Heating, Energy & Eco
398 sources in the library on heating, energy & eco. Each one says what the document covers and what it is good for. Name a source to see which document it is and where to read it. One at a time. Page 7 of 10.
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Welsh Government (gov.wales)
The Welsh Approved Document L Volume 1, in force until 3 March 2027, and the source for Welsh window figures, which are not identical to England's. Table 10.1 sets, for new and replacement windows and roof windows, a maximum U-value of 1.4 W/(m2K) or WER Band B, with an alternative for replacements of 1.2 W/(m2K) centre pane or low-E secondary glazing, and a threshold U-value for retained windows of 3.3. Rooflights: 2.2 for new and replacement, threshold 3.8. Doors more than 60 per cent glazed: 1.4 or DSER Band C, alternative 1.2 centre pane, threshold 3.3. All other doors: 1.4 or DSER Band B, threshold 3.3. External fire doorsets as defined in Approved Document B Volume 1 may be 1.8. Transitional easements allowed timber windows at 1.6 or WER Band C and timber doors at 1.8 or DSER Band E only where a building notice, initial notice or full plans were given before 23 November 2023. Paragraph 11.35 requires an existing window or door worse than the column (c) threshold to be replaced to column (a); paragraph 11.37 states that windows and doors mean the whole unit including the frame, so replacing just the glazing or the door leaf while retaining the existing frame is not building work and does not have to meet the energy efficiency requirements, though upgrading as close as practicable is sensible; paragraph 11.38 caps the total area of windows and doors at 25 per cent of total floor area where one is enlarged or created.
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Welsh Government (gov.wales)
The Welsh Government landing page that shows which edition of Approved Document L applies in Wales and when. Two editions of Volume 1 (dwellings) sit side by side: the current edition in force until 3 March 2027 at /sites/default/files/publications/2024-05/building-regulations-approved-document-l-vol-1.pdf, and the 2026 edition in force from 4 March 2027 at /sites/default/files/publications/2026-04/building-regulations-approved-document-l-vol-1-2026.pdf. Note the date differs from England, where the 2026 edition of Approved Document L takes effect on 24 March 2027, so a note giving a single UK-wide changeover date is wrong for Wales by three weeks.
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BBA (British Board of Agrement)
The certification body whose Agrement Certificate is what a note usually means when it says a system is approved, and the page that lists which schemes it actually runs. The BBA's certification team issues certificates for the BBA Agrement, HAPAS (Highways Authority Product Approval Services), European Technical Assessment (ETA), and the Microgeneration Certification Scheme. Alongside product certification it runs certification of people, including the BBA Approved Installer Scheme, the BBA Competent Person Scheme, the BBA Gas Membrane Approved Installer Scheme, TrustMark registration and the BBA PAS 2030 Scheme, plus a Client Managed Inspection Service. Its testing services are also available standalone and include durability, mechanical, physical and structural, weather resistance and wind serviceability, conformance and fit-for-purpose, thermal performance, and onsite testing and trials. An Agrement Certificate is the route by which a product without a harmonised European product standard, such as a tanking membrane, a multifoil or a proprietary EWI system, gets an independently assessed statement of fitness for a stated use.
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BRE (Building Research Establishment)
The document that decides how a U-value must be calculated in the UK, so it is the arbiter when a manufacturer's claimed U-value and a building control assessment disagree. Published by BRE Electronic Publications, authors Brian Anderson and Ludmilla Kosmina, A4, 80 pages, published date 18 November 2020, ISBN 9781848064812, and section 11.1 has been updated since the 2019 publication with the update appended at the end. It concerns the calculated U-values of new building elements including walls, roofs, floors, windows and doors. Section 3 gives guidance on thermal conductivity of materials, section 4 on the issues that commonly arise in a U-value calculation, and sections 7 to 14 on the individual construction element types, identifying which section 4 issues apply to which construction. It deliberately does not reproduce the calculation methods themselves, referring the reader to the relevant British Standards, which is why it is a conventions document rather than a method. The 2002 edition remains available separately.
