Which kind of heater suits the space
In a home or office, electric heaters, radiators and fires give clean, controllable heat from a socket or a fixed supply. In big, draughty or high-roofed buildings, warm air from a fan heater or space heater has to fill the whole volume, so infrared often makes more sense for people working in one spot. Outdoors, patio heaters warm a seating area, while marquees and temporary structures suit indirect heaters that keep fumes outside.
Kilowatts for rooms and buildings
As a rough guide, a room with average insulation needs about 1 kilowatt (kW) of heat for every 10 square metres of floor, while a draughty workshop or barn is sized by volume at around 50 watts per cubic metre. Infrared and patio heaters are sized by the patch they need to cover rather than the room, and open doors, high roofs and cold snaps all push the figure up.
Power supplies, fuel and fumes
Portable electric heaters up to about 3 kW plug into a 13 amp socket, while bigger ones need a dedicated supply, often three phase, and any fixed wiring is a job for a qualified electrician. Direct diesel and gas heaters release combustion fumes into the space and need ventilation, and fixed gas appliances are fitted by a Gas Safe registered engineer. Electric heaters waste none of the electricity they use, so thermostats and timers do most to cut running costs.
