A plug-in device is sold as a thing you plug in. For a good number of homes there is a socket to fit first, and that cost never appears next to the kit. Here is the whole sheet, including the five lines we still cannot fill in.
* Source: DESNZ final stage impact assessment. The full wording is that devices "are currently available from around £400 - £600 or less for an 800W system in Europe, excluding any installation or other ancillary costs".
Because we have not checked, and every site that has filled it in is copying the same handful of numbers around.
In one week we saw UK prices quoted as from £449, typical street prices of £600 to £900, and a claimed sweet spot of £499 to £599. All from sites selling something or earning commission on it. We did not gather any of those figures ourselves, so we do not repeat them, and you should treat them the same way.
The one figure on this site that comes from a document is the government's, and the government was careful: it is European, it is a range, and it excludes installation. We have printed it with all three qualifications attached.
Real receipts from real UK households. Once we have enough, we will publish a range with the date collected and the number of responses behind it, and you will be able to see how thin or thick the evidence is.
If you have bought one, you know something the entire internet is currently guessing at. It takes a minute.
This is the only way this site gets real UK numbers. We will publish ranges once we have enough of them to be worth publishing, with the date they were collected, and we will say how many they are based on. Nobody's details are published and no seller sees your message.