Regulation 30 of the Gas Safety (Installation and Use) Regulations 1998 restricts where gas appliances can be installed, so that in a bathroom or shower room only a room-sealed appliance may be fitted, and bedrooms face further limits depending on the appliance type and heat input.

What “room-sealed” means

Approved Document J defines a room-sealed appliance as one whose combustion system is sealed from the room in which the appliance is located, and which takes its combustion air from a ventilated uninhabited space in the building or directly from the open air, and vents its combustion products directly to the open air outside. A balanced flue appliance is described as a type of room-sealed appliance that draws its combustion air from a point outside adjacent to where the products are discharged, most commonly through an external wall.

Regulation 30: bathrooms and shower rooms

Regulation 30(1) of the Gas Safety (Installation and Use) Regulations 1998, which the legislation marks as applying in England, Wales and Scotland, says no person shall install a gas appliance in a room used or intended to be used as a bathroom or shower room unless it is a room-sealed appliance. That applies to boilers and any other gas appliance. It is a rule about installation, and it does not turn on the size of the appliance.

Regulation 30: rooms used for sleeping

Regulation 30(2) says no person shall install a gas fire, other gas space heater or a gas water heater of more than 14 kilowatts gross heat input in a room used or intended to be used as sleeping accommodation unless it is room-sealed. Under regulation 30(3), a gas fire, other space heater or gas water heater of 14 kilowatts gross heat input or less, and any instantaneous water heater, may be installed in such a room only if it is room-sealed or incorporates a safety control designed to shut the appliance down before a dangerous quantity of combustion products builds up in the room.

Cupboards, compartments and adjacent spaces

Regulation 30(4) extends these restrictions to a cupboard or compartment within the room concerned, and to a cupboard, compartment or space adjacent to the room if there is an air vent from that space into the room. The Approved Document J summary of the regulations makes the same point, so a boiler tucked into an airing cupboard connected to a bedroom or bathroom by a vent needs to satisfy the same test.

Older bedrooms and conversions

The Health and Safety Executive says that since 31 October 1998 any room converted to sleeping accommodation should not contain an over-14kW gas fire, space heater or water heater, including a gas boiler, unless it is room-sealed, or one of 14kW or less, or an instantaneous water heater, unless it is room-sealed or has an atmosphere-sensing device. If a room containing such an appliance was already used as a bedroom before 1998, HSE says a risk assessment is needed to decide whether it can still be used, and a Gas Safe registered engineer should be asked to check any appliance of doubtful safety.

The Approved Document J summary of the Gas Safety Regulations adds that when any gas appliance is installed, checks are required to ensure compliance, including the effectiveness of the flue, the supply of combustion air, the operating pressure or heat input and the operation of the appliance, and that any flue must be installed in a safe position and be adequate, suitable and effective for the appliance it serves.

Practical points before booking work

When getting a boiler quote, the location of the proposed boiler should be stated so that the installer can confirm it meets these rules. The HSE also strongly recommends carbon monoxide alarms as a precaution but stresses that they are not a replacement for regular maintenance and safety checks by a Gas Safe registered engineer. Approved Document J separately says a carbon monoxide alarm should be provided in the room of a new or replacement fixed gas appliance in England.

FAQs

Can a combi boiler go in a bathroom?

Only if it is a room-sealed appliance, according to regulation 30(1) of the Gas Safety (Installation and Use) Regulations 1998.

Does the rule cover an airing cupboard next to a bedroom?

Regulation 30(4) covers a cupboard or space adjacent to the room if there is an air vent from it into the room.

Do these rules apply in Northern Ireland?

The legislation marks regulation 30 as applying in England, Wales and Scotland. Northern Ireland has its own gas safety regulations, which are not covered here.

Bottom line

The room-sealed rule restricts where gas boilers and heaters can be placed: always room-sealed in bathrooms and shower rooms, and subject to size and safety-control conditions in rooms used for sleeping, including linked cupboards. Check the location and appliance type with a Gas Safe registered engineer before work begins. This is general information for Great Britain, not advice on a specific installation.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• legislation.gov.uk, “The Gas Safety (Installation and Use) Regulations 1998, regulation 30: Installation of gas appliances”
• Health and Safety Executive, “Gas safety – Home owners”
• Ministry of Housing, Communities & Local Government via GOV.UK, “Approved Document J: Combustion appliances and fuel storage systems” (PDF, 2022 amendments)

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.

Approved Document J says flue outlets should be situated externally so that combustion products disperse and, for balanced flues, air can be drawn in, and it sets out minimum separation distances from openings, gutters, corners, boundaries and other terminals for gas appliances.

What the guidance requires

Approved Document J, published on GOV.UK for use in England, says at paragraph 3.23 that outlets from flues should be situated externally so as to allow the dispersal of products of combustion and, if a balanced flue, the intake of air. The document shows a way of meeting this by locating outlets as shown in Diagram 34 and Diagram 35, with a table of minimum separation distances for gas appliances of up to 70kW net input. A further diagram, Diagram 35, covers outlets near roof windows. The guidance concerns building work in England, and nothing in it removes the separate duty under the Gas Safety Regulations that flues be installed in a safe position.

The separation table

The table gives minimum distances, in millimetres, for terminals in a range of locations: below and above an opening, horizontally to an opening, below gutters, soil pipes and drainpipes, below eaves, below a balcony or car port roof, from a corner or boundary alongside the terminal, from a surface or boundary facing the terminal, from another terminal, and above ground, roof or balcony level. The distances depend on whether the flue is balanced or open, whether it is natural draught or fanned, and, for some locations, the appliance’s rated heat input.

