Sources

UK Government & Regulators

• Ofgem (ofgem.gov.uk) — Energy price cap, electricity and gas wholesale and retail figures. Quarterly cap reviews.
• Department for Energy Security and Net Zero (DESNZ) (gov.uk/desnz) — Boiler Upgrade Scheme rules, Future Homes Standard regulations, heat pump statistics.
• Department for Business and Trade — F-Gas Regulation (gov.uk/government/collections/f-gas) — Refrigerant rules, F-Gas certification requirements.
• HMRC — VAT on energy-saving materials (gov.uk/guidance/the-vat-rates-for-energy-saving-materials) — VAT treatment of heat pump installs.
• Planning Portal England (planningportal.co.uk) — Permitted development criteria, planning application forms and fees.
• Historic England (historicengland.org.uk) — Heat Pumps in Listed Buildings 2024 guidance, conservation officer best practice.
• Historic Environment Scotland (historicenvironment.scot) — Scottish listed building rules.
• Cadw (Wales) (cadw.gov.wales) — Welsh listed building consent process.
• Met Office (metoffice.gov.uk) — UK climate data, regional winter design temperatures, heating season degree-day data.
• Office for National Statistics (ONS) (ons.gov.uk) — Housing stock and tenure data for context.

Industry & Certification Bodies

• MCS Service Company Ltd (MCS) (mcscertified.com) — Installer and equipment certification registry, MCS standards (MIS 3005, MCS 007, MIS 020), heat pump quality framework.
• HIES Consumer Code (hiesscheme.org.uk) — Workmanship cover scheme for renewable energy installs.
• RECC — Renewable Energy Consumer Code (recc.org.uk) — Trading Standards-approved consumer code.
• QANW — Quality Assured National Warranties (qanw.co.uk) — Workmanship and insolvency cover scheme.
• Refcom (refcom.org.uk) — F-Gas company certification body, refrigerant handling competence register.
• Heat Pump Federation (HPF) (heatpumps.org.uk) — UK industry body for heat pump manufacturers and installers.
• NAPIT (napit.org.uk) — Electrical certification body covering heat pump electrical work.
• NICEIC (niceic.com) — Electrical certification body, MCS Heat Pump scheme administrator.

Research & Independent Data

• Building Research Establishment (BRE) (bregroup.com) — Domestic Energy Fact File, U-value reference data, building physics standards.
• Energy Saving Trust (EST) (energysavingtrust.org.uk) — Independent advice and impact data; heat pump field trials.
• Carbon Trust (carbontrust.com) — Carbon factors for electricity and gas.
• UK Heat Pump Field Trial (DESNZ Electrification of Heat Demonstration Project) — Real-world SCOP and running cost data from 742 UK installs.
• British Standards Institution (BSI) — BS EN 12831 heat loss calculation methodology, BS EN 14825 SCOP test standard.

Devolved Nation Grants

• Home Energy Scotland (homeenergyscotland.org) — Scotland-specific grants, interest-free loans, Warmer Homes Scotland.
• Welsh Government — Nest scheme (gov.wales/nest) — Welsh fuel poverty scheme.
• Northern Ireland — NI Sustainable Energy Programme (nidirect.gov.uk/articles/sustainable-energy-programme) — NI-specific heat pump and energy efficiency support.

Manufacturer Technical Data

Used for brand-comparison content. Always cross-referenced against independent test data where available.

• Mitsubishi Electric UK (mitsubishielectric.co.uk/heating) — Ecodan technical sheets, MELCloud documentation
• Vaillant UK (vaillant.co.uk) — aroTHERM Plus specifications, sensoApp technical guide
• Daikin UK (daikin.co.uk) — Altherma 3 technical data, Onecta app documentation
• Grant UK (grantuk.com) — Aerona 290 manuals, MCS test reports
• Samsung UK (samsung.com/uk/heat-pumps) — EHS Mono technical data
• LG UK (lg.com/uk/business/air-source-heat-pumps) — Therma V technical sheets
• Worcester Bosch (worcester-bosch.co.uk) — Compress 7800i specifications
• Panasonic UK (aircon.panasonic.eu) — Aquarea L T-Cap data
• Nibe Energy Systems (nibe.eu/en-gb) — S2125 ASHP specifications
• Sunamp (sunamp.com) — Thermino heat battery technical data
• Tepeo (tepeo.com) — ZEB heat battery specifications

Tariff data sources

• Ofgem default tariff cap announcements (quarterly)
• Octopus Energy tariff pages (octopus.energy) — Cosy, Intelligent Go, Agile
• EDF Energy heat pump tariff pages (edfenergy.com)
• British Gas heat pump tariff pages (britishgas.co.uk)
• OVO Energy heat pump tariff pages (ovoenergy.com)

Author's primary install data

Many figures on this site — particularly real-world SCOP ranges, fault rates, install timelines, noise measurements — come from the author's own service and install records:

• 100+ heat pump installs across the East of England, 2019-2025
• 80+ annual service visits per year, 2022-2025
• Field-measured SCOP via MELCloud, Onecta, sensoApp data exports
• Sound pressure measurements at 1m using calibrated sound level meter (Type 2)
• 14 listed building installs with documented LBC outcomes

These are denoted in articles by phrasing such as "from my own installs", "measured on my customer base", or by attribution to James Thornton as engineer-author. All anonymised — no customer-identifying data is published.

Update cycle

How to verify any figure

If you want to verify a specific claim:

1. Identify the page making the claim (URL)
2. Note the specific figure or rule cited
3. Email contact at heatpumpcalcs.co.uk with the URL and the figure
4. We'll respond within 5 working days with the primary source and our working

If you've found an error, please tell us. Material corrections are made within 7 days and noted on the affected page.

What we don't use as a source

• Brand press releases or marketing claims (unless cross-verified)
• Second-hand blog posts or content farms
• AI-generated content from other sites
• Forums, Reddit, or social media as primary sources (sometimes useful for sentiment, never for figures)
• Tabloid newspaper coverage of energy issues

For our editorial principles and full calculator methodology, see our Methodology page.