Heating, Energy & Eco
274 sources in the library on heating, energy & eco, 40 on this page cited in a published note. 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 1 of 7.
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Building Control Northern Ireland
The index of Northern Ireland's Technical Booklets, the devolved equivalent of England's Approved Documents, and the place to check which NI booklet answers a question. The booklets run B materials and workmanship, C site preparation and resistance to contaminants and moisture, D structure, E fire safety, F1 conservation of fuel and power in dwellings (2022 edition) and F2 for buildings other than dwellings, G sound, H stairs ramps and guarding, J solid waste, K ventilation, L combustion appliances and fuel storage, M physical infrastructure for high speed electronic communications networks, N drainage, P sanitary appliances and unvented hot water storage, R access to and use of buildings, and V glazing. Amendment booklets AMD7 (amends B, C and E), AMD8 (amends R) and AMD9 (amends E and R) carry the live changes, so the base 2012 booklets must be read with them.
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Department for Energy Security and Net Zero
Published 21 January 2026 and last updated 18 March 2026. It commits £15 billion of public investment over this Parliament, 2025/26 to 2029/30, to upgrade up to 5 million homes by 2030, targeting over 450,000 heat pump installations a year by 2030 and solar panels on up to 3 million additional homes. The Boiler Upgrade Scheme gets £2.7 billion to 2030, keeping the £7,500 grant for hydronic heat pumps, adding new £2,500 grants for air-to-air heat pumps and heat batteries used for central heating, and £5,000 for biomass boilers in rural areas. A Warm Homes Fund provides a £5 billion financial transactions facility including £1.7 billion for low and zero-interest consumer loans, rolling out in phases from 2026, and the Warm Homes Social Housing Fund and Local Grant merge into a single low-income scheme from 2027/28. Private rented sector properties must meet EPC Band C across two metrics by October 2030, subject to a £10,000 spending cap, and an EPC C standard is introduced for the social rented sector for the first time. Future Homes Standard regulations were to be laid in Q1 2026.
Cited in Combi vs System vs Regular Boilers.
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Department for Transport
Official DfT statistics that date the scheme change: since 1 April 2022 the Electric Vehicle Homecharge Scheme (EVHS) is no longer open to new applicants and has been replaced with the EV chargepoint grant. The EVHS provided grant funding for up to £350 of the cost of installing electric vehicle charging devices at domestic properties across the UK, and installed 340,222 domestic charging devices from September 2014 with a total grant value of £140.8 million. The EVHS remained open to resubmissions until 31 March 2023. Grant levels quoted for the replacement EV chargepoint grant in this edition: up to £350 per socket for landlords, up to £30,000 for residential car park infrastructure, up to £350 for renters and flat owners, and up to £350 per socket for a cross-pavement charging solution. Useful for correcting notes that date the EVHS closure to 2023.
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Department of Finance (Northern Ireland)
Northern Ireland's equivalent of Approved Document L Volume 1. This edition came into effect on 30 June 2022 and gives guidance on regulations 39 to 47 of the Building Regulations (Northern Ireland) 2012, which set the requirements for conservation of fuel and power in dwellings, including the limiting U-values a replacement window or door must meet in Northern Ireland. It replaced the 2012 version, and the Department publishes an awareness briefing and FAQ setting out the differences. The full text is at https://www.finance-ni.gov.uk/sites/default/files/publications/dfp/TB%20Part%20F1%202022_On-Line%20Publication.pdf. Cite this rather than Approved Document L whenever a note gives a window U-value for a reader in Northern Ireland.
Cited in Insulation: The Complete Guide.
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GOV.UK
The England-only successor to the Home Upgrade Grant, delivered by local councils. Eligibility: household income of £36,000 a year or less (with postcode and benefit-based exceptions), privately owned home, EPC rating D to G. Funds wall, loft and underfloor insulation, air source heat pumps, smart controls and solar panels, with the council organising and paying for the work. Explicitly 'only available in England'. Use this whenever a note says HUG closed and a successor is awaited: it is live and taking applications.
Cited in LPG Conversion Cost: 2026 UK Price Guide.
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GOV.UK
The grant values: £7,500 towards an air source heat pump, £7,500 towards a ground source heat pump including water source heat pumps and those on shared ground loops, and £5,000 towards a biomass boiler. A further £1,500 is available until March 2027 where the property is heated by oil or LPG and has no mains gas connection. Only one grant is available per property. Capacity limits are 45kWth for an individual system, 70kWth for multiple heat pumps and 300kWth for shared ground loops. Hybrid systems pairing a gas boiler with a heat pump are not eligible, and an existing low carbon heating system cannot be replaced under the scheme.
