Frequently Asked Questions

Click the sections below to see our range of FAQs.


What is HETAS?

HETAS (Heating Equipment Testing and Approvals Scheme) is the only specialist organisation approving biomass and solid fuel heating appliances, fuels and services. This also includes the registration of competent retailers, installers, servicing engineers and chimney sweeps.

How can I contact HETAS?

Email –

Call – 01684 278170 (option 2)
Lines open Monday to Thursday 8:30am to 5pm and Friday 8:30am to 4:30pm

Follow us on social media for regular updates and tips.

Before installation

Do I live in a smoke control area?

Your Local Authority is responsible for the designation and supervision of smoke control areas.
To find out if you live in a smoke control area, we recommend contacting your Local Authority to advise.
A guide to the rules of smoke control areas can be found here.

Can I install my stove myself and then get it approved?

It is a legal requirement to notify any solid fuel installation in England and Wales to the relevant Local Authority Building Control either via a Competent Person Scheme such as HETAS or directly to the council.

An application would need to be made to your Local Authority Building Control prior to installation if you intend to carry out the work yourself or if your installer is not registered with a Competent Person Scheme that covers the installation of solid fuel appliances. A HETAS registered installer can only notify work they have carried out themselves.

We strongly recommend the installation is carried out by a HETAS registered installer to ensure the installation is safe and complies with relevant Building Regulations.

Find HETAS registered installers through our postcode search.

How can I check I am using a HETAS registered installer?

Use our postcode or check business search here.

Call or email HETAS to check an installer is registered.

Look for the HETAS registered installer logo.

HETAS registered installer logo

How do I find an installer to work on a wet system?

Use the postcode search here. Ensure that only the boxes for ‘Stove with boiler’ and ‘Heating systems’ are ticked and this will bring up the competent installers for a wet system. You can also use the servicing search here and select ‘Service & Maintenance – Wet systems’ to bring up results for competent businesses.

Can any property have a stove?

Within reason, any property may be suitable whether there is an existing chimney or not. In most properties without an existing chimney, a system chimney may be installed as opposed to building a new masonry chimney. This may run within the property or externally providing it is safe to do so. It would be best practise to seek an appraisal from your local HETAS registered installer.

I have an existing wooden beam in my fireplace, is this okay?

Each appliance and chimney manufacturer specifies the safe distances from combustible materials in relation to the installation. Some manufacturers can supply additional heat shields to reduce distances for specific installations.

A survey of the proposed installation will give further clarity on whether the beam position is suitable or whether shielding or non-combustible alternatives can be specifically designed to look like the real thing. It would be best practise to seek an appraisal from your local HETAS registered installer.

Why is ventilation required and how is this calculated?

Ventilation is always required for the room in which the appliance is installed, details of which will be ascertained upon survey and installed discreetly in keeping with the building fabric. This ensures that there is an adequate supply of air for combustion, to prevent overheating and for the efficient operation of any flue. There are different ways of providing combustion ventilation so advice from a HETAS registered installer can help you to get the right installation for your needs.

After installation

What protection or support does HETAS offer after installation?

HETAS strives to promote and monitor continuous improvement in the safe installation and use of solid fuel appliances, systems, chimneys & flues, and their maintenance. As such, we are keen to be advised of any non-compliant installation carried out by a non-registered HETAS or registered HETAS engineer.

Email or call 01684 278170 (option 2)

Find more details regarding our complaints policy or our complaints questionnaire here.

What do I need before using my new installation?

You should ensure that your HETAS registered installer has provided the following before using your appliance:

Notice Plate

Carbon monoxide alarm

Manufacturer’s instructions

Either a paper copy Certificate of Compliance provided by your installer, or one sent to you by Royal Mail after your installer has notified the work through the HETAS Online Portal

I’m buying a property with a stove, what do I need to do?

Any solid fuel appliance fitted since April 2005 will require a document called a Certificate of Compliance. We recommend checking if the chimney has been swept and the appliance serviced. If not, have both done by a HETAS Approved servicing engineer and/or chimney sweep.

The Certificate of Compliance is normally provided by your solicitor, from the previous homeowner, during the purchasing/conveyancing process. If you have not received this document, please contact your solicitor, or contact

Find more information about Certificate of Compliance here.

I have not received my Certificate of Compliance.

From the completion of your installation, if your HETAS registered installer uses the HETAS Online Portal, your certificate should have arrived within 3 weeks via Royal Mail. If you have not yet received this, please contact our support team at or use this contact form.

If your HETAS registered installer uses paper certificates, this will be issued directly from them on completion of your installation.

Find more information about Certificate of Compliance here.

I need a replacement Certificate of Compliance.

Copies of HETAS certificates of compliance can be ordered through our online search. Simply enter your postcode and find the certificate for the property. Certificates cost £24 plus VAT and following payment you will receive an email with your certificate and an invoice.

Alternatively, you can contact our support team at or call 01684 278170 (option 2) and we will be happy to help.

How can I find out more information on the correct use of my appliance?

Always adhere to your manufacturer’s instructions. Every appliance is different and unique in its own needs and requirements to obtain the best and most efficient performance. Your HETAS registered installer should run through the correct use of your appliance once installed.

