I have used both gas & paraffin in the past but prefer electric because it is easier to control.

THis is my set up;

http://www.thegardenersalmanac.co.uk...20Set%20up.htm

Click on images to enlarge.

I rarely use my fan heater, it has to be exceptionally cold for me to use this.

I find my thermostatically controlled heated propagator and hot bed very economical to run.

I now have a wireless thermometer/ barometer fitted i.e. control panel is in house and the sensor is in the greenhouse now I can monitor whats happening in my greenhouse from the comfort of my house.

In the event that it gets exceptionally cold, and I have stuff in need of protection I nip up the yard and switch my fan heater on.

It has only been on about four or five times this winter.

I hope this helps!