Under the April 2026 domestic Technical Handbook, Scotland allows a central heating system in a house to be installed without a building warrant, but the work must still meet the standards, including standards 3.17 to 3.22 on combustion appliances and carbon monoxide detection.

Is a building warrant needed?

The domestic Technical Handbook, April 2026 edition, applies in Scotland only and covers building warrant applications submitted on or after 6 April 2026 and works not requiring a warrant from that date. Section 0.5 explains that regulation 5 and schedule 3 set out work that can be done without a building warrant, but that such work must still comply with the regulations.

For houses, building type 1 allows much of the work to proceed without a warrant. The Handbook’s examples include small penetrations of external walls or roofs such as balanced flues, electrical work and a central heating system. The exceptions include increasing the floor area, altering the roof, external walls or structural elements (for instance building a masonry chimney through the roof), work adversely affecting a separating wall and work changing wastewater discharge. Local council building standards departments can advise where there is doubt.

Standards still apply

The Handbook stresses that exempt work is not exempt from the standards. For combustion appliances the relevant guidance sits in standards 3.17 to 3.22, covering safe operation, protection from combustion products, relationship to combustible materials, removal of products of combustion, and air for combustion and cooling. The guidance is aimed at solid fuel appliances rated up to 50 kW, oil-firing appliances up to 45 kW and gas-fired appliances up to 70 kW net input. Larger installations are expected to be designed by specialists.

Gas, oil and solid fuel installers

For gas appliances, the Handbook says installations must also comply with the Gas Safety (Installation and Use) Regulations 1998, which require a competent person, and that Gas Safe Register is the only registration scheme recognised by the Health and Safety Executive that complies with those Regulations. For oil, it says equipment should meet the relevant OFTEC standard and installation should follow BS 5410, with a fire valve fitted so as to cut off the oil supply remotely, located externally to the dwelling. Solid fuel installations should follow BS 8303:2018, and HETAS operates a registration scheme for solid fuel engineers.

The Handbook adds that OFTEC and HETAS schemes only have mandatory status where legislation specifically refers to them.

Bathrooms, bedrooms and flues

Under standard 3.20, open-flued oil-firing appliances should not be installed in bathrooms, shower rooms or sleeping accommodation, or in cupboards connecting directly with them, and a room-sealed appliance is the appropriate alternative where placing an appliance there cannot be avoided. For gas, the Handbook points to regulation 30 of the Gas Safety (Installation and Use) Regulations 1998, which has specific requirements for room-sealed appliances in those locations. Metal chimneys should be guarded where there is a risk of damage or a hidden risk to people.

Carbon monoxide detection

Clause 3.20.20 says a detection system should be installed in a dwelling where a new or replacement fixed combustion appliance, excluding one used solely for cooking, is installed in the dwelling or in an interconnected space such as an integral garage. Detectors should comply with BS EN 50291-1:2010, include an integral sounder and be battery powered for the working life of the detector, with an end-of-life warning. Hard-wired Type A detectors with fixed wiring and a sensor failure warning are an alternative.

The Handbook says the system should have at least one detector in every space containing a fixed combustion appliance, excluding cooking-only appliances, and one detector in a bedroom or principal habitable room where a flue passes through it. Ceiling-mounted detectors should be at least 300mm from any wall, and wall-mounted ones at least 150mm below the ceiling and higher than any door or window. In the appliance room the detector should be 1m to 3m from the appliance, or placed at that distance outside the space if it is too small.

FAQs

Does a central heating replacement in a Scottish house need a warrant?

The Handbook lists a central heating system among the work in a house that does not need a warrant, subject to the exceptions, but the work must still meet the standards.

Is the Gas Safe Register needed in Scotland?

The Handbook says gas installations must comply with the Gas Safety (Installation and Use) Regulations 1998, which require a competent person, and Gas Safe Register is the scheme recognised by the Health and Safety Executive.

Does this apply to England, Wales or Northern Ireland?

No. The Handbook applies to Scotland only.

Bottom line

In Scotland, replacing a boiler in a house normally falls within the work that does not need a building warrant, but the standards for flues, air supply and carbon monoxide detection still apply, and gas work must be done by a competent, Gas Safe registered installer. This is general information, not advice on any specific installation; the installer and the local council’s building standards department can confirm the position.

Sources

This guide draws on the following primary sources, current as of 21 September 2026:

• Scottish Government, “Building standards technical handbook: domestic, April 2026”
• mygov.scot, “Getting a building warrant”

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.