Why patio heaters are bad for the environment.

In 2005, liquid petroleum gas (lpg) patio heaters were estimated to have been responsible for 22.2 ktonnnes of CO2 emissions. This is equivalent to the emissions of 4,526 Range Rovers. Emissions for 2006 were projected to increase by 23% . The proliferation of these devices in restaurants up and down the country indicate that this will not be a unique year but an annual trend. The rate is also likely to increase greatly in the coming year as smoking ban comes into effect. The reason that they are so bad for the environment is that a 13kg bottle oflpg produces 38 kg CO2. Used in a patio heater, it will heat 25m2 ofoutside floor area for about 12 hours but if it is used inside it would last 10 times longer. In other words lpg patio heaters are ten times less efficient than indoor heating. Even worse that the lpg patio heaters are the electric patio heaters which are starting to become popular in restaurants. They produce over 90 times more CO2 compared to using lpg to heat the inside of buildings.
The individual impact of a 2 hour meal under an lpg patio heater is 6kg but every diner is encouraging this needless and conspicuous waste.
Thanks to Chit Chong for this information.