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BRE (Building Research Establishment)
The methodology behind every EPC band, published and maintained by BRE. SAP is the UK Government's National Calculation Methodology for assessing the energy performance of dwellings, used both for Building Regulations compliance and for producing Energy Performance Certificates, and it feeds national, devolved and local government policy. It was first published in 1993 and revised in 1998, 2001, 2005, 2009 and 2012; SAP 10 came into use from June 2022 in England and later that year in Wales and Scotland. The site also hosts BRE Technical Notes, which are the mechanism by which a particular technology becomes recognised in a SAP or RdSAP assessment, so a product that claims an EPC benefit should have one. Governance sits with the SAP Scientific Integrity Group, which protects the integrity and impartiality of the model, and the SAP Industry Forum.
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BRE Group
Important currency point for any note mentioning certification schemes: the Home Quality Mark no longer exists under that name. BRE has folded it into the BREEAM product range as BREEAM UK New Construction: Residential, with version 6.1 released in April 2025. HQM led residential sustainability assessment in the UK from 2015 with more than 50,000 homes registered. The scheme assesses homes against three sustainability indicators covering environmental performance (carbon emissions, resource efficiency, biodiversity, circular design), social performance (occupant health and wellbeing, indoor air quality, daylight, thermal comfort, noise, access to green space) and economic performance (efficient use of materials, future-ready infrastructure, running costs, adaptability). Homes are rated on a scale from pass to outstanding. BRE states the certification recognises performance BEYOND minimum regulations only, and that certification can open access to green mortgages and investment incentives. Separately, BREEAM Refurbishment and Fit-Out (currently V7) is the BREEAM standard covering refurbishment rather than new build, and BREEAM has run third-party certified standards since 1990.
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BSI (British Standards Institution)
STATUS: CURRENT. BS 5440-1:2023 was published 12 December 2023 and supersedes BS 5440-1:2008 and BS 5440-1:2000; a note citing an undated BS 5440 or the 2000 edition should be updated. It specifies requirements for installing gas appliances to chimneys, the chimney work a gas engineer undertakes under UK conditions, and the maintenance of chimneys. It applies to open flued chimneys for Type B appliances and room sealed chimneys for Type C appliances of rated input not exceeding 70 kW net burning 1st, 2nd or 3rd family gases, natural or fanned draught, whether the chimney is supplied with the appliance or separately, and it complements BS EN 15287-1 and BS EN 15287-2 with UK specific requirements. It excludes gas fired incinerators, leisure accommodation vehicles and hydrogen only appliances. Part 2 (BS 5440-2:2023) covers ventilation provision. Catalogue page confirms number, title, date, status and scope; requirements are paywalled.
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BSI (British Standards Institution)
STATUS: CURRENT. BS 6172:2010+A1:2017 was published 31 July 2017 and supersedes BS 6172:2010, which superseded BS 6172:2004 and BS 6172:1990. It specifies requirements for the safe installation, servicing and maintenance of domestic gas cooking appliances, with installation defined to include design, inspection and commissioning, and it applies to new, previously used and second hand appliances in dwellings, leisure accommodation vehicles, residential park homes and permanently moored boats, but not towed or motorised caravans. The A1:2017 amendment reflects European changes allowing gas cooker hoses and sockets to BS EN 14800 and gas hose connection valves to BS EN 15069. This is the standard behind a kitchen note's statement that a gas hob or cooker must be connected by a Gas Safe registered engineer, and it works with BS 5440-2 for ventilation. Catalogue page confirms number, title, date, status, supersession and scope.
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BSI (British Standards Institution)
The code of practice behind system cleaning, inhibitor dosing and magnetic filters, and the standard to cite when explaining why a radiator develops a pinhole leak in the first place. Published 31 May 2019 and Current. It is the industry code of practice on how to prepare the circulating water during initial commissioning or re-commissioning of domestic central heating and cooling water systems, and it also covers ongoing water treatment so that systems perform efficiently and are protected against premature failure. Its audience is boiler manufacturers, central heating installers and central heating maintenance contractors, which is why a boiler warranty commonly requires compliance with it: pinhole corrosion in a radiator is the visible end point of untreated system water, so the remedy a note recommends should be system cleaning and inhibitor to BS 7593 rather than a sealant alone.
