# Sources and how the calculators work

> The government guidance, statistics and analyses behind epccalculator.com, last reviewed 26 October 2026, and how each calculator works.

- Canonical URL: https://epccalculator.com/sources/
- Checked: 2026-10-26

## Official, reviewed 25 October 2026

- [GOV.UK: domestic private rented property, minimum energy efficiency standard, landlord guidance](https://www.gov.uk/guidance/domestic-private-rented-property-minimum-energy-efficiency-standard-landlord-guidance)
- [GOV.UK: Find an energy certificate](https://find-energy-certificate.service.gov.uk/)

## Statistics, reviewed 26 October 2026

- [ONS: Energy efficiency of housing in England and Wales, 2025](https://www.ons.gov.uk/peoplepopulationandcommunity/housing/articles/energyefficiencyofhousinginenglandandwales/2025) (median scores; the ONS has said it is discontinuing this series)
- [English Housing Survey 2024-25: housing quality and energy efficiency](https://assets.publishing.service.gov.uk/media/697a0f35005d288bf850deb2/2024-25_EHS_Headline_Report_on_Housing_Quality_and_Energy_Efficiency.pdf) (share of homes by band, cost to reach C)
- [English Housing Survey 2022-23: energy report](https://www.gov.uk/government/statistics/english-housing-survey-2022-to-2023-energy/english-housing-survey-2022-to-2023-energy-report) (modelled running costs by band)
- [GOV.UK: Find an energy certificate](https://www.gov.uk/find-energy-certificate), [EPCs when buying, selling or renting](https://www.gov.uk/buy-sell-your-home/energy-performance-certificates) and [Get a new energy certificate](https://www.gov.uk/get-new-energy-certificate)

## Official, reviewed 26 October 2026

- [GOV.UK: Improving the energy performance of privately rented homes, government response (21 January 2026)](https://www.gov.uk/government/consultations/improving-the-energy-performance-of-privately-rented-homes-2025-update/outcome/improving-the-energy-performance-of-privately-rented-homes-government-response-html): the 1 October 2030 deadline, £10,000 cap, exemptions, £30,000 fine and the aim of regulations in force in 2027. Status on our pages: confirmed government policy, not yet law.
- [GOV.UK: Boiler Upgrade Scheme, what you can get](https://www.gov.uk/apply-boiler-upgrade-scheme/what-you-can-get) and [eligibility](https://www.gov.uk/apply-boiler-upgrade-scheme/check-if-youre-eligible)

## Analyses of the 2026 announcements (no longer our main source for the 2030 rules)

- [Elmhurst Energy: band C by October 2030 (22 January 2026)](https://www.elmhurstenergy.co.uk/blog/2026/01/22/domestic-private-rented-properties-required-to-meet-epc-band-c-by-october-2030/)
- [Jones Day: EPC C by 2030 (March 2026)](https://www.jonesday.com/en/insights/2026/03/epc-c-by-2030-what-real-estate-investors-need-to-know-about-the-uks-new-minimum-energy-efficiency-standards)
- [Housing Today: EPC reforms moved to the second half of 2027](https://www.housingtoday.co.uk/news/government-delays-epc-reforms-until-2027/5141221.article)

## How the calculators work

- Bands: A 92+, B 81–91, C 69–80, D 55–68, E 39–54, F 21–38, G 1–20.
- Landlord cap: £10,000, or 10% of value under £100,000, minus spending since 1 October 2025.
- Cheapest route: every combination of up to 14 measures is tested; the cheapest that reaches 69 points is shown.
- Payback: (cost − grant) ÷ yearly saving.

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