Methodology

Figures start from published public records: datasets from government agencies, and official pages for things like processing times. A source is only used when its terms allow it to be republished and when you can open the same record and check it.

Every page names its source, the period the data covers and the date it was fetched.

When a figure varies from place to place, the page shows the whole spread instead of a single average. Typical is the middle half of the values: a quarter of places are below it and a quarter are above it. The line inside that band is the median, the value with as many places below it as above.

An average can be pulled a long way by a few extreme places. The middle half is not, so it is a better guide to what most people pay.

Many figures are worked out from a published rate and stated assumptions, such as how many hours a day an appliance runs. These are estimates. Each one is printed with the sum that produced it, and the calculator on the page lets you replace the assumptions with your own numbers.

Public data arrives late. A price published this month often describes a month or two ago. Pages state the period the data describes, and never present it as today's figure.

Each dataset has a limit on how old it may get. When a source is not refreshed in time, its pages are held back from search engines until the data is current again.

• No figure is invented, guessed or generated by AI.
• No page is published for a place unless there is data for that place.
• No answer is hidden behind an ad, a sign-up or a pop-up.
• Advertising never changes a figure or the order of a ranking.