svenska84 wrote:Most water heaters I'm familiar with here keep water heated in a large upright cylindrical tank.
Yes, that is what I have too in my apartment. Though it's in the bathroom.
Here in apartments (I don't know about houses, there must be a 1000 ways to heat water there), there are usually two ways. In some buildings (in my town, in those who are considered more elite), hot water is provided by the company that provides central heating. I'm not sure if they have it 24/7, or only during certain part of the day, but it happens that it's not there when it's supposed to be. (judging by the constant complaints.
The other way is what I have: an electric boiler. Mine is right above the bathtub. Since electricity is expensive, it's not turned on constantly, only during the night when the electricity is 4 times cheaper. (It has a mechanism to turn itself on when the 'cheaper electricity' comes) It accumulates water, make it hot and it stays there to be used during the following day. But since the other members of my household are irrational when it comes to spending water, it's mostly gone by 3 pm, so I have to turn it on in the afternoon too.
Mine is cyllinder, but it doesn't need to be. In fact, most modern ones are in the shape of a cuboid. It doesn't even have to be white.
In apartments where the kitchen is separated from the bathroom, I saw a separate mini-boiler for the kitchen sink.
When I was in Alicante, it was a completely another story. Both the hot water boiler and stove used gas, but the funny thing is I didn't know that till I was suddenly out of hot water during the shower (I hate cold water!!!). Since I didn't see any boiler around, I guessed that the hot water is provided externally, and that it must be out of order or something. But then I asked my flatmate about it, and I found out that it uses gas. I must say I was shocked at first, but I got used to that.
(I didn't have much choice)
There were two gas container on the balcony: one for the hot water, one for the stove. They looked more or less like this: http://www.jaimesanchezmontes.com/Img0002.jpg
I just needed to take the empty container down to the pub near my building, and come back with a filled up one.