Installing a log burner in a garage conversion is an excellent option; carbon neutral, affordable and a standalone solution that can be perfect for detached garage conversions. But before rushing to buy your new stove it is important you understand what rules and regulations you need to comply with and how they may impact the choice of stove and design of your installation.

If you are researching heating solutions, be sure to read our garage conversion heating guide which covers alternative solutions and our overall recommendation of air con/heating. 

Smokeless Zones

Smokeless zones were introduced to improve the quality of the air we breathe, they restrict what fuels can be burned. It comes as a surprise to most people that wood is a restricted fuel and you can be fined £300 for burning wood if you live in a smoke control zone and use a non-exempt appliance.

Exempt Appliances – DEFRA Approved Stoves

A DEFRA approved stove has been tested and certified for use in smoke control areas and are our general recommendation when choosing a stove. A DEFRA smoke exempt appliance will ensure a minimum amount of air is supplied to the stove which enables efficient burning of the fuel minimising smoke and ensuring compliance with the Clean Air Act 1956.

In short, buy a DEFRA approved stove like the one below and you can’t go wrong!

Flue Options

The layout of your home, the existing roof design and location of your stove will influence the choice of flue. Typically, it is between a twin walled insulated flue and a traditional chimney which can be considerably more costly and involve planning permission.

Twin walled flues are the more popular option as they are cheaper, easier to install and suit most installations. We recommend you speak to a qualified HETAS engineer who will help you make an informed decision and provide an installation quote for your new stove.

Who are hetas?

HETAS operates an approved competent person scheme, similar to using a GAS SAFE engineer for your boiler installation. Log burning stoves are a solid fuel appliance and require adequate ventilation. They should be installed professionally and accompanied by a CO2 detector. Get a Quote from a HETAS registered professional here who can supply and fit a suitable stove. If you are supplying your own stove, make a note of the flue size which will be required by your installer.

Choosing a Stove

While most installers will offer a supply and fit service you may want to buy your own stove and opt for a installation only service. As we have already discussed we recommend a DEFRA compliant stove, but what else should you consider?

Heat Output - kW

The output of log burners are measured in kW, as most garages are of similar dimensions we can surmise the smallest stoves with an output of 4kW should be suitable. In fact, even a triple garage conversion with a heat demand of 13500 BTU/h would be sufficiently heated by a 4kW log burner.   

Hearth Size

This is an important factor to understand as it can add significant work and costs to the project. When browsing stoves, you will often see “suitable for 12mm hearth” listed as a selling point.

The hearth is the floor area beneath the stove and need to be able to withstand the heat. Stoves that can produce hearth temperatures in excess of 100 degrees require a constructional hearth. This involves your builder installing a non-combustible structure (large concrete slab) underneath the fireplace. The local building inspector will also need to approve the details of this installation which must be built to specific dimensions.

On the other hand, 12mm hearths are as the name suggests a 12mm covering. This is placed above the current finished floor to protect it from the new heat source. You will notice that stoves where the firebox is elevated off the floor are suitable for 12mm hearths, whereas low slung stoves will normally require a constructional hearth.


Installing a log burning in a garage conversion can be a great way to add warmth and character to the space. However, it's important to understand there are factors:

  • DEFRA Compliant
  • Flue Type
  • Hearth Size
  • KW Output

which constrain your choice and influence the difficulty and cost of the project. Hopefully you can now make a more informed decision and have a more constructive conversation with your chosen installer, building inspector and builder.

About the Author Michael NEGC

Michael is the Architectural Designer and Surveyor at North East Garage Conversions.
Michael has a HNC in Civil Engineering and a HND in Construction Management. Previous experience includes multiple renovations, a self build plus working as an Architectural Technician, Designer and Project Manager.

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