Notes to the table explain that an “opening” means an openable element such as a window or a fixed opening such as an air vent, and that smaller separations to a boundary may be acceptable for appliances shown to operate safely with such separations from adjacent or opposite surfaces. Because the figures vary so much with the type of flue, the installer should confirm the applicable distances for the particular appliance against the table and the manufacturer’s instructions.

Terminals and guards

The guidance says flue outlets should be protected where there is significant risk of blockage. Flues serving natural draught open-flued appliances should be fitted with outlet terminals if the flue diameter is no greater than 170mm, and larger flues should be assessed for blockage risk locally; in areas with nesting squirrels or jackdaws a protective cage of specified mesh size may be acceptable. It also says an outlet should be guarded if people could touch it or it could be damaged, and that an outlet in a vulnerable position, such as within reach from the ground or near a balcony, veranda or window, should be designed to prevent entry of anything that could obstruct the flow of flue gases.

Condensing boiler plumes

A note in Approved Document J says that the wet plume from a condensing boiler, positioned according to the safety distances in Diagram 34, can sometimes be a nuisance to neighbours. It states that the nuisance is not within the scope of the Building Regulations but that such installations could be considered a statutory nuisance under the Environmental Protection Act, and suggests installers may adopt the guidance in Chapter 6 of the Guide to Condensing Boiler Installation Assessment Procedure for Dwellings. It also recommends care to locate outlets away from parts of the building that could be damaged by frequent wetting.

Elsewhere the guidance says combustible materials in the building fabric should be protected from heat dissipating from flues, and that a fluepipe or chimney passing through a fire compartment wall or floor must not breach the fire separation requirements of Part B.

If a neighbour builds nearby

The Health and Safety Executive says the Gas Safety (Installation and Use) Regulations 1998 and the Building Regulations require flues to be installed in a safe position at specified distances from the boundary, but that some installations may not comply and still operate safely. It suggests that neighbours, builders and householders consult one another before an extension starts, and that anyone still concerned should ask a Gas Safe registered engineer to examine the flue. Planning permission for an external flue is a separate matter, covered in another guide on this site.

FAQs

Are the distances the same for every boiler?

No. The table in Approved Document J varies by location, flue type, draught type and, for some locations, appliance rating.

Can a neighbour’s extension affect my boiler flue?

HSE says an extension might affect the safety of a flue’s position and advises consultation before work starts and an examination by a Gas Safe registered engineer if concerns remain.

Is a condensing plume covered by the Building Regulations?

Not according to Approved Document J, which says any nuisance is outside their scope but could be a statutory nuisance under the Environmental Protection Act.

Bottom line

A boiler flue outlet must be placed so that combustion products disperse safely, kept clear of openings and boundaries by the applicable distances and protected against blockage and contact. Plume nuisance and neighbours’ building work are separate concerns that are best raised early with the installer or a Gas Safe registered engineer. This is general information for England, not advice on a specific installation.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• Ministry of Housing, Communities & Local Government via GOV.UK, “Approved Document J: Combustion appliances and fuel storage systems” (PDF, 2022 amendments)
• GOV.UK, “Combustion appliances and fuel storage systems: Approved Document J”
• Health and Safety Executive, “Gas safety – Home owners”

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.

The Gas Industry Unsafe Situations Procedure (GIUSP) tells Gas Safe registered engineers how to deal with unsafe gas installations, and it uses two categories, Immediately Dangerous and At Risk, that determine whether an appliance must be disconnected and who is responsible for it being repaired.

What GIUSP is

According to Gas Safe Register’s April 2024 factsheet, the Gas Industry Unsafe Situations Procedure is guidance available to all gas engineers, designed to protect householders from unsafe gas appliances, chimneys, flues and pipework. It assists engineers in complying with gas safety law, including the Gas Safety (Installation and Use) Regulations 1998, and applies to installations fuelled by different types of gas, in homes and businesses. The legislation marks the 1998 Regulations as extending to England, Wales and Scotland, so this guide describes Great Britain; Northern Ireland has separate gas safety regulations that are not covered here.

The factsheet says that when an engineer identifies an unsafe situation they should explain what the fault is and try to find the cause and repair it. Where that is not possible, they should tell the householder that the fault must be repaired before the installation is used again. If it cannot be corrected immediately, the engineer should make the installation safe, after first seeking the householder’s permission, which is normally done by disconnecting it or turning off the gas to the affected part, depending on how serious the defects are.

Immediately Dangerous

The factsheet defines an immediately dangerous installation as one that, if operated or left connected to the gas supply, is considered an immediate danger to life or property. It will be disconnected, with the householder’s permission, and must not be used until the defects are repaired. For natural gas, if the householder refuses permission to disconnect an installation or individual appliance, the engineer will report the situation to the Gas Emergency Service Provider, which has legal powers to demand entry to make the situation safe or to disconnect the gas supply. The factsheet adds that the provider does not have the same powers with LPG installations.

At Risk

An at risk installation is one where one or more recognised faults are present that could constitute a danger to life or property without further faults developing. With permission, the installation will be turned off and should not be used again until repaired. In a limited number of cases turning off the gas supply will not remove or reduce the risk; then the householder receives a warning notice and is told whom to contact for further investigation.

