Methodology

Every figure on this site is either a published price, a published rule or a calculation you can follow. This page explains each.

Certificate prices

The certificate cost calculator uses price ranges collected in September 2026 from the published price lists of national certificate providers and from quotes listed by NICEIC, NAPIT and Gas Safe registered firms across England. Prices are grouped by property size (bedrooms) and region (London, the South East and East, the rest of England, Wales). The range shown is roughly the middle 80 percent of quotes: a quarter of jobs will be cheaper than the low figure and a quarter dearer than the high figure. Portfolio and bundle discounts are applied as percentages taken from the same price lists.

EPC estimates

The EPC C planner estimates a SAP score from the property's age, type, wall construction, loft insulation, glazing, heating and lighting using the same point model as Retrofit Planner's EPC calculator. It is calibrated against the English Housing Survey distribution of ratings by age band and gets within one band for most homes. It is an estimate, not an assessment: the planner says so, shows a range, and tells you when a real certificate (£60 to £120) would change the answer. Improvement points and costs are typical RdSAP gains and installed prices from the Energy Saving Trust and MCS data.

The £10,000 cost cap

The planner applies the cost cap from the government's January 2026 response on private rented sector energy standards: £10,000 per property, with a 10-year exemption once the cap is spent on recommended measures, and a compliance date of 1 October 2030. Spend counted towards the cap follows the rules on that page. We will update the planner when the regulations are laid.

Yield and cash flow

The yield calculator uses your own price, rent and mortgage figures. Defaults for insurance, maintenance, voids and certificates are national averages from the calculators above and from insurer price data. Tax is modelled for an individual landlord under Section 24 (mortgage interest gives a 20 percent tax credit, not a deduction) at basic and higher rate. It ignores capital allowances, losses carried forward and company structures.

Legal dates

Dates for the Renters' Rights Act, the private rented sector database, Making Tax Digital and the EPC C standard come from GOV.UK, HMRC and the legislation, checked in September 2026. Each page names its source and the date it was checked.

Updates

Prices are reviewed quarterly. Rules are updated when the government publishes a change. If you spot an error, email hello@landlordplanner.co.uk.