The following articles have useful information and tips:

Lighting a fire

Refuel your appliance safely

Safe disposal of stove ash

Slumbering your stove

How do I light a fire?

Refer to our useful guide to lighting a fire here.

We also have tips for refuelling safely and efficiently here.

When should I get my chimney swept?

We recommend you have your chimney swept at least twice a year when burning wood and at least once a year when burning smokeless fuels. The best times to have your chimney swept are just before the start of the heating season and after your stove has not been used for a prolonged period. If sweeping twice a year, the second time should be after the peak of the main heating season.

We recommend using our postcode finder for a HETAS Approved chimney sweep.

Consumer advice leaflets are available here.

I am concerned about the work my HETAS installer has carried out, what can I do?

In the first instance, if you feel able to do so we recommend raising your concerns directly with your installer. We understand and value your concerns so if you are unable to resolve this with your installer or need further support please contact our consumer complaints team. Email or call 01684 278170 (option 2)

Find more details regarding our complaints policy or our complaints questionnaire here.

Carbon monoxide (CO) alarm

Should a CO alarm have been fitted when my stove was installed?

The law in England and Wales states that new or replacement solid fuel installations in your home MUST have a carbon monoxide alarm fitted. The alarm must be permanently installed, be either mains or battery powered, and should incorporate a self-test and audible alert if the battery or detector cell develops a fault. The alarm must be fixed in the same room where the appliance is fitted and according to its instructions.

Test your carbon monoxide and smoke alarms regularly.

For more guidance and tips, take some time to view our series of video shorts, covering everything CO.

What should I do if my CO Alarm goes off unexpectedly?

In the case of your carbon monoxide alarm activating please follow the below instructions.

  1. Turn the appliance off.
  2. Open doors and windows to ventilate the building.
  3. Leave the building immediately and don’t return until your appliance or boiler has extinguished and the air in the room is clear.
  4. If you feel unwell go to your doctor, call NHS 111 or, if it is urgent phone 999 for an ambulance. Tell them you feel your symptoms may be related to carbon monoxide poisoning.
  5. Before you reuse the appliance, have it serviced and the chimney swept by a HETAS registered installer and/or a HETAS Approved chimney sweep.
  6. Do not use the appliance until you are told it is safe to do so.

Test your carbon monoxide and smoke alarms regularly. Also referred to as ‘Test it Tuesday’ – we advise you to test your carbon monoxide alarm at least once a month on a day you are likely to remember. Most carbon monoxide alarms have a simple button for you to press to test that your alarm is working.

For more guidance and tips, take some time to view our series of video shorts, covering everything CO.

I am redecorating my living room; can I move my CO alarm?

Yes, but do it when the appliance is not in use.

Please fix your alarm back in the same place your HETAS registered installer fixed it. This is to make sure that you are complying with Building Regulations.

To work safely, your carbon monoxide alarm should be in the same room as your appliance.

View our second CO video that looks at the appropriate positioning of a carbon monoxide alarm in accordance with the Building Regulations for solid fuel.

CO alarm positioning


Is it safe to purchase a new stove online?

There are many choices as with any appliance. Visit a HETAS Approved retailer to give you confidence in getting a suitable, efficient, and safe heating appliance for your home. All approved retailers have at least one HETAS trained showroom staff member, meaning quality advice.

When purchasing a product from a HETAS Approved retailer showroom:

You will have the confidence that there will be knowledgeable staff available in the showroom

Will purchase a safe and legal appliance with the appropriate amount of output needed to heat your home

Be able to identify key features of each appliance through a product labelling system to make an informed choice to suit your needs

Offer advice on the maintenance of your appliance

They may work with local HETAS registered installers that they have a good working relationship with, making your search for an installer easier

We recommend using our postcode finder for a HETAS Approved retailer.

What size does my stove need to be?

Your stove output is calculated dependant on the space to be heated. This along with other factors will indicate the size of the appliance required. Correct sizing leads to greater efficiency and more effective heating. We would always encourage this to be calculated and advised upon by a HETAS registered installer.

It would be best practise to seek an appraisal from your local HETAS registered installer, who will be able to carry out the necessary calculations to determine the size of the appliance required for the space.

How can I check if my appliance is HETAS Approved?

The HETAS product search will help you to find the appliance that is right for you. Our online search includes approved wood and multifuel stoves, cookers, biomass systems and chimney products.

To help maintain these standards, HETAS is the independent UK body recognised by the government for the testing and approval of solid fuel and biomass appliances and associated equipment and services.

Why choose a HETAS Approved appliance?

  1. Have confidence that the appliance conforms to the UK building regulations in its installation and use
  2. Have all relevant information on using the product in specified operating instructions for safe and effective use of the appliance
  3. It minimises the work installers must undertake to check that the products meet the relevant legal and best practice requirements

What is Ecodesign?

Ecodesign Regulations set new minimum seasonal efficiency and maximum emission requirements for solid fuel burning roomheater stoves, roomheater stoves with boilers and cooker appliances. Only those appliances that have been tested and verified as meeting these new limits will be able to be sold and installed legally within the UK. The emission limits include those for Particulate Matter (PM), Organic Gaseous Compounds (OGC), Carbon Monoxide (CO) and Nitrogen Oxides (NOx).

