I work in an early 50s industrial unit which gets very, very cold in winter.
In the lab we have an electric heater which is normally run at three bars during the day. The last person out is meant to switch it back down to one bar before they leave - enough to keep it from being fucking freezing the next day, but low enough not to waste huge amounts of electricity.

Being the last person in yesterday, before I left I cleaned up all the worktops and diligently switched off everything else that needed to be switched off, and then remembered about the heater about two hours after I got home.

I tried to get in earlier today, but I have no key for any of the outer doors and it turns out that they lock them over the weekend. Whoops.

(I might have expected at least one of them to be open as the mixing supervisor often gets in a bit of overtime on Saturday mornings. Not this Saturday though.)

On the plus side, even though the heater will have been running at full power for nearly 65 hours by Monday morning and pissed a load of electricity right up the wall, at least it'll be nice and warm when we come in.
( The Mock TurtIe ™ --- Thinks you are a cunt, on, Sat 23 Mar 2013, 23:45, 1 reply)

To be deeply boring.
Putting the heater on for one hour at 3kW will likley warm the place as much as 1kW*8, and be lots cheaper - saving perhaps 50p/night.
A 7 day timer would pay back really fast, even if you need to get it professionally installed.
(speedevil, Sun 24 Mar 2013, 1:24, closed)