Not to current standards

Separately, an engineer may say an installation is not in accordance with current standards. The factsheet points out that older installations may not meet today’s requirements without being unsafe, and that bringing one up to current standards is always a good idea but often depends on whether the work can be done at reasonable cost or whether other work, such as a replacement appliance, is planned. It describes only two GIUSP defect categories, so an entry in this category is advice rather than a classification requiring disconnection.

Warning labels and who is responsible

If the Gas Emergency Service Provider attends after a smell of gas or fumes and cannot confirm that the installation is safe, it may attach a “Danger Do Not Use” label and issue a warning notice. The factsheet says that, once a warning notice has been issued, the installation must not be used until checked by a suitably qualified Gas Safe registered engineer, and that it is the householder’s or landlord’s responsibility to arrange the check. The same applies after an engineer identifies an unsafe situation: it is the occupier’s, landlord’s or agent’s responsibility to make sure the installation is not used until it is repaired, and the engineer should tell the landlord or agent where appropriate.

Wider safety advice from HSE

The Health and Safety Executive says it is illegal for anyone to use a gas appliance they suspect is unsafe: turn it off and do not touch it until a Gas Safe registered engineer has checked it. If a gas leak is suspected, call the National Gas Emergency Service on 0800 111 999, open all doors and windows and shut off the gas at the meter control valve if known. HSE also strongly advises that gas appliances, flues and pipework are installed, maintained and serviced at least annually by a Gas Safe registered engineer.

FAQs

Can an engineer disconnect my boiler without my permission?

The Gas Safe factsheet says disconnection is done with the householder’s permission. For natural gas, refusal is reported to the Gas Emergency Service Provider, which has legal powers to enter and make the situation safe.

Does “not to current standards” mean my boiler is unsafe?

No. The factsheet says an older installation may fail current standards without being unsafe, and updating it depends on cost and other planned work.

Who arranges the repair after a Danger Do Not Use label?

The householder or their landlord, according to the factsheet, using a qualified Gas Safe registered engineer.

Bottom line

GIUSP gives engineers a clear framework: an Immediately Dangerous appliance is disconnected, an At Risk appliance is turned off and must be repaired, and neither should be used again until fixed. The responsibility to arrange the repair rests with the householder or landlord. This is general information about Great Britain, not advice on a specific installation.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• Gas Safe Register, “Gas Industry Unsafe Situations Procedure Explained” (PDF, issued 22 April 2024)
• Health and Safety Executive, “Gas safety – Home owners”
• legislation.gov.uk, “The Gas Safety (Installation and Use) Regulations 1998, regulation 30: Installation of gas appliances”

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.

Under the Water Supply (Water Fittings) Regulations 1999, which apply in England and Wales, a permanent mains connection to a closed heating circuit must include an approved backflow prevention device, and a heating system fitted by an installer must also meet the wider requirements for water fittings.

Why backflow matters for a heating circuit

Schedule 2 to the Water Supply (Water Fittings) Regulations 1999, which the legislation marks as applying in England and Wales, says every water system must contain an adequate device or devices for preventing backflow of fluid from any appliance, fitting or process. The device must be appropriate to the highest applicable fluid category downstream before the next such device, and it is adequate if it complies with a specification approved by the regulator. Scotland and Northern Ireland have separate water fittings rules that are not covered here.

Filling a closed heating circuit

Paragraph 24 of Schedule 2 provides that no supply pipe or secondary circuit shall be permanently connected to a closed circuit for filling a heating system unless it incorporates a backflow prevention device in accordance with an approved specification. The Water Regulations Approval Scheme (WRAS) explains this in its installation requirement IRN R360. Where the level of risk is no greater than fluid category 3, the circuit may be filled or topped up through a temporary connection between the primary circuit and the supply pipe, with an approved double check valve at the point of connection to the supply pipe. Alternatively, a permanent connection may be made through a CA backflow prevention device or another no less effective device, fitted in accordance with IRN 510.

Where the level of risk is no greater than fluid category 4, WRAS says a permanent connection may be made through a BA (RPZ) backflow prevention device, which is notifiable under Regulation 5. In practice, the category that applies to a particular heating system depends on the system and the water company’s classification, so it is a question for the installer.

Notification and consent

Regulation 5 requires a person who proposes to install a water fitting in connection with certain listed operations to notify the water undertaker and not begin without its consent, which shall not be withheld unreasonably. The list includes a reduced pressure zone valve assembly or other mechanical device for protection against fluid in category 4 or 5. The requirement does not apply where the fitting is installed by an approved contractor in certain listed cases, including that type of device.

Quality and workmanship

Regulation 4 requires every water fitting to be of an appropriate quality and standard and suitable for its circumstances, to comply with Schedule 2, and to be installed, connected, altered or repaired in a workmanlike manner. Workmanlike means work carried out to an appropriate British Standard or equivalent national specification, to a specification approved by the regulator, or by a method approved by the water undertaker.

Unvented hot water and the boiler

Paragraph 17 of Schedule 2 says every unvented water heater, other than an instantaneous heater of not more than 15 litres capacity, and every secondary coil in a primary system, must be fitted with a temperature control device and either a temperature relief valve or a combined temperature and pressure relief valve, or be capable of accommodating expansion within the secondary hot water system. An expansion valve must be fitted with provision to ensure the discharge is directed correctly if the expansion vessel or system fails. Building Regulations Part G contains separate requirements for the same equipment, covered in a companion guide.

