By Joe Lynam
BBC World Service business reporter
Time to ditch old lightbulbs?
When you turn the lights on in your home, how often do you consider the wider environmental implications of your actions?
Traditional electric lightbulbs soak up energy and regularly need replacing.
Faced by the threat of global warming, European governments have been imposing increasingly tough measures on the public to try to crack down on energy waste.
Switching to low energy lightbulbs - known as compact fluorescent lamps, or CFLs - is perhaps one of the few practical ways we can help to cut down on energy use.
For years environmental groups have been telling us to buy CFLs, which cost more than traditional bulbs, but last longer.
But every time you use low energy lights, are you actually helping the environment?
Builder and author Jeff Howell, who writes for Britain's Sunday Telegraph and Independent newspapers, does not think so.
"They certainly do use less energy but we are not taking into consideration the amount of energy used in manufacturing them," he says.
"They also contain nasty chemicals and heavy metals, and they are supposed to be disposed of by licensed, environmentally aware, waste recycling plants. People are often not aware of this, and when these bulbs break they are dumped in dustbins and they go to landfill sites or incinerators."
However, the world's largest low energy lightbulb maker, Philips, is proud of its product's green credentials.
Berno Rahman, the Dutch company's European marketing manager, says that only 5% of the total energy used in the lifetime of a CFL bulb occurs during its manufacture.
"Increasing efficiency is always better," he says.
Philips hopes to reduce the heavy metal content in its CFL lightbulbs, but eliminating it altogether is still some way off.
"As far as I know there is no technology available for CFL manufacturing that can get rid of mercury at the moment," Mr Rahman says.
However much energy CFLs save, it is a drop in the ocean compared with the energy consumed by one of the West's great luxuries - air conditioning.
Even in cold northern European countries such as Sweden and the UK, air conditioning is becoming ubiquitous - and demand is growing.
This is something that has got architect Howard Liddell, who advises the Scottish parliament, hot under the collar.
"There was a proposal about seven or eight years ago for the building regulations to have a presumption against air conditioning in the UK and the industry fought against that and the industry won," he says.
Mr Liddell argues that the increased use of air conditioning, particularly in summer, is also leading to much higher fuel bills.
Whenever new green regulations are proposed, governments attempt to find common ground between industry and environmentalists.
But what if the real green answer is that certain industries have to contract - make less glass, produce fewer ventilation units and suchlike.
Would governments bite that bullet in the face of industry pressure?
John Goodhall, of the European Construction Industry Federation, says his members are working hard installing insulation and finding other energy saving solutions.
"As global warming starts to take hold, the need for air conditioning will become that much greater and the problems of insulating buildings will become even more accentuated," he says.
"By one estimate it has been said that if we go on the way we are, and global warming really does accelerate, we shall see much higher temperatures in northern Europe."
"We have buildings that were never designed to accommodate air conditioning, and that may ultimately lead to there being massive demolition projects [for those buildings] because they will eventually become uninhabitable in the summer time."