Energy advice is only as good as the numbers behind it. This page explains where ours come from and how we keep them current.
Where our numbers come from
We use sources in roughly this order:
- Official and regulatory data. Energy regulators, statistics agencies and government programmes, for example Ofgem and GOV.UK in the UK, the U.S. Energy Information Administration, the U.S. Department of Energy and ENERGY STAR in the US, and state regulators such as Victoria’s Essential Services Commission in Australia. For solar yield we use the European Commission’s PVGIS tool.
- Manufacturer documentation. Specification sheets, manuals and warranty terms published by the company that makes the product.
- Independent tests and research. Laboratory tests, field studies and consumer organisations where they exist, clearly attributed.
- Supplier price pages. For energy tariffs we use the supplier’s own published rates, not third-party summaries.
We link to the source next to the figure or in a sources list at the end of the page.
What “last checked” means
When a page says Last checked: [date], someone went back to the sources on that date and confirmed that the key figures still matched. It doesn’t mean every sentence was rewritten, and it doesn’t guarantee that a price or grant hasn’t changed since. If you’re about to spend real money, check the official source we link to.
How we compare products
At the moment our product comparisons are based on published specifications, not on our own hands-on testing. We say this at the top of each comparison. We compare like with like (for example, usable capacity rather than headline capacity, and cycle ratings measured to the same threshold), and we point out where manufacturers measure things differently.
If we test a product ourselves in the future, the page will say so and describe how the test was done. We will never imply testing that didn’t happen.
We don’t publish star ratings, and we don’t accept payment or free products in exchange for coverage.
How the calculators work
Each calculator explains its formula on the same page, so you can check the result by hand. Default values such as electricity prices, gas prices and solar yield come from the sources above, with the source and the date shown next to the value. You can replace any default with your own figure, and your own bill or quote will always be more accurate than a national average.
Where we show energy supplier rates, we take them from each supplier’s own tariff pages and re-check them every week. If a supplier doesn’t publish a rate we can verify, we leave it out rather than estimate it.
The calculators run entirely in your browser. The numbers you type are not sent to us.
Countries and currencies
We write for readers in the US, the UK, Australia, Canada and Europe. Grants, prices and electrical rules differ a lot between them, so each page says which country it applies to. Calculators let you choose your country and currency.
Updates and corrections
We review pages when prices, grants or products change, and we update the “last checked” date when we do. If you think something is wrong or out of date, email info@energysavingdesk.com. We’ll check it, fix it if needed, and note significant corrections on the page.
Safety
Some topics involve mains electricity, gas or work at height. Our guides explain the options, but they are not installation instructions. Electrical and gas work should be done by a qualified, registered professional where your local rules require it.