Offences and defences

Regulation 7 makes it an offence, punishable on summary conviction by a fine not exceeding level 3 on the standard scale, to commence a listed operation without notice or consent or in breach of a condition. In proceedings against an owner or occupier for an offence based on installing or altering a water fitting, it is a defence to show the work was done by or under the direction of an approved contractor who certified that the fitting complied with the regulations. A householder therefore has good reason to ask the installer for confirmation of compliance for the work.

FAQs

Is a permanent filling loop always allowed?

Not automatically. WRAS IRN R360 says a permanent connection needs an appropriate backflow device, and the device depends on the fluid category of the circuit.

Do these regulations cover Scotland?

The legislation marks the 1999 Regulations as applying in England and Wales. Scotland has separate water regulations that are not summarised here.

What should I ask my installer?

Ask which backflow prevention device is fitted to the filling connection, who is certifying compliance and whether the water company was notified where regulation 5 required it.

Bottom line

The Water Fittings Regulations 1999 require a backflow prevention device wherever a heating circuit is filled from the mains, notification for higher-risk devices, workmanlike installation and safety devices on unvented hot water systems. Compliance sits with the installer and, for offences, the person who commissioned the work unless an approved contractor certified it. This is general information for England and Wales, not advice on a specific installation.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• legislation.gov.uk, “The Water Supply (Water Fittings) Regulations 1999, Schedule 2: Requirements for water fittings”
• legislation.gov.uk, “The Water Supply (Water Fittings) Regulations 1999, regulation 4: Requirements for water fittings”
• legislation.gov.uk, “The Water Supply (Water Fittings) Regulations 1999, regulation 5: Notification of proposed work”
• legislation.gov.uk, “The Water Supply (Water Fittings) Regulations 1999, regulation 7: Offences”
• Water Regulations Approval Scheme, “IRN R360”

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.

Part J of the Building Regulations requires combustion appliances to have an adequate air supply, safe discharge of combustion products, carbon monoxide detection and protection from fire and burns, and Approved Document J (published for use in England) sets out how to show compliance for a new or replacement gas boiler.

The four requirements that matter to a boiler

Approved Document J, published on GOV.UK for use in England, sets out requirements J1 to J4 for combustion appliances. J1 says appliances must be installed so that there is an adequate supply of air for combustion, to prevent overheating and for the efficient working of any flue. J2 requires adequate provision for discharging the products of combustion to the outside air. J3 requires that where a fixed combustion appliance is provided, appropriate provision is made to detect and warn of the release of carbon monoxide. J4 requires installation that reduces to a reasonable level the risk of burns or of the building catching fire. Requirements J1 and J2 apply to fixed combustion appliances, and J3 applies only to fixed appliances in dwellings.

GOV.UK states that the amended provisions and guidance on carbon monoxide alarms came into effect on 1 October 2022. The document also stresses that following its guidance gives a presumption of compliance, but that presumption can be overturned and other ways of meeting the requirements are permitted.

Air supply

In England, the guidance says combustion appliances need ventilation for combustion and for the proper operation of flues, and that room-sealed appliances, or those with a directly connected external air supply, minimise ventilation energy losses and cold draughts. A room containing an open-flued appliance may need permanently open air vents, depending on the appliance type and rating; infiltration through the building fabric can be enough in some cases. Compartments that enclose open-flued appliances need vents large enough to admit all the air the appliance requires, and cooling air vents at high and low level may be needed where the appliance requires it.

Adjustable vents installed to meet the separate ventilation requirement in Part F cannot substitute for the vents needed for Part J unless they are fixed permanently open. If several appliances share a room, the air supply usually has to be increased.

Flues and how they are checked

In England, Approved Document J says flues should be checked at completion to show they are free from obstruction, satisfactorily gas-tight and made of suitable materials and sizes. Where an appliance is installed, tests should cover the fluepipes and the joints between fluepipes and appliance outlets. A spillage test to check for compliance with J2 should be carried out with the appliance firing, as part of commissioning to check compliance with Part L and, where relevant, the Gas Safety (Installation and Use) Regulations.

For gas appliances the guidance adds that flues should be sized following the manufacturer’s instructions for CE-marked appliances, that connecting fluepipes should match the appliance flue outlet in size, and that outlets should be positioned to allow the dispersal of combustion products and, for balanced flues, the intake of air.

Competence and notification

The document says gas installations must also comply with the Gas Safety (Installation and Use) Regulations, which require gas work to be done by a competent person and gas businesses to be members of a class approved by the Health and Safety Executive, which it says means registration with Gas Safe Register. Because of this, the Building Regulations allow that work need not be notified to a building control body if it solely comprises installing a gas appliance and is done by a member of that approved class.

Carbon monoxide alarms for new or replacement gas appliances

Under the 2022 amendments, where a new or replacement fixed gas burning appliance, excluding gas appliances used solely for cooking, is installed in a dwelling, a carbon monoxide alarm should be provided in the room where the appliance is located. Alarms should comply with BS EN 50291-1:2018 and be battery powered with a battery designed to last the alarm’s working life, with a warning when the alarm is due to expire; mains-powered Type A alarms with fixed wiring and a sensor failure warning may be used instead.

The alarm should be in the same room as the appliance, on the ceiling at least 300mm from any wall or, if on a wall, as high as possible above doors and windows but not within 150mm of the ceiling, and between 1m and 3m horizontally from the appliance. The guidance adds that an alarm should not be regarded as a substitute for correct installation and regular servicing. Similar provisions apply to solid fuel and oil-burning appliances.

FAQs

Does this apply in Scotland, Wales or Northern Ireland?