Cited in Air Source Heat Pumps: Cost, Grants & Is It Worth It, Boiler Problems & Common Faults, Boiler Replacement & Central Heating Costs (UK), Boiler Upgrade Scheme & Heating Grants 2026 and 8 more.
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GOV.UK
The current household EV chargepoint grant page. States that you can get 75% off the cost of buying and installing a socket, up to a maximum of £500. Points landlords to a separate application route. The linked eligibility page requires that you live in a flat you own (including shared ownership) or rent a residential property; landlords cannot use this route, and you cannot claim if you rent accommodation where the landlord or homeowner lives. The home must be in the UK with a parking space that is off-street, private and clearly defined, accessible to you at all times, and that you own or have a legal right to. You cannot apply where a chargepoint or charging infrastructure is required by law. The vehicle must be on the list of OZEV-approved electric vehicles, evidenced by registration, a lease of six months or more, work vehicle use of six months or more, or an active order.
Cited in Build Garage Cost: 2026 UK Price Guide, EV Charger Installation at Home: Cost & Rules.
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GOV.UK
Applicant guidance for the Workplace Charging Scheme. States a maximum grant value of £350 per socket, covering up to 75% of the total purchase and installation cost of EV chargepoints inclusive of VAT, and a combined total of 40 sockets across all sites per applicant; applicants claiming fewer than 40 initially may submit further applications up to that limit. Also sets out the minimal financial assistance limit of £315,000 for an enterprise over any period of three fiscal years. As at September 2026 this page still shows £350 while the GOV.UK chargepoint grants collection page shows £500 per socket under the April 2026 rates.
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Health and Safety Executive
HSE's separation distance table for bulk LPG storage vessels, by capacity, giving one distance that applies equally to buildings, boundary, property line and fixed sources of ignition. Single vessel 0.05-0.25 tonnes (typical water capacity 150-500 litres): 2.5 m without a fire wall, 0.3 m with, 1 m between vessels. Over 0.25 to 1.1 tonnes (over 500 to 2,500 litres): 3 m without, 1.5 m with. Over 1.1 to 4 tonnes (over 2,500 to 9,000 litres): 7.5 m without, 4 m with. Points to LP Gas Association COP 1 part 1 for location and spacing and COP 1 part 4 for buried or mounded vessels. The citable substitute for Liquid Gas UK CoP 1, which is paywalled.
Cited in LPG Conversion Cost: 2026 UK Price Guide.
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HM Revenue & Customs
Section 2.1 sets a zero rate of VAT on the installation of energy-saving materials in residential accommodation from 1 May 2023 to 31 March 2027, after which the rate reverts to the 5% reduced rate; section 2.22 extended it to buildings used solely for relevant charitable purposes from 1 February 2024. Section 2.7 lists the qualifying materials: central heating and hot water controls, draught stripping, insulation to walls, floors, ceilings, roofs, lofts and pipes, solar panels, wind turbines, water turbines, ground source heat pumps, air source heat pumps, micro combined heat and power units and wood-fuelled boilers, with water source heat pumps, batteries for energy storage and smart diverters added on 1 February 2024. Section 2.3 is the critical rule for a renovation note: relief applies to an installation service, or materials supplied and installed together, but materials bought without installation stay standard-rated at 20%.
Cited in Builders' Merchants: The Complete UK Guide (2026), Cost of a New Bathroom (Full Breakdown), Hot Water Options for Your Home, How Much Does a New Roof Cost in 2026? (UK) and 4 more.
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Ministry of Housing, Communities and Local Government
The 2022 amendments took effect 1 October 2022 and extended the carbon monoxide alarm provisions. Table 2 sets the minimum flue sizes: 200mm diameter for a fireplace with an opening up to 500mm by 550mm, 125mm diameter for a closed appliance up to 20kW burning smokeless or Clean Air Act compliant fuel, 150mm for other closed appliances up to 30kW and 175mm for those above 30kW and up to 50kW. Diagram 17 gives the flue outlet clearances: at or within 600mm of the ridge the outlet must be at least 600mm above the ridge, elsewhere on a roof it must be at least 2300mm horizontally from the nearest weather surface and either 1000mm above the intersection or as high as the ridge, and it must be 1000mm above the top of any openable rooflight or dormer within 2300mm. Bends must be no more than 45 degrees to the vertical and paragraph 1.49 limits a sweepable flue to four changes of direction.
