Re: Something they don't teach in Norwegian schools...
No idea about the actual Norwegian energy market but someone upthread mentioned paying 3p/kWh, not the 9p you list. In the UK, 9p is cheap, but it's possible to get down to that level with some types of (business or domestic off-peak) tariff, so that wouldn't make Norway an awful lot cheaper than the UK. This supports your argument.
Against your argument is that it depends when the switch is put in. If it is done at the same time as the lights are wired then it will not cost £80 - £160, it's more likely to cost less than 30 minutes of additional work and £3 worth of parts . Perhaps £15 to £20 in the grand scheme of things?
So at your prices you would recoup the cost of the switch in maybe as little as two years if the light is on for 50% of the time (not counting early deaths which might be caused by all that switching).
M.
(speaking as someone currently spending a lot longer than he should, wiring up his new house and putting all sorts of odd little switches and things in :-)
Biting the hand that feeds IT
