Why are double-handle taps still installed in households and public washrooms?
I'm wondering why double-handle faucets are still installed in sinks, bathtubs, etc in newer places of dwelling as well as public washrooms. From reading, they appear to be easier to install, but surely this can't be the only reason.
I can understand the uses of double-handle faucets in commercial environments (e.g. restaurants), but at home they are really inconvenient:
- They require either two hands to operate or twice the amount of time when operating them sequentially with one hand.
- They waste a lot of water when you are trying to get a precise temperature (there goes 200 L of water and I still haven't gotten into the shower)
- They provide two points of failure in the case of a leak
- Where labelling is required (e.g. hotels), the labels "H" and "C" aren't easily internationalized, though you could use blue and red
- Teaching children how to use a tap seems generally more difficult with double-handle faucets
In public washrooms, patrons generally just want to wash their hands. In some areas, laws require the water to be a certain temperature, but again, compliance can be achieved by setting the temperature of the water for a mixer tap.
I've seen two designs of mixer taps, where they either go from cold to hot, or there is a default position in the middle and left is hot, right is cold.
Has there been a study on this or are there points that I'm missing from a UX perspective?
For reference purposes:
Double-handle faucet - Two knobs that allow you to control the volume of hot and cold water independently
Mixer tap (single-handle faucet) - One knob that allows you to control the volume of water.