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BSI (British Standards Institution)
STATUS: WITHDRAWN on 28 May 2021, superseded by BS EN 1264-1:2021. BS EN 1264-1:2011 was published 31 July 2011 and gave the definitions and symbols for water based heating and cooling systems embedded into the enclosure surfaces of the room being heated or cooled, in residential, office and similar buildings, and it also covered heating media other than water. It is part one of the five part series that governs underfloor heating design: -2 thermal output by calculation and test, -3 dimensioning, -4 installation, -5 thermal output for wall and ceiling heating and for cooling. The whole series was reissued in 2021, so a note citing any BS EN 1264 part with a 2009 or 2011 date is quoting a withdrawn edition; an undated citation of BS EN 1264 is safe. Catalogue page confirms number, title, publication date, withdrawal date and scope.
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BSI (British Standards Institution)
Part 1 of the four-part standard that defines how a heat pump's rated capacity and COP are stated, so it underpins any performance figure quoted in a heat pump note. Published 31 Mar 2018 and withdrawn 12 Sep 2022 in favour of the 2022 edition, so cite it for the definitions rather than as current. It applies to factory-made units that can be ducted, factory-made liquid chilling packages with integral or remote condensers, fixed and variable capacity units, and air-to-air air conditioners that evaporate condensate on the condenser side. Packaged, single split and multi split systems are covered, as are single duct and double duct units. For units made of several parts it applies only to those designed and supplied as a complete package, except liquid chilling packages with remote condensers. Note 1 to the scope directs part load testing to EN 14825, which is where the seasonal figures SCOP and SEER come from.
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BSI (British Standards Institution)
The standard covering fan assisted radiators, convectors and trench convectors, that is exactly the products BS EN 442-2 excludes, so this is the reference for skirting heating and low-temperature fan coil emitters. Published 31 Dec 2014, current but under review. It defines the technical specifications and requirements for fan assisted radiators, convectors and trench convectors for permanent installation in central heating systems, whether factory assembled or supplied as kits, fed with water at temperatures below 120 degrees C from a remote heating source. It also applies to radiators and convectors covered by EN 442-1 for the purpose of determining their dry cooling capacity, and it does not apply to discrete heating appliances. It sets the testing basis for determining thermal output and dry cooling capacity and requires manufacturers to supply the additional common data needed for correct application, which is why a fan assisted emitter's output must be read against this standard rather than compared directly with a delta T50 radiator figure.
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Chartered Institution of Building Services Engineers
The design guide a heating engineer sizes a domestic system from, and the right citation for any note about radiator or cylinder sizing. Publisher CIBSE, status Active, 415 pages, publication date January 2026, ISBN 9781918034196, priced GBP 45 plus VAT for the book and GBP 60 plus VAT for the PDF at standard rate, so the text itself is paywalled and only the catalogue page is public. The catalogue page confirms what the 2026 edition changed: heat loss assessment now follows the BS EN 12831-1:2017 method, domestic hot water cylinder sizing follows BS EN 12831-3:2017 including sizing for storage below 60 degrees C and a thermal disinfection procedure, U-value tables have been updated for modern construction methods, and the latest CIBSE weather data is used with 28 zones and four outdoor design temperatures. It also introduces a System Criteria Document recording design decisions and client and designer sign-off, explicitly in line with the Building Safety Act, plus a new controls section and expanded hydraulic and system configurations. Note the versioning trap: version 2026-02 published in July 2026 supersedes version 2026-01, and CIBSE advises reading the accompanying corrigendum alongside the guide.
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Chartered Institution of Building Services Engineers
The core CIBSE reference for design criteria and calculation methods, cited whenever a note needs an authority for indoor design temperatures, fabric performance or heat loss and ventilation sizing. Publisher CIBSE, status Active, 402 pages, publication date March 2015 with a 2021 update, ISBN 9781906846541. The text is paywalled at GBP 200 plus VAT standard rate for the book and GBP 150 plus VAT for the download, free to CIBSE members, so only the catalogue page is public. The page confirms the scope: design criteria and calculation methods covering fabric performance, heating and ventilation system sizing, methods for thermal comfort evaluation and energy demand. Two currency notes recorded on the page matter for anyone citing it: Chapter 2 of Guide A supersedes TM34 Weather data with climate change scenarios (2004), and the Guide references BS EN 779:2012 for air filters, which has since been superseded by BS EN ISO 16890. The supplementary data files are downloadable free and include external design data, UK wind roses (Figure 2.8), solar irradiation on inclined planes (Table 2.12), sol-air temperatures (Table 2.14) and UK cooling load tables (Tables 5.16 and 5.17).