Cited in Boiler Replacement & Central Heating Costs (UK), Chimney Sweep Cost: 2026 UK Price Guide, Moving Boiler Cost: 2026 UK Price Guide, Splashbacks: Glass, Tile & Stone Options and 1 more.
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Ministry of Housing, Communities and Local Government
The in-force U-value tables a DIY insulation or door note must quote, with the exact numbers. Table 4.2, limiting U-values for new fabric elements in existing dwellings, sets roof 0.15, wall 0.18, floor 0.18, swimming pool basin 0.25, window 1.4 or Window Energy Rating Band B minimum, rooflight 2.2, doors with more than 60 per cent of the internal face glazed 1.4 or Doorset Energy Rating Band C minimum, and other doors 1.4 or Doorset Energy Rating Band B minimum. Table 4.3, for existing elements, gives a roof threshold of 0.35 and an improved value of 0.16, which is the figure a loft insulation note needs: paragraph 4.12 says a retained element whose U-value is higher than the column (a) threshold, for example through a loft or garage conversion, should be upgraded to the column (b) value. Paragraph 4.13 allows a lesser upgrade only where the improved value is not technically or functionally feasible or would not achieve a simple payback of 15 years or less. Paragraph 4.8 requires a replacement element to be no worse than the one it replaces as well as meeting Table 4.2. Paragraph 4.10 gives the heritage exception: where character must be maintained, a centre pane U-value of no more than 1.2 or low-emissivity secondary glazing. Note 9 records that the timber window concession of 1.6 or Band C ended on 14 June 2023. The 2021 edition came into force on 15 June 2022; a 2026 edition exists at https://assets.publishing.service.gov.uk/media/69c122a6cfa346b9d4704a55/ADL1_2026.pdf.
Cited in Adding an Ensuite: Cost, Layout & Plumbing, Adding Porch, All You Need To Know About Double Glazing Repairs, Annexe & Granny Flat: Cost, Planning & Rules and 136 more.
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Ministry of Housing, Communities and Local Government
The 2026 edition takes effect on 24 March 2027 for work not connected with higher-risk building work, and 24 September 2027 where it is, with transitional arrangements in Circular Letter 01/2026. Table 3.1 sets limiting U-values for new dwellings: all roof types 0.16, wall 0.26, floor 0.18, window 1.6, rooflight 2.2, doors 1.6 W per square metre per kelvin, with air permeability 8.0 cubic metres per hour per square metre at 50Pa. Table 3.2 covers new elements in existing dwellings, that is extensions and loft conversions: roof 0.15, wall 0.18, floor 0.18, window 1.4 or Window Energy Rating Band B, rooflight 2.2. Table 3.3 covers upgrading existing elements: a roof with a U-value worse than the 0.35 threshold must be improved to 0.16, and note 2 confirms that for dormer windows the roof figure covers the roof parts and the wall figure the cheeks, while note 3 allows a higher U-value where the standard would limit head room provided the insulation plus air gap is at least the depth of the rafters.
Cited in Insulation: The Complete Guide.
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Ministry of Housing, Communities and Local Government
Supports Part O of Schedule 1 to the Building Regulations 2010 (requirement O1 and regulation 40B); the 2021 edition took effect on 15 June 2022 in England, with transitional relief for work notified before that date and started before 15 June 2023. Critically, paragraph 0.3 limits the guidance to NEW residential buildings only (dwellings, residential institutional and residential other, plus shared communal rooms, common spaces and live/work units), and paragraph 0.7 applies it only to the residential parts of mixed-use buildings. Compliance is by the simplified method (Section 1) or dynamic thermal modelling to CIBSE TM59 (Section 2); the simplified method splits England into a high risk location (urban and some suburban London listed in Appendix C, with guidance for parts of central Manchester) and a moderate risk location (the rest of England). Table 1.1 (cross-ventilated) caps glazing as a percentage of floor area at north 15 high risk / 18 moderate, east 18/18, south 15/15, west 18/11, with the most glazed room capped at north 37/37, east 37/37, south 22/30, west 37/22. Table 1.2 (no cross-ventilation) caps glazing at north 15/18, east 11/18, south 11/15, west 11/11, most glazed room north 26/26, east 18/26, south 11/15, west 18/11.
Cited in Glazed Extensions: The Complete UK Guide, Glazing Explained: U-values, Low-E, Argon & Spacers, Rooflights & Skylights: Materials & Types.
