About EnergySums and our methodology

Independent, regularly updated calculators to help UK households make sense of home energy decisions.

What we do

EnergySums builds free calculators that answer practical money questions about solar panels, batteries, heat pumps, EV charging and energy tariffs. We don't sell or install any equipment. In future we may show clearly labelled adverts and links to installer quote services, which may pay us a referral fee. That will never change a calculator's result, and every such link will be marked.

Where our numbers come from

• Energy prices: the Ofgem price cap, updated each quarter (1 January, 1 April, 1 July and 1 October).
• Grants: GOV.UK and Ofgem guidance on the Boiler Upgrade Scheme.
• Solar yields: rounded regional figures derived from the EU JRC's PVGIS tool.
• Export and smart tariff rates: supplier pages and dated independent comparisons.
• Installation costs and some tariff rates: editorial estimates, clearly labelled as such.

All the figures sit in one public data file with a source link and "last updated" date (currently 2026-10-20).

Who runs EnergySums

EnergySums is run by an independent sole operator based in the UK. You can reach us at hello@energysums.co.uk.

Limitations

Our calculators use averages and simplified models. They can't see your roof, your insulation or your half-hourly usage. Use them to understand the trade-offs and to sense-check quotes, not as a final answer. Nothing on this site is financial advice.

Update log

• 20 October 2026: site launched with the October–December 2026 price cap and BUS rules checked on GOV.UK.