The GOV.UK publication is the version for use in England. Scotland and Northern Ireland have their own building standards, and readers elsewhere should check the rules that apply in their nation.

Do I need a carbon monoxide alarm if I only replace my boiler?

Approved Document J says an alarm should be provided in the room of a new or replacement fixed gas appliance in a dwelling, other than a gas appliance used solely for cooking.

Does an alarm replace a boiler service?

No. The guidance states that an alarm should not be regarded as a substitute for correct installation and regular servicing.

Bottom line

For a gas boiler in England, Part J means adequate air, a sound and tested flue and, since 1 October 2022, a carbon monoxide alarm in the same room for a new or replacement appliance. A Gas Safe registered installer is expected to handle competence and notification. This is general information, not advice on any specific installation; confirm the details with your installer and local building control body.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• Ministry of Housing, Communities & Local Government via GOV.UK, “Combustion appliances and fuel storage systems: Approved Document J”
• Ministry of Housing, Communities & Local Government via GOV.UK, “Approved Document J: Combustion appliances and fuel storage systems” (PDF, 2022 amendments)

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.

HSE says asbestos may be found in any building built or refurbished before the year 2000, including in asbestos cement flues and in lagging on pipes and boilers, so tell your installer about any you know of or suspect before work starts.

Why the age of the property matters

HSE says asbestos was widely used in commercial buildings, homes and machinery until it was banned in 1999. It advises that asbestos may be part of any commercial or domestic building built or refurbished before the year 2000. The guidance below is from HSE, which regulates in Great Britain, and refers to the Control of Asbestos Regulations 2012; if you live in Northern Ireland, check the position there separately.

HSE notes that asbestos is common in the general environment, but that working directly with asbestos-containing materials can give personal exposures to airborne asbestos much higher than normal environmental levels, which is why disturbance during building work is the concern.

Where it may be found near a boiler

HSE lists places asbestos can typically still be found, including asbestos cement products such as pipes, flues and roofs; lagging on pipes and boilers; water tanks and toilet cisterns; asbestos insulating board, which closely resembles typical plasterboard; loose asbestos in ceiling and wall cavities; sprayed coatings; textured decorative coatings such as Artex; and floor tiles. Of these, flues and lagging on pipes and boilers are the items most directly relevant to a boiler replacement.

What HSE says householders should do

HSE says not to try to repair or remove asbestos materials yourself if you have not had training for non-licensed asbestos work, and suggests seeking advice from an environmental health officer at the local council. GOV.UK’s page on asbestos in your home also points you to your local council for information about asbestos and its disposal. If you are sure or strongly suspect your home contains asbestos, HSE says it is often best to leave materials where they are, especially if they are in good condition and unlikely to be damaged, and to check them from time to time. Sprayed coatings, lagging or insulation and asbestos insulating board should only be removed by a contractor licensed by HSE.

HSE adds that slightly damaged asbestos-containing materials can sometimes be repaired by sealing or enclosing them, but only by someone with the necessary training, and that badly damaged material likely to be damaged further should be removed if it cannot be protected.

Telling your installer

If you bring in builders, maintenance workers or contractors, HSE says you should tell them about any asbestos materials in your home before they start. This helps reduce the risk that they disturb it, and HSE strongly encourages the use of trained professionals to repair or remove asbestos-containing materials. It says tradespeople and maintenance workers who disturb the fabric of buildings are those considered most at risk of exposure. Consider asking the quote to say who will deal with asbestos if it is found, and what happens to your timetable and costs if work has to stop.

The legal position, waste and second-hand items

HSE explains that the general duties in section 3(1) of the Health and Safety at Work etc Act 1974 apply to protect householders from risks from work activities carried out in their homes, and that where work involves asbestos-containing materials, the Control of Asbestos Regulations 2012 also apply, in particular regulations 11, 15 and 16. In owner-occupied homes, it says owners are not legally responsible for risks to contractors from asbestos, because owners are not themselves engaged in a work activity. Asbestos-containing materials must be legally disposed of as hazardous waste and not mixed with ordinary household waste, so contact your local authority about collection or facilities. HSE also says it is illegal to supply any article containing asbestos, whether for money or free of charge.

FAQs

Does having asbestos in my home mean I must have it removed?

Not necessarily. In its guidance on asbestos in buildings, HSE says the presence of asbestos alone should not be a cause for concern and that it only becomes a risk to health when released into the air and breathed in. Materials in good condition and unlikely to be damaged can often be left in place and monitored.

Can I remove an asbestos flue myself?

HSE advises against repairing or removing asbestos materials yourself if you are untrained, and says some materials must only be removed by an HSE-licensed contractor. Ask your local council for advice.

Does this apply in Northern Ireland?

HSE’s guidance and the Control of Asbestos Regulations 2012 apply in Great Britain. If you live in Northern Ireland, check the position with the relevant authority there.

Bottom line

If your home was built or refurbished before 2000, assume asbestos may be present in materials near your boiler and flue, tell your installer before work begins and let a trained or licensed professional handle anything you cannot rule out. This is general safety information; ask your local council or HSE for advice on your situation.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• Health and Safety Executive, “Asbestos: frequently asked questions”
• GOV.UK, “Asbestos in your home”

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.

Under section 49 of the Consumer Rights Act 2015, every consumer contract to supply a service includes a term that the trader must perform it with reasonable care and skill, and sections 54 to 56 set out what you can require if they do not.

