Oh, by the way, while I'm ranting about plumbing (see 18th April)....
A few years ago a European friend chided me about UK plumbing. He said that "over there" all the taps are mixer taps, so you can have whatever temperature of water you want. Why do we Brits persist in having "hot taps" and "cold taps" ?
Well, excu-use me. Mixer taps seem to be becoming more common over here. And I very rarely seem to see anyone operate "both halves" of a mixer tap at the same time to get an intermediate- temperature stream.
Perhaps that's because it doesn't work. For sanitary reasons, the water has to be kept separate... so what you usually get if you turn both halves on is two adjacent streams, one of cold water, and one of scalding water. I've just returned from trying to wash my hands under such a mixer tap, and I could feel both the cold water and the scalding water. Not at all pleasant.
The other drawback is, of course, that it increases the cross-heating effect between the pipes, so when you first turn on the cold tap, it comes out warm, if you've been using hot water recently, so you have to waste more water running it through to cold if you want a drink.
What I don't understand is why people want more than two choices of temperature anyway. I want two temperatures: cold, for making drinks, rinsing things, watering plants, etc; and "as hot as I can bear on my skin", for bathing, showering, washing up, washing my hands, and so on. I want two separate taps, one for each of these.
What's the point of having my hot water hotter than I can bear to put my hands in? It puts the hot water system under more stress, costs more in wasted energy;
If I have my hot water at hand temperature, it's easy to run a bath or wash my hands. A separate hot tap and a cold tap. Those are all I need. No mixer tap. I thank you.