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Chartered Institution of Building Services Engineers
TM59 is the dynamic thermal modelling methodology that Approved Document O Section 2 names as its alternative to the simplified glazing and free-area route, so it is a required citation for any note about overheating. This page is for the 2026 edition, published July 2026, 39 pages, ISBN 9781912034123, and it is FREE to download at both standard and member rate, unusually for CIBSE. The critical compliance point stated on the page: TM59 (2017) is still the version required for compliance with Part O, and CIBSE recommends TM59 (2026) only for industry best practice while it discusses with the Building Safety Regulator how the updated weather files and new version might be incorporated into the Approved Documents. So a note must not tell a reader that the 2026 edition satisfies Part O. The 2026 update adds a new bedroom overheating criterion based on Loughborough University research, updated ceiling fan modelling presenting fans as an effective passive comfort solution, and mandates that all homes be tested under unconstrained conditions using 2050s weather data. TM59 applies to houses, apartments, sheltered accommodation, care homes, student accommodation, prisons and bedrooms in hotels and hospitals, and covers new dwellings and major refurbishments. The page also records that in 2026 the Climate Change Committee raised risks to buildings and communities from heat to its highest category, Critical Action needed.
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HETAS
The fuel certification scheme behind the legal restriction on what can be burned in a domestic stove or open fire, run by HETAS as one of its Fuel Schemes. Ready to Burn certification is the mechanism by which wood and manufactured solid fuel sold for domestic burning in England is shown to meet the moisture and sulphur limits set in law, so a note telling a reader to buy seasoned logs should point at the Ready to Burn mark rather than at a moisture percentage alone. HETAS also runs installer and business registration schemes, administers schemes on behalf of others, and publishes a searchable approved products database plus householder advice leaflets, so both the fuel and the appliance can be verified from the same body.
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HETAS Limited
HETAS describes itself as a not for profit organisation operating a competent person scheme for installers of biomass and solid fuel heating, together with registration for retailers and chimney sweeps and approval of appliances and fuels. Its site carries searchable registers of registered businesses by postcode or business ID covering retailers, installers, chimney sweeps, servicing engineers and biomass maintenance, plus a separate Removed Business Register for firms no longer registered, and an approved stoves and fuels search. It publishes consumer guidance on choosing a stove, maintenance, and when to have appliances serviced and chimneys swept, and runs Chimney Fire Safety Week, held 7 to 13 September in 2026. HETAS is one of the MHCLG-authorised competent person schemes, so a HETAS registration can be checked rather than taken on trust.
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MCS (Microgeneration Certification Scheme)
How the standards behind MCS certification are set and changed, which matters because MCS certification is a precondition of the main heat pump and solar grants. MCS Standards are owned by the MCS Foundation and governed by the MCS Approval Committee, chaired by the Independent Chair of Standards, David Heath, whose role is to oversee the Technical Working Groups and protect the integrity and impartiality of the Standards. The Approval Committee ensures changes adhere to governance processes and, depending on the type of change, incorporate industry and technical expert feedback through public consultation. Technical Working Groups develop the Standards and many members sit on European committees, keeping MCS aligned with current EN Standards. Two published change processes govern updates: the Technical Document Control Process, reference 455010, for MCS Technical Standards, and the Scheme Document Control Process, reference 184199, for MCS Scheme documents.
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MCS (Microgeneration Certification Scheme) / MCS Charitable Foundation
The installation standard for domestic solar PV, which an installer must hold MCS certification against for the system to qualify for the Smart Export Guarantee. It specifies requirements for MCS contractors undertaking the supply, design, installation, set to work and commissioning of solar PV systems supplying permanent buildings and normally connected in parallel to the electricity distribution network, up to a maximum DC output of 50 kWp. Systems mounted above or integrated into pitched roofs must use products tested and certified to MCS 012 Pitched Roof Installation Kits; where no suitable MCS 012 certified mounting system exists, a non-certified system may be used only on stated conditions, including evidence of how the weather-tightness of the roof is maintained, that existing warranties remain valid, and that quality is no less than an MCS 012 kit would give. It requires that roof brackets fixing a PV system to a slate or tiled roof impose no load on the slates or tiles, echoing section 11.4.1 of the Code of Practice, unless the bracket is certified to MCS 012 clause 7.7.2(b) as distributing load without damage.