Goods and services are treated separately

Our guide to boiler faults explains the Consumer Rights Act 2015 remedies for faulty goods. Installation, by contrast, is a service, and Part 1, Chapter 4 of the Act deals with services contracts. The legislation shows that these provisions extend to England, Wales, Scotland and Northern Ireland, so the rights described here apply UK-wide, although the courts and procedures for enforcing them differ between the nations.

The reasonable care and skill term

Section 49 says every contract to supply a service is to be treated as including a term that the trader must perform the service with reasonable care and skill. Section 49 does not itself set out technical standards; what is reasonable in a particular installation depends on the facts, which is one reason evidence such as photographs, commissioning records and independent engineer reports can matter. Safety concerns about gas work are handled through Gas Safe Register and the Health and Safety Executive, as our complaints guide explains.

Repeat performance

If the service does not conform, section 54 lists the consumer’s rights: to require repeat performance (section 55) and to a price reduction (section 56). Repeat performance means requiring the trader to perform the service again, to the extent needed to complete it in line with the contract. Under section 55 the trader must do so within a reasonable time and without significant inconvenience to you, and must bear any necessary costs, including labour and materials. You cannot require repeat performance if completing the service in line with the contract is impossible, and what counts as a reasonable time or significant inconvenience depends on the nature of the service and its purpose.

Section 54 also gives a right to a price reduction in two further situations: where the trader breaches a term about information it gave that section 50 treats as part of the contract but which does not relate to the service itself, and where it breaches the requirement under section 52 to perform within a reasonable time.

Price reduction and refunds

Section 56 gives a right to require the trader to reduce the price by an appropriate amount, including a refund of anything you have already paid above the reduced amount, and the reduction may be the full price where appropriate. If you have both rights, you can go for a price reduction only where repeat performance is impossible, or where you asked for it and the trader failed to provide it within a reasonable time and without significant inconvenience. A refund must be given without undue delay and in any event within 14 days of the trader agreeing you are entitled to it, using the same means of payment you used unless you agree otherwise, and without a fee.

Other remedies and contract terms

Section 54 also says these rights do not stop you seeking other remedies for breach, either instead of or as well as those rights, though you cannot recover twice for the same loss. It lists claiming damages, recovering money where the consideration for payment has failed, seeking specific performance or implement, relying on the breach against a claim by the trader, and treating the contract as at an end where that is open to you. Section 57 makes a term of a services contract non-binding to the extent it would exclude the trader’s liability under section 49, so a “no liability for workmanship” clause cannot remove your rights. Take legal advice before relying on these remedies in a dispute.

FAQs

Does this replace complaining to Gas Safe Register?

No. Gas Safe Register deals with the safety and competence of gas work, while the Consumer Rights Act rights concern the contract. They can be used together where an issue covers both.

Can I ask for a refund straight away?

Not necessarily. Section 56 generally allows a price reduction only if repeat performance is impossible or the trader has failed to provide it in time; other remedies in section 54 may be available depending on the facts.

Does the trader have to carry out the repeat work at its own cost?

Yes. Section 55 says the trader must bear any necessary costs of repeat performance, including labour and materials.

How quickly must the installer put things right?

Section 55 says repeat performance must be provided within a reasonable time and without significant inconvenience to you, and that what is reasonable is judged by the nature of the service and the purpose for which it was performed.

Bottom line

If the way your boiler was installed was not done with reasonable care and skill, the Consumer Rights Act lets you require the work to be redone at the trader’s cost or, in defined circumstances, a price reduction up to the full price, and the trader cannot contract out of that duty. Keep records, write to the installer setting out the defects and a reasonable deadline, and take advice before escalating. This is general information, not legal advice.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• legislation.gov.uk, “Consumer Rights Act 2015, section 49”
• legislation.gov.uk, “Consumer Rights Act 2015, section 54”
• legislation.gov.uk, “Consumer Rights Act 2015, section 55”
• legislation.gov.uk, “Consumer Rights Act 2015, section 56”
• legislation.gov.uk, “Consumer Rights Act 2015, section 57”

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.

If you smell gas or suspect a leak, HSE and National Gas both say to call the free National Gas Emergency Service on 0800 111 999, open doors and windows and shut off the gas at the meter if you know how.

Call the National Gas Emergency Service

National Gas says that if you smell gas or suspect a leak you should call the National Gas Emergency Service on 0800 111 999, which is open 24 hours a day and free to call. It says to use the same number to report a gas or carbon monoxide emergency, or if a gas pipeline has been struck, even if no gas leak has occurred. HSE’s guidance for home owners gives the same number. National Gas notes that calls are recorded and may be monitored, and that British Sign Language users can use SignLive to contact the service free of charge. This guidance comes from bodies operating in Great Britain.

What to do straight away

National Gas says that in an emergency you should not smoke or light matches, should not turn electrical switches on or off, should open doors and windows, should turn off the meter at the control handle unless the meter is in a cellar, and should call the emergency number. HSE says that if you suspect a gas leak you should call the emergency number, open all doors and windows and shut off the gas supply at the meter control valve if you know where it is.

If you suspect an appliance is unsafe

HSE says it is illegal for anyone to use a gas appliance if they suspect it is unsafe. Turn the appliance off and do not touch it until it has been checked by a Gas Safe registered engineer. National Gas lists signs of a faulty boiler: soot around the appliance, a yellow or orange weak flame instead of a blue one, and a pilot light that blows out easily. In rented homes it advises speaking to your landlord about annual servicing and asking for a copy of the safety certificate.

