that depends mate oil has gone up a lot and is going up yet again soon. yes mate it just like your oil boiler but a lot smaller pipe goes in the bottom and out the top, then off round your rads. sounds like you will need a 9 or 12 kw boiler mate but that depends on the amount of rads needed to heat up the areas and to what temp ect. if you give me the size of the room and height also wall thickness and insulation if any i will work it out for you so then you will know whats needed in radiator and boiler size