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NAPIT
Useful for untangling the terms consumers meet on certification schemes. Distinguishes authorisation, accreditation, certification and registration: NAPIT Registration is authorised by government to operate Competent Person Schemes supporting self-certification against the Building Regulations in England and Wales, with the current scope of that authorisation published on the Government website, while NAPIT Certification is separately accredited by the United Kingdom Accreditation Service, with the schedule of accreditation published on the UKAS website. Explains that a scheme member is normally both registered, meaning listed on a searchable register, and certificated, meaning holding a certificate within the scope of a particular scheme, and that the search facility verifies certification status. Warns that not all work carried out by members is covered by the scheme scope.
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NICEIC
Sets out how self-certification replaces a local authority building control application: a registered contractor does not notify the local authority in advance, but notifies the work online to NICEIC, which issues a building compliance certificate to the customer and tells the local authority the work took place, so building control charges are not payable by the consumer. Covers Building Regulations notification for gas, heating and hot water, ventilation, plumbing and microgeneration, with electrical-only contractors directed to the separate Domestic Installer Scheme. Scheme conditions state that contractors working in domestic dwellings must hold at least 2 million pounds of public liability insurance and must offer clients a warranty for completed work. Published fees are an initial application fee of 95 pounds plus assessment and certification of 595 pounds covering one to four units, with measures priced in units, for example heating or hot water systems 1 unit, sanitary convenience 2 units, solid fuel burning combustion appliance 2 units, and air source heat pumps 2 units.
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OFTEC
OFTEC is the trade association for liquid fuel heating equipment manufacturers and training providers, and it runs competent person schemes approving businesses and technicians for installation and maintenance. Its registrations cover oil heating equipment, solid fuel heating, electrical heating and renewable heating equipment, and it operates alongside Microgeneration Certification, TrustMark and PAS 2030 registrations. Consumers can find an OFTEC registered technician and order building compliance certificates through the site. This is the equivalent of Gas Safe for an oil-fired system, and the route by which oil boiler work is self-certified rather than notified to building control. HVO as a low-carbon liquid fuel is part of its current work.
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UKAS
The body that sits one level above every certification mark a product carries, and the answer to the question of who checks the checkers. UKAS states that it is the National Accreditation Body for the United Kingdom, appointed by government to assess and accredit organisations providing services including certification, testing, inspection, calibration, validation and verification. Its site carries a searchable directory of accredited organisations, an explanation of the difference between accreditation and certification, and an impartiality statement. This matters for the insulation and cladding clusters in particular: a performance claim tested at a UKAS accredited laboratory, or certified by a UKAS accredited certification body such as the BBA or WRAS, sits on a different footing from an in-house test result or a self-declared figure, and the directory lets that be checked rather than assumed.
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Water Regulations Approval Scheme
The searchable directory of approved fittings and materials, organised by four-digit section number, which lets a reader check a specific product before buying. Sections include 0009 to 0046 backflow prevention devices, with the Schedule 2 Section 6.2 device types named in full: Type AB air gap with weir overflow, Type DC pipe interrupter with permanent atmosphere vent, Type BA verifiable reduced pressure zone valve, Type CA non-verifiable disconnector, Type EA verifiable single check valve giving Fluid Category 2 protection, Type EB non-verifiable single check valve for Fluid Category 2, and Types EC and ED double check valve assemblies giving Fluid Category 3 protection. Section 0120 cisterns storing water for domestic purposes references Schedule 2 paragraph 16(4) of the Water Supply (Water Fittings) Regulations 1999 for the essential items a cistern must include.
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WaterRegsUK (Water Regulations Advisory Scheme)
The WaterRegsUK topic page that maps which Schedule 2 paragraphs govern a hot water or heating installation across the three UK regimes, listing paragraphs 17, 18, 20 and 23 as the applicable requirements for England and Wales, Scotland and Northern Ireland. Paragraph 17 is the unvented water heater and expansion requirement, exempting only instantaneous heaters of 15 litres or less; paragraph 18 covers the discharge from a temperature or expansion relief device; paragraph 20 covers vented systems and vent pipe arrangement; paragraph 23 covers water used in a primary circuit. The page's practical points are that unvented systems sometimes need topping up and that doing so must not create a backflow path from the heating circuit to the wholesome supply, which is why a permanently connected filling loop is prohibited by paragraph 24, and that expansion vessels must be installed correctly to remain effective. Use it as the index into the correct paragraph before quoting the regulations at an installer, then read the paragraph itself on legislation.gov.uk.
