I’m looking to get some heating into my outhouse, its going to be too costly to put a radiator in there so I’m looking to get ether an electric convection heater or an oil filled heater.

Anyone any ideas which one would be best and most energy efficient

anyone help????

A fan heater is about as good as it gets..quick 3kw when you need it if you are only going in there now and again....insulation will help

Yes. It does depend on what kind of heating you require. Constant heat, or temporary heat.
You can get 2Kw fan heaters that would heat a small room in a matter of minutes. Or small 60-120watt tube heaters that will give you a constant temperature to stop things freezing during the winter months.