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This article was published 5/3/2009 (3093 days ago), so information in it may no longer be current.
Statistics from Manitoba Hydro and local number-crunching from a National Research Council study suggest Winnipeggers might only see 16 to 17 per cent energy savings by switching to compact fluorescent lights (CFLs), even though the bulbs are promoted as increasing energy efficiency much more than that.
That's because CFLs don't throw off the same heat as incandescent bulbs, meaning people who install them turn up the heat in winter.
"The problem is, there are all these cross-effects in a variety of things," said Manitoba Hydro spokesman Glenn Schneider.
CFLs use roughly 75 per cent less electricity than their predecessors, said Schneider, but Manitobans who use them will see overall efficiency improvements of just 16 per cent annually. That's taking into account increased heating in winter, but also the fact that air conditioners can be turned down in summer.
A report last month from B.C. Hydro found the higher heating needs could lead to higher greenhouse-gas emissions, a claim disputed by Manitoba Hydro and some environmental groups.
One University of Manitoba professor broke down the numbers for Winnipeg from a study released last year by the National Research Council.
Physics department head Peter Blunden found using CFLs in Winnipeg could cut energy consumption by 67 per cent, "but that's not the whole story," he said. "The issue is all the heat that's thrown off by the incandescents."
Blunden said factoring in heating and cooling changes, Winnipeggers would end up with energy and cash savings of 17 per cent, similar to Manitoba Hydro's findings. Those who use air conditioners would see savings of around 24 per cent, he said, while cash savings will be a little higher for people who heat with gas instead of electricity.
Last month B.C. Hydro reported the province's emissions could go up as people install compact fluorescents and as a result, use more natural gas to heat their homes. However, environmentalists and even B.C. Hydro staff said the equation was far from simple, arguing energy savings from CFLs outweigh the effects of extra heating.
Schneider dismissed the idea of an emissions boost from the bulbs.
He said even if people in Manitoba use more natural gas as a result of switching to compact fluorescents, the excess electricity will be used elsewhere, as in the United States, where it can displace emission-heavy coal power.
Even if energy savings are lower than expected, people will still save money using the bulbs, he said.
Blunden pointed out that lights make up a tiny portion of a home's energy needs, just three per cent on average.
"We're really talking about a very small slice of the energy pie," he said.