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AECB (Association for Environment Conscious Building)
The AECB retrofit standard page, and a useful source of real certified-project performance figures rather than manufacturer claims. The standard requires all-round insulation, minimised summer overheating, moisture risk addressed at junctions, and a low carbon heating system, with certifiers trained specifically in moisture and other risks and junctions assessed for moisture. The page lists certified projects with their measured or designed outcomes: Ward Grove, a 1983 to 1992 private house completed 2023, external insulation, triple glazed, MVHR heat recovery ventilation, space heating 37 kWh/m2 per year; Foxlow, a 1900 to 1918 private house completed 2023, wood fibre internal wall insulation, triple glazed, MVHR, space heating 32 kWh/m2 per year and airtightness 1.9 m3/m2.hr; and a Wrexham retrofit of a 1960s house, external insulation, triple glazed, MVHR, space heating 30 kWh/m2 per year. These are the numbers to quote when a note needs a realistic UK deep-retrofit space heating figure. The page also confirms the step-by-step route exists for households retrofitting in phases.
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AECB (Association for Environment Conscious Building)
The AECB CarbonLite family, the main UK alternative to Passivhaus for a homeowner who wants a measurable low-energy target rather than minimum Building Regulations compliance. The page names four standards and three supporting guidance documents: CarbonLite New Build for new domestic and non-domestic projects; CarbonLite Retrofit for individual or multifamily homes and non-domestic buildings; CarbonLite Retrofit Step-by-Step, designed principally for retrofitting individual or multifamily homes in stages rather than in one go; and the Water Standard for water efficiency in domestic and non-domestic projects, plus Daylighting design guidance (with an AECB CarbonLite software tool) and Airtightness guidance. Each standard has its own detailed guidance PDF. Two facts worth citing: AECB set up the Passivhaus Trust in 2010, so the two bodies are related rather than rivals, and AECB CarbonLite certified homes qualify for Ecology Building Society C-Change mortgage discounts of up to 1.50 percent off the standard variable rate, applied for the lifetime of the mortgage on completion of the project, which is a rare concrete financial consequence of a voluntary standard.
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BEAMA
BEAMA is the UK manufacturing trade association for the electrotechnical sector, representing over 200 companies in a sector that supports 90,000 UK jobs, turns over £14 billion a year and exports £5 billion worldwide. Its work covers product safety, performance, energy efficiency, digital innovation and sustainability, and its current programmes include Accelerating Electrification and Achieving Net Zero. It publishes a Market Pulse Report on the UK electrical products supply chain and maintains a guides and publications library, which is the manufacturer-side source for heating controls, consumer units and EV charging infrastructure claims. Treat its output as industry position rather than regulation.
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BSRIA (Building Services Research and Information Association)
BSRIA is UKAS accredited for airtightness testing and this page sets out what a test involves and when it is required, which is the practical detail behind a Part L conversation. It confirms BSRIA is an ATTMA member, UKAS accredited to test to CIBSE TM23, BS EN 13829 and ATTMA TS L1, and that its certificates are recognised by building control. On when testing bites: the page states airtightness testing of new dwellings is mandatory for developments of over two units, that a sample of each dwelling type must be tested and must fall within the air leakage rate stated in that dwelling SAP calculation, and that for developments of one or two units testing is not mandatory but an assumed air leakage rate above the industry norm must be used instead, so it is usually simpler and cheaper for a builder to test and prove a lower rate. It also lists the information needed to plan a test regime: SAP calculation worksheets, floor plans and sections for each dwelling, the regulation or standard being met, site layout and build programme. Diagnostics offered on a failure include infrared thermography and smoke tests to find leakage paths. Note the page still uses the pre-2021 label Part L1A alongside Section 6 of the Scottish Building Standards, so check the current Approved Document L Volume 1 wording before quoting the sampling rule as current.
