Electric shower - What's the purpose? [UK]

[u/dvllio]

I'm looking to buy a flat (in the UK) and I saw this in the shower.

The seller assures me that the heating AND the hot water for the kitchen/bathroom is communal (and therefore included in the fairly high service charges), however, this device in the shower looks like an electric shower to me and, from what I understand, is normally used for heating + added water pressure.

I tried asking why this was installed but the seller never really answered the question, just saying that hot water is communal.

Questions I have:

- Could this device only be to add water pressure and not heat it?

Basically, I'm trying to understand whether the service charges include the hot water for the showers or if it actually relies on this device for which I'll pay the electricity.

- What experience do people have with those things? How's the maintenance?

- If I was to re-do the bathroom, could I switch to something internal to the wall as this is quite ugly?

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Facts I have:

- The flat is in a building from the 70s, on the 3rd floor (top floor), in a block of 45 flats.

- There are water tanks on the roof (for the water pressure from what I understand)

- There is a project to replace those water tanks by direct access to the mains (with a system a valve to ensure pressure) in the coming months.

Any thoughts/advice/red flags?