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Ministry of Housing, Communities and Local Government
The landing page for Approved Document J, 2010 edition incorporating 2010, 2013 and 2022 amendments, in force from 1 October 2022. It covers air supply, discharge of combustion products and protection of the building for solid fuel, gas and oil appliances, and the information to be provided for hearths, fireplaces, flues and chimneys. The 2022 amendment extended the provisions and guidance on carbon monoxide alarms. This is the document behind hearth thickness, flue size and clearance-to-combustibles rules for a wood burner or an opened-up fireplace.
Cited in LPG Conversion Cost: 2026 UK Price Guide.
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Ofgem
ECO4 is the fourth phase of the Energy Company Obligation across Great Britain. It applies to measures installed from 1 April 2022 and runs until 31 December 2026 following a nine-month extension; ECO3 closed on 31 March 2022 and ECO4 came into force in July 2022. The scheme places a Home Heating Cost Reduction Obligation on medium and large energy suppliers to promote measures that improve the ability of low-income, fuel-poor and vulnerable households to heat their homes, funding insulation and heating upgrades for both homeowners and tenants. Ofgem also lists the Great British Insulation Scheme as a separate obligation on this page.
Cited in Electric Heating Options Compared, Fan Assisted Radiators Cost: 2026 UK Price Guide, Insulation: The Complete Guide, Insulation Grants 2026: ECO4, GBIS & What You Can Get and 4 more.
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Ofgem
The live source for any running-cost sum in a heating note. For 1 October to 31 December 2026 the direct debit cap is 26.32p per kWh for electricity with a 54.83p daily standing charge, and 7.97p per kWh for gas with a 29.68p daily standing charge, giving a typical annual dual fuel bill of £1,723, a 4% rise on the previous period. Ofgem states these are the average unit rate and standing charge for direct debit customers in England, Scotland and Wales; gas prices include 5% VAT while electricity carried no VAT in this period. The cap is reset every three months, so any note quoting a pence-per-kWh figure should be dated against this page.
Cited in Ceiling Fan Installation Cost: 2026 UK Price Guide, Electric Heating Options Compared, EV Charger Installation at Home: Cost & Rules, Fan Assisted Radiators Cost: 2026 UK Price Guide and 5 more.
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Ofgem
The scheme, formerly known as ECO+, ran from April 2023 to 31 March 2026 and is now closed. It obliged medium and large energy suppliers to deliver measures reducing energy use in the least energy-efficient homes in Great Britain. Eligibility was homes with an EPC rating of D to G in Council Tax bands A to D in England, or A to E in Scotland and Wales, plus low-income and vulnerable households. Unlike ECO4, which funds whole-house packages, GBIS mostly delivered a single insulation measure per home. This is the page to cite when a note has to say a grant route has closed rather than leave a reader chasing it.
Cited in Electric Heating Options Compared, Fan Assisted Radiators Cost: 2026 UK Price Guide, Home Energy Audit: DIY Steps, House Rendering Cost: Whole-House Render Prices (2026) and 9 more.
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Ofgem
The scheme that pays a household for exported solar electricity, and the successor to the Feed-in Tariff. It launched on 1 January 2020 and obliges certain licensed electricity suppliers, the SEG Licensees, to pay small-scale generators for low-carbon electricity exported to the National Grid. Eligible technologies are solar PV, wind, hydro, anaerobic digestion and micro-CHP, at installed capacities up to 5 MW, or up to 50 kW for micro-CHP. Crucially for a payback calculation, Ofgem does not set the rate: SEG Licensees determine the tariff rate, contract length and other terms, the only floor being that a SEG rate must always be above zero. Payments are calculated from export meter readings, so an export meter is a practical precondition. Ofgem publishes the list of current SEG Licensees annually, and advises generators to shop around between them.
Cited in Electric Heating Options Compared.
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Ofgem
Defines the two classes of SEG licensee. A supplier is a Mandatory SEG Licensee if it has at least 150,000 domestic electricity customers as at 31 December of the immediately preceding year, and it cannot opt out of offering SEG payments. A supplier with fewer than 150,000 domestic electricity customers as at the same date is a Voluntary SEG Licensee and may choose to opt in. SEG licensees choose the tariff rate, contract length and some other terms they offer generators, and any SEG tariff rate offered must always be above zero. Useful for correcting the common phrasing 'more than 150,000 customers', which misses both the 'at least' and the 'domestic' qualifiers.
