Compact flourescents last about 8 times longer than ordinary globes and use much less energy, though they cost more at first. A 20 Watt compact fluorescent costs $10 to buy and $20 to run over its average life of about 5 years. Over the same time, eight standard incandescent 100 Watt globes would cost $8 to buy and around $103 to run. The fluorescent will have saved $80 and 650kg of greenhouse gas. And you don't have to change the bulbs as often.

Fit lower-wattage globes or compact fluorescents in bright lights, especially downlights and spotlights; save up to 50% of greenhouse gas.

Reflector-back lamps of lower wattage provide more useful light in downlights or spotlights while generating less greenhouse gas.

Low voltage halogen lamps are not necessarily low energy lamps: each one generates one kilogram of greenhouse gas every 15 hours – about the same as an ordinary 60-watt globe – although they do produce more light.

Use light fittings which allow maximum light to pass through – coloured glass often cuts light output by half, creating a need for higher-wattage lamps.

A 20-watt compact fluorescent provides as much light as a 100-watt incandescent.