Carbon monoxide: warning signs and response

National Gas lists symptoms of carbon monoxide poisoning as nausea, light-headedness, headaches, shortness of breath, dizziness and sleepiness, and says it can be fatal. If a carbon monoxide alarm sounds or you suspect a leak, it says to stop using all appliances and switch them off, open doors and windows, and evacuate the property immediately. Then call the National Gas Emergency Service on 0800 111 999 or the HSE Gas Safety Advice Line on 0800 300 363, and do not go back in until you have been given advice. It also says to seek immediate medical help because you may not realise you have been affected, and that going outside into fresh air does not treat exposure by itself. This is not medical advice; ask for help urgently.

Alarms, servicing and hiring the right engineer

HSE strongly recommends carbon monoxide alarms as one useful precaution but says they are not a replacement for regular maintenance and safety checks. It says an alarm should comply with British Standard EN 50291 and carry a British or European approval mark, such as a Kitemark, and be installed and maintained according to the manufacturer’s instructions. HSE strongly advises that all gas appliances, flues and pipework are installed, regularly maintained and serviced at least annually by a Gas Safe registered engineer, and says never to block ventilation and to keep flues clear. Anyone employed to work on gas appliances in a home must be Gas Safe registered and competent in that area of gas work, which is shown on the back of the engineer’s ID card.

FAQs

Should I call my boiler engineer first if I smell gas?

National Gas and HSE both give the National Gas Emergency Service number, 0800 111 999, as the number to call for a suspected gas leak. Contact your engineer afterwards for repairs and checks.

What if I hit a gas pipe during building work?

National Gas says that if you or your builders have hit a gas pipe, you should call the National Gas Emergency Service on 0800 111 999, day or night.

Can I keep using the boiler if I only suspect a fault?

HSE says it is illegal to use a gas appliance if you suspect it is unsafe. Turn it off and have a Gas Safe registered engineer check it.

Bottom line

The guidance is consistent: call 0800 111 999, open doors and windows, avoid flames and switches, and shut off the gas at the meter if you can do so safely. Do not use an appliance you think is unsafe until a Gas Safe registered engineer has checked it, and fit and maintain a carbon monoxide alarm. This is general safety information, not medical or engineering advice.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• National Gas, “Emergency Contacts”
• Health and Safety Executive, “Domestic gas: frequently asked questions”

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.

Planning permission is not normally required to install or replace a boiler when all the work is internal, and an external flue is normally permitted development in England if certain conditions are met.

Internal boiler work

The Planning Portal, which describes the planning system in England (and notes that policy in Wales may differ), says planning permission is not normally required for installing or replacing a boiler or heating system if all the work is internal. It adds that if you live in a listed building you should check with your local planning authority first, because consent is also likely to be needed for internal alterations there. Planning is separate from Building Regulations and gas safety law, which are covered in other guides on this site.

External flues: the permitted development conditions

Where a boiler needs an outside flue, the Planning Portal says fitting, altering or replacing an external flue is normally permitted development, so no planning application is needed, if conditions are met. On the rear or side elevation of the building, the flue may rise to a maximum of one metre above the highest part of the roof. The government’s technical guidance on permitted development for householders sets out the same limit in Class G: development is not permitted if the flue would exceed the highest part of the roof by 1 metre or more. Class G covers the installation, alteration or replacement of a chimney, flue or soil and vent pipe on a dwellinghouse.

Conservation areas and other designated land

In designated areas, the Planning Portal says the flue should not be fitted on the principal or side elevation that fronts a highway. It lists conservation areas, World Heritage Sites, national parks, areas of outstanding natural beauty and the Broads. The government’s guidance uses the term “article 2(3) land” for these areas and says Class G does not permit a flue on a wall or roof slope that fronts a highway and forms the principal or a side elevation of the dwellinghouse. Even where you have permitted development rights, the Planning Portal advises checking with the local planning authority before a flue is fitted in a listed building or a designated area.

When the permitted development allowance does not apply

The Planning Portal states that these permitted development allowances apply to houses, not to flats and maisonettes, converted houses or houses created through certain permitted development change-of-use rights, new dwellinghouses created under Part 20 of Schedule 2, or other buildings. They also do not apply in areas where a planning condition, an Article 4 Direction or another restriction limits permitted development rights. The technical guidance adds that Class G does not apply to a dwellinghouse where permission to use it as a dwelling was granted only by virtue of Class M, N, P, PA or Q of Part 3 of the Schedule.

Fuel stores, other structures and local advice

If a project needs an outside building to store fuel or related equipment, the Planning Portal says the same rules apply to it as to other extensions and garden outbuildings. It also notes additional rights exist for flues serving biomass and combined heat and power systems. Its guidance is introductory rather than definitive, local rules may also affect what is needed, and local planning authorities may charge a fee for pre-application advice, so confirm your situation with the council before work begins.

The Planning Portal strongly advises reading the government’s technical guidance on permitted development for householders. That guidance introduces permitted development rights as allowing householders to improve and extend their homes without applying for planning permission where that would be out of proportion with the impact of the works, and it says all the relevant Parts and Classes of the Order need to be considered together when judging whether a proposal is permitted development.

FAQs

Does a boiler swap ever need planning permission?

Not normally when all work is internal, according to the Planning Portal, but listed buildings and designated areas need extra checks and an external flue must meet the permitted development conditions.

Does this apply in Wales, Scotland or Northern Ireland?

The Planning Portal pages and the technical guidance relate to England, and the Planning Portal says Welsh policy may differ. Scotland and Northern Ireland have their own planning systems, so check with the local council.

