Wash basin (bowl) and two-handle faucet

I would like to see a calculation of the additional energy costs caused by unnecessarily drawing half a liter of warm water per hand wash into the pipe, and then offset that over 20 years of use against the (estimated) €15 extra cost for a two-handle faucet and the energy costs generated by the computers that were required to discuss this topic here.

I would like to see a calculation of the additional energy costs, ...

Hello everyone, first of all, many thanks for all the replies. I'll summarize.

Kati, we don't need to start the calculation. You're probably right, but this is more about a fundamental attitude of mine regarding energy consumption and newly installed solutions. Still, thanks

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Reducing hot water supply - thanks to ypg: I've already done that, but it's only an emergency solution that should be bypassed with a new bathroom. The desire for the two-handle faucet is NOT the reason for the renovation, just possibly a desired solution if there is no other option.

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Coolstart - many thanks for the tip pagoni2020 - could be a real alternative to the two-handle faucet! I'll reflect on it or ask Hansgrohe

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"It's not the mixers' fault, but the users'..."
Yes nordanney, that's 100% correct. But what is easier: convincing my wife or buying the appropriate faucet
I know my answer! Good that she isn't reading

Steffi33: That's exactly what I was thinking too. Thanks

Thanks again to everyone and best regards Jörg

Let the faucet come out of the wall with two handles. Looks better and solves your problems.

Hello Bookstar,
it's not that easy. For that, I would have to change the pipes in the wall or do a pre-wall installation, which I want to avoid for space reasons. Of course, that would be the nicest solution.
Thanks and regards
Jörg

Reducing the hot water supply - thanks to ypg: I have already done that, but it is only an emergency solution, which should be avoided with a new bathroom. The desire for the two-handle faucet is NOT the reason for the renovation, only possibly a preferred solution if there is no other option.

Reducing hot water is not an emergency solution. It is a common method to control the flow. I rather see your two-handle faucet as an emergency solution. Because it is certainly not contemporary. And when hot water is needed, you waste dozens of liters during mixing and the risk of scalding is very high.

But what is easier: convincing the woman or buying the appropriate fitting

Convincing is ALWAYS better, and here with arguments that arise solely from feasibility.
On the one hand, there is supposed to be a "wish concert," on the other hand, ecology must be applied. Then the "wish concert" has to subordinate itself to ecology, regardless of whether it comes from a woman or a man.
So far, I see more the motto here: saving at all costs!

How about (additional) decentralized hot water heating? Then the woman can wash her hands warm immediately and you cold. I also prefer warm/hot water when washing my hands.