After many years of all sorts of heating systems tried, last winter I seem to have found the ideal one for me. Remember, for ME, maybe not someone else.
It is a small electric oil filled radiator with a thermostatic control (20 squid from Wilko's), and very soon I will be turning it on, and it won't get switched off until March or April next year.
It takes 3 to 4 days to raise the ambient temperature of my 16x9 insulated shop and all machinery up to around 55 to 60 degs.F.
To me that is a nice winter working temperature and as long as the door isn't left open too long it stays that way.
Once the mass of the machines gets up to temperature, the radiator only comes on for a minute or so each hour, and I noticed that my electricity bill was slightly lower than if I was using a radiant or blower heater, and they would only give local heat for the time you were in the shop, and it was freezing cold when you first went in there. I can now wear t-shirts in the middle of winter, plus I have the feel of nice warm machinery, rather than freezing cold lumps of iron..
One thing you must try to avoid are fuel run heaters, like paraffin (kerosene), as they can sometimes produce large amounts of water vapour when run.
Bogs
Bogs