I was browsing through some old posts (there are so many here; how do you choose what to read?) and I read about hot water circulating pumps that are supposed to get hot water to the taps quicker.
This sounds very good. In our house the HW goes from the cylinder to the bathroom, then drops into the kitchen, where it goes into the concrete floor and over to the sink. None of it was lagged. I have tried to lag various parts when I have had different floorboards up but obviously the run under the kitchen floor is inaccessible. It takes ages to get hot water to the kitchen sink. One of these pumps might be a good idea.
However, I am unsure how they work. Do you need to run a return pipe? Do they constantly circulate hot water around the house? If so that would be very impractical because surely you would need to plumb the hot water in a ring main, rather than the traditional radial style and have a return pipe? Also wouldn't this be uneconomical because you would constantly be losing heat through the pipe work rather than keeping it in a well insulated cylinder?
Or is it that the pump only comes on when a tap is open and just increases the flow so that the hot water gets there quicker, like a power shower?
Is there a special pump for this purpose and what are they called?