I bought one of these units home from work yesterday.
Just to give it a go.
I can see the merit in it, sure, but you would have to be wasting a lot of Electricity to make any real savings.
I agree, the majority of customers that I have met, couldn't tell the difference between the TV and the HW Cylinder as far as power consumption goes.
I had a prime example yesterday.
As a Faultsman, during the day I go and see a range of problems, as a representative of the PoCo here.
This lady was screaming at me because of her NZ$500 power account and wanted the problem fixed.
All she could do was whinge and whine about her un-employed son being on the computer all night and using all of her power.
So I told her that a computer does not use anywhere near that amount of Electricity over a month.
I went out to my Faults truck and got my Clamp meter, opened the switch-board and proceeded to find the culprit.
I showed her too, as I checked the current on each Phase wire.
I told her son to start his computer up and then turn it off again.
The meter showed a difference of 200mA.
No problems there.
I then put the tester on a 2.5mm wire and the meter shot up to 12A.
It was marked as a Bedroom point, I asked which bedroom it fed, I was met with a blank stare, but I headed through the house and to the bedrooms and in the second bedroom, there was a flex going out through the window, I asked what that was for.
I went outside and it ran into the glass-house.
The lady then conceded that she used a 2 Bar heater to keep the frost off her plants!.
But she had forgotten to turn it off.
I love having my time wasted.