How to heat the extension

[Ineedwineplease]

We have a 1950s property and when we brought it the extension was just basically a coal shed with gardeners loo in it, we've since had it plastered and electricity added just need to add a sink to the loo but it has no heating. The house is heated by gas and the extension is a flat roof one so can get pretty cold! What's the best way to heat it? We don't want to spend a fortune on electricity or adding gas... I was thinking maybe a storage heater? Thanks for any help!

Thermostatic controlled electric radiator. Storage heaters are a bit 1970's.

Yes, agree with what pp said.

Also is there enough height to insulate the ceiling? Would make a big difference.

Energy from electricity currently costs about four times as much as energy from gas.

You say you have gas CH? Look at the cost of extending pipes and adding a long, low radiator.

You should also improve the insulation. Heat loss may be very bad. The walls can be insulated and dry lined, the ceiling can be lined, or, next time it is renewed, insulation included. You can put plastic film over the windows, though it doesn't last long.

I have a feeling your addition never met building regs.