OTTAWA — How many members of Parliament does it take to change a lightbulb?

If New Democrat Paul Dewar gets his way, it'll be 50 per cent plus one.

The Ottawa MP is planning to present private-member's legislation to Parliament in an attempt to effectively phase out the sale and use of incandescent lightbulbs in favour of energy-efficient bulbs, such as compact fluorescents.

Dewar says changing lightbulbs is a simple measure that will make a huge difference to the environment and Canadians' electricity bills -- changing just one bulb will generate up to $50 in energy savings and cut greenhouse emissions by up to half a tonne over the its lifetime.

Incandescent light bulbs use electricity that flows through a filament to create light and about 95 per cent of their energy is wasted as heat; compact fluorescent bulbs use only 20 per cent of the electricity to produce the same amount of light.

A grassroots energy efficiency campaign called Project Porchlight, which is delivering free compact fluorescent bulbs to households in Guelph and Thunder Bay, Ont., and across the Yukon, supports Dewar's initiative, and suggests that a phase-out period will ease the transition.

A study out of Australia, where similar legislation is in the offing, found incandescent lighting represents 12 per cent of greenhouse gas emissions from households, while about 25 per cent is attributable to commercial-sector emissions and another 25 per cent come from emissions associated with public and street lighting.