email us for further information.

What is solid fuel

Solid fuel refers to various types of solid material that are used as fuel to produce energy and provide heating, usually released through combustion. Solid fuels include wood, charcoal, peat, coal, Hexamine fuel tablets, and pellets made from wood, corn, wheat, rye and other grains.