Who decides if my house has permitted development rights?

The local planning authority. The Planning Portal says a planning condition, Article 4 Direction or other restriction can limit permitted development rights, so ask the council if you are unsure.

Does replacing an existing flue count?

Yes. The Planning Portal describes fitting, altering or replacing an external flue as normally permitted development if the conditions are met, and Class G in the technical guidance likewise covers the installation, alteration or replacement of a flue on a dwellinghouse.

Bottom line

For most homes in England, a like-for-like boiler replacement with an internal route needs no planning application, while a new external flue is permitted development if it stays within one metre of the roof line and, in designated areas, is not on a principal or side elevation facing the road. Flats, converted houses and listed buildings need extra care, so check with your local planning authority. This is general information, not planning advice.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• Planning Portal, “Planning permission – Boilers and heating”
• Planning Portal, “Planning Permission – Flue, chimney or soil and vent pipe”
• GOV.UK, “Permitted development rights for householders: technical guidance”

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.

Requirement G3 of the Building Regulations sets out how a hot water system with a storage vessel must be designed and installed in England, and it treats unvented cylinders as notifiable work unless the installer belongs to a competent person scheme.

What Requirement G3 says

Approved Document G, the government guidance on Part G of the Building Regulations 2010, applies to work in England (GOV.UK also says it applies to building work on excepted energy buildings in Wales, so if you live elsewhere, check the requirements that apply in your nation). Requirement G3(2) says a hot water system, including any cistern or vessel that supplies or receives expansion water from it, must be designed, constructed and installed to resist the effects of temperature and pressure that may occur in normal use or in reasonably anticipated malfunctions, and be adequately supported.

Requirement G3(3) says a system with a hot water storage vessel must include precautions to prevent the stored water exceeding 100°C and to ensure any discharge from safety devices is conveyed to where it is visible but will not endanger anyone in or around the building. G3(4), a 48°C limit on water delivered to a fixed bath, applies only when a dwelling is newly erected or formed by a material change of use.

Safety devices

Approved Document G says unvented storage systems should incorporate at least two independent safety devices, in addition to the thermostat that controls the stored water temperature. An acceptable approach it describes is a non-self-resetting energy cut-out that disconnects the heat supply if the system overheats, plus a temperature relief valve or a combined temperature and pressure relief valve to discharge water safely in serious overheating; alternatives are acceptable if they give equivalent safety. Where the indirect heat supply comes from a boiler, the energy cut-out may be on the boiler.

Packaged units and labelling

For unvented systems of up to 500 litres and under 45kW, the guidance says the system should be a proprietary unit or package that meets an appropriate standard, giving BS EN 12897:2006 as an example. The unit should be permanently marked with the manufacturer’s details, model reference, rated capacity, operating pressures and data on each safety device, and carry a warning to the user not to remove or adjust components and to switch the heater off and contact the installer if, for example, hot water flows from the discharge pipe. A warning to the installer that the installation is subject to the Building Regulations, with the installer’s name, address and completion date, is also shown.

Discharge pipework: tundish and pipe runs

Safety devices should discharge, directly or through a manifold, via a short length of metal pipe to a tundish. The guidance says the tundish should be vertical, in the same space as the cylinder, fitted as close as possible to and lower than the safety device, with no more than 600mm of pipe between them, and any discharge should be visible at the tundish. The discharge pipe from the tundish should end in a safe place where there is no risk to people nearby and should be at least one pipe size larger than the safety device outlet, with larger sizes needed for long or complex runs. It warns that discharge can be high-temperature water and steam, which may damage asphalt, roofing felt and non-metallic rainwater goods.

Notification, competent persons and certificates

Installing an unvented system is notifiable building work that must be notified to the building control body before work starts. However, the guidance says that if the installer is registered with a competent person scheme for unvented hot water systems, advance notification is not needed: the installer self-certifies that the work complies, and the owner or occupier is given a certificate of compliance, usually issued by the scheme operator. It also says good workmanship is essential and that where commissioning is carried out it must follow a procedure approved by the Secretary of State, which for dwellings is set out in the Domestic Heating Compliance Guide.

FAQs

Does this apply if I have a combi boiler and no cylinder?

Not in the same way. Requirement G3(3) and the unvented storage guidance apply to systems with a hot water storage vessel, so ask your installer whether your proposed system includes one.

What should I ask my installer?

Ask whether they are registered with a competent person scheme for unvented systems, whether the cylinder is a labelled proprietary package, where the tundish and discharge pipe will be, and how you will receive the certificate of compliance.

Is the same guidance used in Scotland, Wales and Northern Ireland?

GOV.UK says Approved Document G takes effect for use in England and also applies to work on excepted energy buildings in Wales. If you live elsewhere in the UK, check the building requirements that apply in your nation.

Bottom line

An unvented cylinder can be installed safely and legally, but only if it has suitable independent safety devices, properly arranged discharge pipework and the right paperwork. In England, expect either building control notification or a competent person certificate. This is general information; always confirm details with your installer and building control body.

Sources

This guide draws on the following primary sources, current as of 20 September 2026:

• Ministry of Housing, Communities & Local Government via GOV.UK, “Approved Document G: Sanitation, hot water safety and water efficiency” (PDF)
• GOV.UK, “Sanitation, hot water safety and water efficiency: Approved Document G”

Related guides

Best Boiler Deals is an independent guide. We may earn a fee from some links; this never affects what we write. This article is general information, not regulated advice on any specific installation — always confirm the details with a Gas Safe registered engineer.