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Ofgem
Ofgem's generator-facing SEG guidance, December 2019. The SEG obligation came into force on 1 January 2020 and follows the Feed-in Tariff scheme, which closed on 31 March 2019. Eligible technologies are AD, hydro, onshore wind and solar PV with a total installed capacity up to 5MW, and micro-CHP up to 50kW. Paragraph 1.12: for PV, wind and micro-CHP installations up to 50kW applicants are asked to demonstrate that the installation and installer are suitably certified, which may be an MCS certificate, but the SEG also recognises other schemes as equivalent to MCS. Paragraph 1.13: without an MCS certificate the installation and installer should be accredited to EN 45011 or EN ISO/IEC 17065:2012. Paragraph 1.17: export must be metered by a meter capable of half-hourly measurement with an export MPAN. Paragraph 1.25: a generator must not be receiving a FIT export tariff while claiming SEG, though FIT generation-only installations can take a SEG export tariff.
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Scottish Government (gov.scot)
Scotland's U-value backstops, which differ from England's Approved Document L and are the numbers to quote for a Scottish reader. Table 6.3 for new dwellings gives area-weighted average maximum U-values in W/m2K of wall 0.22, floor 0.18, roof 0.15, windows, doors and rooflights 1.6, and cavity separating wall 0.2, with individual element values of 0.70 for wall and floor, 0.35 for roof and 3.3 for windows, doors and rooflights. A cavity separating wall can be assigned 0.2 where the cavity has effective perimeter sealing around all exposed edges in line with the insulation layers of abutting elements, and 0.0 where the cavity is also fully filled with a material limiting air movement. Table 6.5 for extensions and conversions is two-column: where the existing dwelling's wall and roof U-values are poorer than 0.7 and 0.25 respectively, wall 0.17, floor 0.15, pitched roof with insulation between ceiling ties or collars 0.11, flat or pitched roof with insulation between rafters or integral 0.13 and windows, doors and rooflights 1.4; where those parameters do not apply the figures relax to 0.22, 0.18, 0.15, 0.18 and 1.6, with individual element values of 0.70, 0.70, 0.35, 0.35 and 3.3. Localised poorer areas such as a meter box must be compensated by the rest of the element and are important for condensation control, while repeating thermal bridges such as timber studs are not treated as individual elements because they are already in the BS EN ISO 6946 calculation.
Cited in Insulation: The Complete Guide.
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The National Archives (legislation.gov.uk)
SI 2021/1467, in force 30 June 2022, extending to England and Wales and Scotland. Regulation 10 requires a relevant charge point to incorporate pre-set default charging hours outside peak hours, with the owner able to accept, remove or change them on first use and at any time afterwards; peak hours are defined in regulation 10(4) as 8am to 11am and 4pm to 10pm on weekdays. The requirement is disapplied where the charge point is sold with a demand side response (DSR) agreement and configured to comply with it. Regulation 11 requires the charge point to operate at each relevant time with a randomised delay of up to 600 seconds, determined to the nearest second, which the owner can cancel; it must also be capable of a randomised delay of up to 1800 seconds, remotely adjustable over a communications network. A relevant time is the point at which electricity would start flowing or the rate of flow would change. Other regulations cover smart functionality (5), supplier interoperability (6), failsafe on loss of communications (7), safety (8), measuring systems (9) and security (Schedule 1).
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The National Archives (legislation.gov.uk), Northern Ireland Statutory Rules
NORTHERN IRELAND, and the part letters mean different things from England, so quoting an England part letter into an NI note is a straight error. The parts are A interpretation and general, B materials and workmanship, C site preparation and resistance to contaminants and moisture, D structure, E fire safety, F conservation of fuel and power, G resistance to the passage of sound, H stairs, ramps, guarding and protection from impact, J solid waste, K ventilation, L combustion appliances and fuel storage systems, N drainage, P sanitary appliances, unvented hot water storage systems and reducing the risk of scalding, R access to and use of buildings, and V glazing. So NI Part D is England's Part A, NI Part E is England's Part B, NI Part F is England's Part L, NI Part K is England's Part F, NI Part L is England's Part J, NI Part N is England's Part H, NI Part P is England's Part G and emphatically NOT electrical safety, NI Part R is England's Part M, and NI Part V is glazing. There is NO part covering electrical safety anywhere in these regulations, so domestic electrical work in Northern Ireland is not notifiable building work as it is under England's and Wales's Part P. Regulation 41 imposes consequential improvements, regulation 42 change of energy status and regulation 43 renovation of thermal elements.
