Here's a few simple facts about heaters that work by electricity - they are ALL 100% efficient. That is, they convert all the electricity you pay for into heat - no ifs or buts.
So please forget all this hype about halogen heaters being more efficient to run or costing this or that. IF the halogen heater you are producing to buy only costs 3p per unit to run, it is only going to be rated at an output around 250W - rather less than half the output of a ladies hairdryer. Don't believe the hype.
(Note to the 'experts'. Alright before someone picks me up on it, is of course true that some electric heaters incorporate a fan to blow the air around and this reduces the efficiency to a bit below 100%)