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HHIC
HHIC is the member organisation for the UK domestic heating and hot water industry, describing its role as driving, supporting and promoting the sustained growth of that sector. It is the body behind the Benchmark commissioning documentation that a heating engineer completes on a boiler installation, and its Resources section carries the industry's technical guidance on installation, commissioning and system water treatment. Use it as the trade-side counterpart to Approved Document L when a note describes what paperwork should be handed over after a boiler or cylinder installation.
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Passivhaus Trust
The UK body page for the Passivhaus standard, and the right citation for a note explaining low-energy standards above Building Regulations. It confirms EnerPHit is the separate, slightly relaxed Passive House Institute standard for RETROFIT projects, used where existing architecture and conservation constraints make full Passivhaus infeasible, which is the distinction most renovation articles blur. The Trust defines eight Passivhaus principles: the five building principles of insulation, airtightness, ventilation, minimised thermal bridging and high-performance windows, plus three principles of approach, namely detailed performance and comfort criteria, accurate design modelling using the Passive House Planning Package (PHPP), and rigorous quality assurance. It states the UK performance gap between designed and in-use energy conservatively results in a 60% increase in space heating demand in residential buildings, and often considerably more in non-residential, whereas Passivhaus buildings on average perform as designed. On claims: a building may reasonably be called a self-declared Passivhaus provided it satisfies all requirements of the standard, but certification must be by a registered Passivhaus Certifier independent of the design team. Caution when citing numbers: the headline criteria table on this page is published as an image and linked PDF rather than as text, so the numeric targets must be taken from the Passive House Institute criteria document itself.
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TrustMark
What a TrustMark registration is actually worth financially, which is the practical difference between it and an unaccredited trader. Under the TrustMark Framework Operating Requirements every Registered Business is expected to provide a minimum of two years of financial protection for completed works in and around the home, covering product warranties and workmanship. The stated purpose is to cover the homeowner if the business ceases trading for any reason, and TrustMark expects the coverage to extend to four things: prepayments such as deposits or other money paid in advance of work, two years post completion of workmanship, rectification of defects or non-compliance with Building Regulations, and major damage or injury through public liability insurance. Cover varies between businesses depending on their financial protection provider, and TrustMark advises obtaining the details of the specific cover from the business before contracting, and satisfying yourself that it covers the particular products or systems being installed.
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Age UK
March 2026 edition, 26 pages. Disabled Facilities Grant: the maximum grant is £30,000, the disabled person must intend to live in the property as their only or main home for at least five years after completion (the grant condition period), applications by or for a disabled adult are means tested unless made by a landlord for a disabled tenant, and the council must decide as soon as reasonably practicable and in any event within six months of the application, in writing and with reasons if refused, appealable through the complaints procedure and then the Local Government and Social Care Ombudsman. Councils may not charge for aids and minor adaptations, defined as costing £1,000 or less. Boiler Upgrade Scheme grants of £2,500 to £7,500 depending on technology, requiring an existing fossil fuel system, with biomass only in rural or off gas grid properties. Council tenants' Right to Repair covers qualifying repairs the authority estimates will cost less than £250 under the Secure Tenants of Local Housing Authorities (Right to Repair) Regulations 1994, with total loss of electric power to be fixed in one working day and a leaking roof in seven working days, and compensation of up to £50 per job if the second contractor also misses the deadline. Awaab's Law phase one took effect 27 October 2025 for emergency hazards and serious damp and mould. Also notes the landlord EPC E cost cap of £3,500 for registering an exemption.
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Asthma + Lung UK
The domestic sources of indoor air pollution and allergens and what removes them. States a carbon monoxide alarm should be sited in the same room as the boiler, cooker or wood burning stove, and that a landlord must fit one in a rented home. For house dust mites, a 60 degree C wash of bedding and soft furnishings kills them. Covers damp and mould, gas cookers and open fires, wood burning stoves, cleaning products, scented candles and air fresheners, pets and pollen as the main household triggers, and what each means for a renovation specification.
