Reliable washers.

[ppppenguin]

Trevor, I think you mean a combi boiler. All modern boilers are condensing. I dislike combi boilers because of the limited flow and inability to sensibly use more than one HW outlet at once. I have a conventional low pressure HW cylinder heated by a condensing gas boiler. I have a powerful shower pump which could be seen as wasteful of hot water. Ruth and I shower very day. Total gas bill per day in summer, to cover DHW and cooking averages about 15p. I'm not worried. Obviously a lot more in winter when I'm heating the house.

Modern cylinders are well insulated. Mine isn't up to current standards but it's not bad. Stored DHW allows the use of high pressure cyclinders (eg Megflow), heatbanks and solar pre-heat. Also essential if using a heatpump to supply DHW.