Concerned about the potential environmental impacts of the products it promotes and wishing to keep customers wellinformed, Hydro-Québec asked the International Reference Centre for the Life Cycle of Products, Processes and Services (CIRAIG) to undertake a comparative life cycle assessment of incandescent and compact fluorescent lightbulbs (CFLs). Results For households that heat with electricity The use of energy-efficient CFLs remains the most environmentally sound option at all times, for all the aspects analyzed. For households that heat with natural gas or oil

• Outside of heating season, the use of energy-efficient CFLs is the most environmentally sound option.
• During heating season, incandescent lightbulbs seem to be a better option since they give off heat. However, CFLs remain the best choice for two reasons: the energy savings achieved and, consequently, the potential to use Québec’s clean energy to replace energy from polluting sources.

Mercury in CFLs CFLs pose no significant threat to human health or the environment. The amount of mercury in CFLs is so small (less than 20% of the amount in a watch battery) that waste management accounts for only 1% of the overall environmental impacts in the life cycle. https://www.hydroquebec.com/data/developpement-durable/pdf/ACV-ampoules-resume-de-letude.pdf