is it more energy efficient to put an electric heater on a timer or leave it on really low all day?

[ReallyReally]

I know that with central heating it's best to have it on low all day rather than having it on a timer and tat's what I do with my central heating for most of the house; but I have an electric heater in my kitchen extension and despite telling myself I would not have it on very much, we are all freezing and I have spent the last two days turning it on and off till the room warmed up

I can't find any information online about electric heaters apart from storage heaters and it isn't one of those; is it better to have it running really low all day, or having it going up and down a lot?

anyone know the answer?

Depends on the difference in electricity consumption between low and high settings and how long in the day you would use it on each.

For instance if on low it's rated 400kW and on high 1200kW, then it costs three times as much on high than low - if in a 9 hour day you had it on high for more than 3 hours, but off the rest of the time it would cost more than leaving it on low for the whole 9 hours.

You need to find the rating for the different settings (on the instruction leaflet maybe?) and do the sums; or get one of those usage monitors, plug it into that and measure how much is used over a 24h period both ways.

I don't think that's true about central heating, reallyreally. Unless you have a perfectly insulated house.

As snorkle says, it depends on how the thing works. But for example, our oven uses the same amount of power to heat itself up if you're heating to 100 or 200 - it just uses that power for a lot less time. Then it cycles on and off to maintain that temperature, and each time it's on, it uses the same, standard amount of electricity.

So it depends how the thermostat etc. works on your particular radiator.