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The National Archives (legislation.gov.uk), UK Statutory Instrument 1999/1148
The exact list of plumbing work that must be notified to the water undertaker, with its consent obtained, before it begins. Regulation 5(1) requires notice, consent not to be unreasonably withheld, and compliance with any conditions. The Table item 4 covers installing: (a) a bath over 230 litres measured to the centre line of overflow; (b) a bidet with ascending spray or flexible hose; (c) a single shower unit of a type specified by the regulator connected directly or indirectly to a supply pipe; (d) a pump or booster drawing more than 12 litres per minute connected directly or indirectly to a supply pipe; (e) reverse osmosis; (f) a water treatment unit producing waste water; (g) an RPZ valve or other device for fluid category 4 or 5; (h) a garden watering system not operated by hand; (i) any water system laid outside a building less than 750mm or more than 1350mm below ground. Item 5 covers construction of a pond or swimming pool over 10,000 litres designed to be replenished by automatic means from a water undertaker's supply. Regulation 5(2) exempts approved contractors for items 2, 4(b) and 4(g).
Cited in Pond Fibreglassing Cost: 2026 UK Price Guide, Rain Shower Price Cost: 2026 UK Price Guide.
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The National Archives (legislation.gov.uk), UK Statutory Instrument 1999/1148
The substantive requirements every water fitting in England, Wales and Northern Ireland must meet, and the source of several hard numbers. Paragraph 25(d) caps a single flush from a WC flushing device at 6 litres (7.5 litres under the transitional wording at paragraph 25 as originally applied). Paragraph 17 requires safety devices on every unvented water heater other than an instantaneous heater of 15 litres capacity or less, and on every secondary coil in a primary system. Paragraph 23(1) requires a temperature relief valve or combined temperature and pressure relief valve on every unvented hot water storage vessel with a capacity greater than 15 litres. Paragraph 5 requires every fitting to withstand an internal pressure of not less than 1.5 times its maximum design pressure. Water efficiency limits are also fixed here: 27 litres per kilogram of washload for domestic horizontal axis washing machines on a standard 60 degrees C cotton cycle, 48 litres per kilogram for washer driers, and 4.5 litres per place setting for domestic dishwashers.
Cited in Outdoor Kitchens: Cost & Planning.
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The National Archives (legislation.gov.uk), UK Statutory Instrument 2015/596, as amended
The permitted development rules for solar panels and heat pumps in England, in their currently amended form, so this is the text to check before saying anything needs planning permission. Class A covers solar PV and solar thermal on domestic premises: the equipment must not protrude more than 0.2 m beyond the plane of a wall or pitched roof slope, must not sit higher than the highest part of the roof excluding chimneys, and on a flat roof must not exceed 0.6 m above the highest part of the roof. Wall mounted equipment is limited to 0.2 m protrusion where the wall abuts a highway and 0.4 m otherwise. It is excluded on a wall fronting a highway in a conservation area or World Heritage Site, on scheduled monuments, and on listed blocks of flats; new plug-in solar provisions bar installation on a wooden wall, balcony or enclosure or on timber clad exterior. Class B covers stand-alone solar, limited to one within the curtilage. Class C is ground source and Class D water source heat pumps. Class G covers air source heat pumps as amended by SI 2025/560 in force 29 May 2025: up to two units on or within the curtilage of a detached dwellinghouse and one otherwise, outdoor compressor unit volume including housing not exceeding 1.5 cubic metres for a dwellinghouse or 0.6 cubic metres for a block of flats, no installation on a pitched roof, and not within 1 metre of the external edge of a flat roof. The same amendment removed the words requiring compliance with the MCS Planning Standards.
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Welsh Government (gov.wales)
WALES. First published 3 April 2017, last updated 7 April 2026. Wales publishes its own Approved Document F, and the page carries the current volume 1 for dwellings (910 KB PDF) and volume 2 for buildings other than dwellings, plus replacement volumes that TAKE EFFECT ON 4 MARCH 2027, the same changeover date as the Welsh Approved Document L and distinct from England's 24 March 2027. Welsh Part F diverged from England's when England issued its 2021 edition alongside Part L and Part O, so extract rates and background ventilator provisions for a Welsh bathroom, kitchen or loft conversion should be taken from this document rather than from England's Approved Document F.
Cited in Trickle Vents & Background Ventilation.
