Mobile paraffin heaters work by ‘open combustion’, which means they draw the oxygen required for combustion from the room where they are located. It is therefore always essential to ensure good ventilation and to adhere to the manufacturer’s indications regarding the minimum space volume in which the heater should be used. The new generation of fuels, including Toyotomi Premium Heating Liquids, are virtually free of sulphur and aromatic hydrocarbons to guarantee high quality combustion. However, one should always ensure normal ventilation and a supply of fresh air when using flueless heaters of this type.