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Asthma + Lung UK
What to change in a home to protect the occupant's lungs. Heat the home to at least 18 degrees C in colder months to prevent condensation, damp and mould. Ventilate by opening windows for a couple of minutes through the day, checking outdoor pollution and pollen first where those are triggers, and keep trickle vents, the small openings in a window or door that admit air while the window is shut, open as much as possible. Clean bathroom and kitchen extractor fans regularly so they keep working. Dry washing outside, or in a well aired room, airing cupboard or tumble dryer. Fix leaks and water damage promptly. A dehumidifier helps but can over dry the air and cause coughing, so choose one where the humidity level can be set. On finishes and cleaning products: use sprays and aerosols with a window open, prefer pump sprays over aerosols because aerosols emit more VOCs, look for Air Label certification, and choose unscented products. Notes a GP can write to a landlord where the home is judged harmful to health.
- fair RN-PVE53B
Cadent Gas
The exact trench a homeowner or builder must dig if they take the self-excavation option on a gas alteration, which is how the cost is reduced. Customers may only excavate on their own private land, Cadent excavates public highways, roads and footpaths, and self-excavation is not available to owners of flats, maisonettes or other shared residency buildings. The trench runs from the property wall at the new meter position and terminates 1m from the existing live gas service pipe inside the boundary. Dimensions: depth 425mm (17 inches), width between 200 and 300mm, bottom level and free of sharp or stony material, and in stony ground dig a further 75mm (3 inches) and backfill with fine material such as sand or stone dust to bed the pipe. Separation: gas pipes must be laid a minimum of 300mm (12 inches) from electricity cables and 250mm (10 inches) from other services. Changes of direction must be at 90 degrees with enough room for the bend: minimum bend radius 0.3m for 20mm pipe, 0.4m for 25mm, 0.5m for 32mm and 1.0m for 63mm. Gas marker tape must be laid a minimum of 75mm above the duct during backfill. Safe digging must follow HSE HSG47, Avoiding danger from underground services, and Cadent surveys the site first so no excavation should start before that.
- fair RN-WTQGII
Cadent Gas
The homeowner emergency procedure and who pays. If you smell gas, call the free National Gas Emergency Service on 0800 111 999, available 24 hours; turn the gas off at the meter unless the meter is in a cellar or basement. If a pipeline is struck during digging, even with no apparent leak, move away and keep others away, then call 0800 111 999. Cadent operates a 'make safe' service: attendance to make you and the property safe and to check for leaks is not charged, but any follow-on work by a Gas Safe registered engineer may be. When tracing a reported leak Cadent may enter neighbouring homes or dig the road, may cut off the supply if it is unsafe to leave on, and may not complete the repair in a single day. The National Gas Emergency Service does not deal with boiler or appliance faults, including a frozen condensate pipe that will not thaw, which is a matter for the boiler cover provider or a Gas Safe registered engineer.
- fair RN-VIVGXQ
Cadent Gas
A service alteration is the route for relocating a gas meter, increasing the gas supply, or moving pipework to suit a renovation. The published sequence and its clock: apply online or by phone for a quote; the customer then has up to 90 days to return signed acceptance and pay; on receipt of acceptance Cadent contacts the customer to agree a start date; on average it takes 6 to 8 weeks from payment to carry out the works, with a call the week before to confirm readiness. The quote needs the distance of external pipework from the current to the new meter position, and the distance of internal pipework to reconnect the boiler if Cadent is to do that. Connections 0800 074 5788.
- fair RN-3TYJ5Y
Cadent Gas
States plainly that moving a gas meter yourself is illegal and dangerous, and that the meter and its service pipe are moved together by the gas transporter. For building work such as remodelling or an extension, moving an internal meter and pipe outside is presented as the easier route. Cadent aims to complete work at the property within 6 to 8 weeks of the customer accepting the quote, longer if there are local authority street works restrictions or where the meter is moving from an awkward indoor position. To get a quote the customer must supply the full property address, name and telephone number, the distance of external pipework needed to move the meter from its current to its new position, and the distance of internal pipework needed to reconnect the boiler to the new meter position if Cadent is to reconnect it. Connections Team 0800 074 5788, Monday to Friday.
- fair RN-UGQVV4
Cadent Gas
The household new-connection route. Same commercial clock as an alteration: quote, then up to 90 days to return the signed acceptance with payment, then on average 6 to 8 weeks from payment to carry out the works, with a confirmation call the week before. The key figure needed before applying for a quote is the distance in metres from the intended gas meter position to the property boundary, because the transporter prices the service pipe run from the main in the street to the boundary and then to the meter. Connections line 0800 074 5788.