Read more detail on Ecodesign here.

Replacing open fires and upgrading older appliances with modern Ecodesign Compliant stoves could achieve significant emissions reductions – 90% for open fires and, depending on the age of the appliance, up to 80% for stoves.

How easy would it be to change the type of appliance – for example from gas to wood burner?

Any alterations to a fireplace which renders it capable of being used for a different fuel, for example from gas to solid fuel, is subject to Building Regulations.

It would be best practise to seek an appraisal from your local HETAS registered installer.


Do I need to line my chimney?

Whilst there is no regulation requiring every existing chimney to be lined, your installer must satisfy themselves that the chimney is free from defects and suitable for its intended use.

If work undertaken on the chimney, including installation of a new liner, is done in conjunction with the installation of a heating appliance, then that work is a controlled service and must be undertaken by a competent person or approved by your Local Authority Building Control.

Chimneys are lined for several safety reasons. New chimneys may require relining to suit the fuel type being used (a gas flue liner may not be suitable for other fuels). Chimney systems that predate 1965 will often require a modern lining solution.

We recommend contacting a local HETAS registered installer or HETAS Approved chimney sweep who will be able to advise you further.

Why do I need to replace or reline my chimney?

There will be one of three reasons why an existing chimney may need to be relined:

If it is found to be unsound from the results of an appropriate test by a skilled engineer

If the cross-sectional area of the flue is too large or small for the intended appliance

Any of the existing lining is found to be unsuitable for the proposed appliance type

When an appliance is replaced, Approved Document J states:

“if a chimney has been relined in the past using a metal lining system and the appliance is being replaced, the metal liner should also be replaced unless the metal liner can be proven to be recently installed and can be seen to be in good condition.”

Page 24, paragraph 1.39

Your HETAS registered installer or HETAS Approved chimney sweep can advise you on your next steps

What would be the best type of liner to use in my chimney?

Rebuilding or relining an existing chimney requires specialist advice. We strongly advise you to discuss your options during a visit from your local HETAS registered installer. If you decide to re-build a masonry chimney, this is work for a builder and may require planning permission and Building Regulations approval.

However, there is a wide choice of factory-made chimney relining systems that can be used. Fire-resistant precast concrete, clay and pumice flue liners or ceramic liners offer the most permanent solution, providing the existing chimney openings are big enough to take the correct size flue to suit the proposed appliance.

Double skin flexible stainless steel flue liners offer an alternative answer if the access is difficult or the existing chimney is unable to accept other types of liners. These flexible liners can be easier to install and replace but are not described as permanent. Significant periods of slow burning with solid fuels or infrequent chimney sweeping can give rise to corrosion damage. This can then reduce the expected life of the liner.

Insulated metal chimney systems offer a fast and convenient solution. They are robust and adaptable offering suitable solutions for many more challenging installations.

Contact your local HETAS registered installer to discuss your options further.


What fuel can I use with my new stove?

Make sure you select a fuel type that matches your appliance’s operating instructions and warranty for a long, reliable, and safe service.

If you live in a smoke control area you can only burn wood in a Defra exempt appliance. Alternatively, you can burn authorised fuels listed by Defra in a non-exempt appliance.

It is vital for you to determine whether you have (or want) a wood burning stove or a multi fuel stove. Wood burners have flat beds on which to lay wood log fuel, while multi fuel stoves have grates. You can put wood on a multi fuel stove, but you cannot effectively burn manufactured solid fuel on a wood burning stove.

It is preferable to burn hardwoods such as beech and ash, instead of softwoods like pine or fir. This is because hardwoods take longer to burn so you will use less fuel. Wet logs will tend to blacken the glass on your stove. Burning wet wood is also very inefficient as the fire must boil off the water in the wood before any heat is provided into your room.

From May 2021, wood sold in volumes of up to 2m³ in England will need to be Ready to Burn certified as having a moisture content of 20% or less. Suppliers selling larger quantities will need to provide customers with clear instructions on storing and seasoning so it is dry to burn.

To find out how dry your fuel is, and whether it is ready to use, you can use a moisture meter. You should expect to pay around £20 for a moisture meter. We do sell them if needed and you can contact us for more information.

Check the Woodsure website for your local Ready to Burn supplier.

Find more information on the Ready to Burn scheme here.

How do I find a Ready to Burn wood fuel supplier?

From May 2021, wood sold in volumes of up to 2m³ will need to be Ready to Burn certified as having a moisture content of 20% or less. Suppliers selling larger quantities will need to provide customers with clear instructions on storing and seasoning so it is dry to burn.

Check the Woodsure website for your local Ready to Burn supplier.

Find more information on the Ready to Burn scheme here.

Ready to Burn scheme mark

We’re here to help

Please do not hesitate to contact us if you have been unable to find an answer to your enquiry on our website and we will endeavour to help where we can.

Email –

Call – 01684 278170 (option 2)
Lines open Monday to Thursday 8:30am to 5pm and Friday 8:30am to 4:30pm

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