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Welsh Government (gov.wales)
WALES. The Welsh Government publishes its own Approved Documents, and this collection page, last updated 19 June 2025, lists them with their current dates so the right edition can be cited: A structure 3 April 2017, B fire safety 19 June 2025, C site preparation and resistance to contaminants and moisture 3 April 2017, D toxic substances 3 April 2017, E resistance to the passage of sound 13 April 2022, F ventilation 7 April 2026, G sanitation, hot water safety and water efficiency 10 May 2023, H drainage and waste disposal 3 April 2017, J combustion appliances 6 January 2025, K protection from falling 19 March 2025, L conservation of fuel and power 7 April 2026, M access 20 March 2025, N glazing 5 April 2017, O overheating, P electrical safety, Q security and R volumes 1 and 2. Wales still has a live Approved Document N on glazing safety, opening and cleaning, which England withdrew in 2013 when its content moved into Part K, so an England-based note that says Part N no longer exists is wrong for Wales.
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Welsh Government (gov.wales)
WALES. Loft insulation must meet the minimum energy efficiency values in the Welsh Approved Documents, and where that upgrade is not technically or functionally feasible the element must instead be upgraded to the best standard achievable within a simple payback of no greater than 15 years. Installing loft insulation as part of a roof renovation where MORE THAN 25 PER CENT OF THE ROOF is being renewed triggers the full Approved Document standard, the Welsh version of the renovation of a thermal element trigger. The guidance warns against blocking ventilation at the eaves. Read alongside Table 4.1 of the Welsh Approved Document L Volume 1, which sets 0.13 W/m2K for roofs in both new and existing dwellings.
Cited in Insulation: The Complete Guide.
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British Fenestration Rating Council
The BFRC describes itself as the UK's most trusted and widely recognised rating organisation for verifying the energy performance of windows and doors. Its Window Energy Rating runs on a scale from A++ down to E and combines three measured factors rather than one: solar gain, the heat travelling in through a window, counted positive; thermal transmittance or U-value, the heat loss out of a window, counted negative; and air leakage, the uncontrolled air flow out of a window that causes heat loss, also negative. BFRC makes the point that a rating is more comprehensive proof than a single U-value. This matters because Approved Document L Table 4.2 accepts either a 1.4 W/(m2K) U-value or Window Energy Rating Band B for replacement windows, so a reader can meet the standard by either route.
Cited in Replacing Misted Double Glazing Units Cost: 2026 UK Price Guide, Replacing Windows: Process, FENSA & Cost, Windows and Doors: The Complete UK Guide (2026).
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BSI
The standard behind any correct radiator or boiler sizing figure, published 31 July 2017 and current but under review. It gives methods for calculating the design heat load for single rooms, building entities and whole buildings, where design heat load is the heat supply in watts needed to hold the required internal design temperature under design external conditions. The calculation is carried out before heating system components are dimensioned and accounts for multiple heat emission devices in one room, domestic hot water heating power where significant, and how required heating power is split between multiple heat generators. It sits in the EPB standard set as Module M3-3, with PD CEN/TR 12831-2 as the explanatory companion. Cite this when a note says a BTU calculator is a shortcut for a proper room-by-room heat loss calculation.
Cited in Boiler Sizing: What kW Do You Need, Radiator vs Underfloor Heating: Which to Choose.
- strong RN-W6LO6X cited
BSI (British Standards Institution)
STATUS: CURRENT. BS 7593:2019+A1:2024 was published 31 October 2024 and supersedes BS 7593:2019, which is withdrawn. Amendment A1 is dated 30 November 2024 in the NBS index and links the code to the new BS 9593:2024 Assessment for the performance of chemical inhibitors for use in domestic central heating and cooling water systems, test method. The code gives recommendations on best practice for preparing circulating water in open vented or sealed heating and cooling systems in individual domestic premises during initial commissioning or re-commissioning after major remedial work such as a boiler replacement, and on ongoing water treatment. It covers sealed cooling systems, treatment of water to overcome scale and corrosion, cleaning and flushing of systems, and the use of in-line filters. It excludes commercial, municipal and most multiple-residential premises but does apply to individual circuits within multi-unit dwellings. IMPORTANT for citation: the reference book still carries the withdrawn BS 7593:2019 base-edition page; this is the live edition page.
Cited in Powerflushing & System Cleaning.
