About Retrofit Planner

We build free, independent tools to help UK homeowners make informed decisions about home energy improvements. No sales pitch, no hidden agenda, just clear data and honest calculations.

Why we built this

Millions of UK homes will upgrade their heating and insulation over the next decade. Heat pumps, insulation, solar panels, EPC improvements: there is a lot to weigh up, and the information is scattered across government websites, trade body publications and installer marketing pages.

We built Retrofit Planner to bring that information together into simple, interactive tools. Instead of piecing figures together from reports and sales pages, you answer a few questions about your home and get an estimate in seconds, with the source behind every number. Instead of visiting several government websites to check grant eligibility, you use one checker that covers the main schemes.

Where our data comes from

Every calculation on this site starts from published UK data. Where we have to make an assumption, such as the price of LPG or how heat pump efficiency varies with insulation, the methodology says so. Our main sources are:

• Ofgem: gas and electricity prices from the quarterly price cap, and typical household consumption. We update our calculators when Ofgem announces each new cap.
• BoilerJuice: the UK average price of heating oil, which we convert to pence per kWh with the DESNZ conversion factors.
• Department for Energy Security and Net Zero (DESNZ): the National Energy Efficiency Data-Framework, which gives the gas use of 39,502 homes behind our heat demand model and the savings measured after insulation; the Boiler Upgrade Scheme statistics, which give the installed cost of 30,590 heat pumps; the Electrification of Heat trial, which measured the efficiency of 428 heat pumps in real homes; and the Boiler Upgrade Scheme business case, which puts the average new gas boiler at about £3,500 including VAT.
• Energy Saving Trust: typical installed costs for insulation, and practical advice on each measure.
• MCS: the look-up tables for how much of their own solar electricity households use, and the certification we require of every heat pump and solar installer we pass a request to.
• PVGIS (European Commission Joint Research Centre): solar generation by location and roof direction.
• GOV.UK: grant scheme rules, eligibility and deadlines for the Boiler Upgrade Scheme, ECO4, the Warm Homes: Local Grant and other programmes.

For full details on how we use each data source, see our methodology page.

How we make money

Every calculator and guide is free, with no sign-up and no advertising. A few links earn us a commission, currently a link for booking an EPC online, a link for buying loft insulation rolls and a link for a dehumidifier, and each is marked as paid just before it. Quote requests are paused while we set up installer partners. When they return, a request will go only to the partners named on the form, only with your agreement, and they may pay us a fee for the introduction. Neither a commission nor a fee ever changes any figure on this site, and our calculators still tell you when an upgrade does not pay for itself.

Landlord Planner (landlordplanner.co.uk) is our sister site for private landlords in England, built the same way: free calculators and guides on EPC rules, licensing, tax and the Renters' Rights Act.

Our calculator results are never influenced by anyone. The numbers come from the published sources listed above, the calculations run entirely in your browser, and nothing is adjusted to favour any installer, product or outcome.

Our calculators

We currently offer the following free tools, with more in development:

• Retrofit Plan: the order to do the work in, with the cost, saving and payback of each step
• Heat Pump Cost Calculator: installed cost, grant, running costs against your current heating, payback
• Insulation Savings Calculator: savings by insulation type, costs, grant eligibility
• EPC Improvement Planner: cheapest path to a better EPC rating
• Solar Panel Cost Calculator: generation, savings, and payback
• Boiler vs Heat Pump Comparison: 15 year cost comparison
• Grant Eligibility Checker: which of the main energy grants you could get

Contact

Have a question, suggestion, or spotted an error in our calculations? We'd love to hear from you. Email us at hello@retrofitplanner.co.uk.

If you're a journalist or researcher and would like to reference our data or tools, please see our methodology page for details on our data sources and calculation methods.