Electric water heating and showers

[DeeEyeAye]

I'm looking at installing an electric instantaneous water heater, as sold by Galaxy, Redring, etc; I've read that you can't plumb these straight into a thermostatic mixer shower (which is a shame cos I just fitted one last year, only to find out my DHW system is cr*p).

So, instead, I'm thinking of fitting a blender valve, and then feeding this to my old-fashioned mixer taps on the bath, for use with a shower-head. The idea is that the water will be delivered at a preset temperature, and in use you just need to turn the hot tap all the way on. If it's too hot, you can dial in some cold too, without this affecting the water heater at all.
Does anybody know if this setup would work?

Yes I could fit an electric shower, but where's the fun in that!

 

[TCCHeating]

Just get an electric shower pal! Or even better find out why your current dhw system is carp and go from there. Not enough info provided but what you are suggesting sounds a bit ludicrous and dangerous to me!

 

[DeeEyeAye]

Oh, OK...
Some background:
- the house is entirely electric, on the 'total control' tarrif which gives me access to cheap rate electricity on demand, so long as it's used for heating (including showers, DHW, etc).
- currently there is a tiny tank in the loft which runs pretty hot, and heats up at various times through the day with no user input. Well, I can boost it, or switch it off completely.
- my bills are pretty large and I blame the tank- it's sitting there roasting hot most of the time. There are only two of us in the house and we work odd/unpredictable hours, so it makes no sense to have a tank of hot water sitting waiting, when we can heat water on demand at lower overall cost.

My plan is to simply switch off the current system, maybe putting it back on when we have people staying, and use an on-demand system for the shower. Yes I will have to use a kettle to do the dishes, so what.

I know the easy option is to put in an electric shower, but I'm trying to work out a way that avoid this. The gravity-fed TM shower is only a year old and looks the part. The wife doesn't want me to rip it out and put in an ugly plastic box in the corner.


Since I made that first post, btw, I found suggestions that you can't actually use a blender downstream of a water heater. So now I'm thinking of switching to one of Stiebel Eltron's heaters, which allow you to specify a temperature of as low as 38deg. Shame they are a lot more expensive.