- strong RN-GZ3QEK cited
Institution of Engineering and Technology
IET FAQ page on Section 722 of BS 7671. States that Regulation 722.531.2.101 requires the charging point to be RCD protected by its own RCD of at least a Type A, having a residual operating current not exceeding 30 mA, and that the requirement attaches to the charging point rather than necessarily the whole final circuit. Notes that in practice the RCD will usually be installed within the charging equipment and advises verifying this with the equipment supplier. Refers on to the IET Code of Practice for Electric Vehicle Charging Equipment Installation. Useful for correcting notes that claim a Type B or Type F RCD is required for domestic EV chargers.
- strong RN-7EPWCE cited
MCS (Microgeneration Certification Scheme) / MCS Charitable Foundation
The design standard an MCS installer must follow, and therefore the standard behind every Boiler Upgrade Scheme heat pump. Issue 2.0 dated 05/12/2025. Microgeneration heat pumps are defined as those with a thermal output not exceeding 45 kWth per MCS 007; multiple units may serve one installation with a total design heat load not exceeding 70 kWth determined in accordance with BS EN 12831-1:2017, provided no single unit exceeds 45 kWth. Heat load calculations must otherwise comply with BS EN 12831-1:2017. The heat pump must provide a minimum of 55 per cent of the calculated heat load with power output rated at 55 degrees C flow temperature. Where a design proposes a flow temperature above 55 degrees C, an alternative design at 55 degrees C or lower must also be provided with the differences explained. For domestic hot water the heat pump must be capable of at least 55 degrees C flow at design conditions, and hot water systems must incorporate a means to prevent bacterial growth. It covers ground, air and water source, vapour compression and thermally driven, monobloc and split units. Expressly excluded are cooling only systems, direct expansion ground loop systems, and heat pumps extracting heat from loft spaces; reversible systems are included but must be designed and optimised for heating.
Cited in Boiler Sizing: What kW Do You Need.
- good RN-176JNC cited
Heating and Hotwater Industry Council
The Benchmark checklist supplied with almost every UK domestic boiler. States that failure to install and commission according to the manufacturer's instructions and complete the checklist will invalidate the warranty, and that the boiler must be registered with the manufacturer within one month of installation. Requires the installer to confirm the system has been flushed and cleaned in accordance with BS 7593 and the boiler manufacturer's instructions, to record which inhibitor was used, and to record whether a primary water system filter is fitted. The annual service record repeats, at every service year, that system inhibitor concentration has been checked and appropriate action taken in accordance with BS 7593 and the boiler manufacturer's instructions, with a footnote that a system inhibitor efficacy test is required on every annual service and is only excusable for an interim visit to a non-water-facing component. Also states the boiler must be serviced at least annually by a competent Gas Safe registered engineer.
Cited in Powerflushing & System Cleaning.
- good RN-SAI6DE cited
Heating and Hotwater Industry Council
HHIC installer guidance, 17 pages, tying Building Regulations to the water treatment standards. States that when installing a new heat generator to an existing hydronic system the system should be flushed and cleaned and an inhibitor added, and names BS 7593:2019+A1:2024 as the current edition. Reproduces Approved Document L Volume 1 paragraph 8.8 verbatim. Describes BS 9593:2024 as the new inhibitor performance test method replacing the NSF (formerly BuildCert) Chemical Inhibitor Approval Scheme standard, tested in three stages for corrosion rate and pitting of metal coupons, scale-forming tendency and effect on non-metallic materials. Lists the A1:2024 changes: reference to BS 9593:2024, the water hardness website address, clarity that an in-line filter does not mean a strainer, and guidance on microbiological growth in low temperature systems below 60 C. States that checking and recording inhibitor levels is mandatory in Benchmark, and that annual service checks cover safety, water quality, inhibitor and system efficiency.
Cited in Powerflushing & System Cleaning.
- supplier figure RN-QSHROZ cited
Boiler Central
Boiler Central publishing its own price guidance for this work. A trade supplier writing about what it charges is evidence of the market rate and not a quotation, and the cost book treats it as one figure among several rather than on its own
Cited in LED Strip Lighting: Uses & Installation.
- supplier figure RN-5NZ1EQ cited
Screwfix
the retail price Screwfix publishes for 1 2 x 15mm white chrome angled l s modern thermostatic radiator valve lockshield, which is the supply figure the cost book records for this item
Cited in How to Restore Radiator, Radiator Valves: TRVs, Lockshields & Smart.
- supplier figure RN-5PFKNL cited
Screwfix
the retail price Screwfix publishes for acova 600mm x 628mm 2009btu white horizontal 2 column radiator, which is the supply figure the cost book records for this item
Cited in Radiator Types: Panel, Column & Designer.