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Incandescents could heat your home, in a wildly inefficient way

Image of LED bulb surrounded by many incandescent light bulbs
Yes, incandescent bulbs convert 95% of the electricity they use into heat. But that's no excuse for trying to heat your home with the inefficient lamps, which will cost you plenty in replacement costs and energy use compared to LED lamps.

Shedding some light on what was a tricky Team Power Smart poll question

Posted by Rob Klovance

Other than starting a campfire in your living room, there may not be a more ridiculous way to heat your home than relying on incandescent light bulbs.

This may not be news to most of you out there, but the myth of the "efficient" incandescent bulb persists: the notion that while they may be inefficient for lighting your room, they're useful because the heat they produce cuts down on your heating bills.

We posed just that question in October to Team Power Smart members, who may have been understandably confused by the following poll question in their Member Tool Box:

"Incandescent bulbs convert 95 per cent of their energy into heat. Incandescent bulbs help offset your heating bill by reducing your need to turn up the thermostat. True, False or Don't Know.'

Out of nearly 2,000 votes, 29 per cent voted True,  65 per cent False, and 6 per cent said  Don’t Know.

Well, technically, incandescent bulbs could help offset your heating bill. So those who voted "True" are technically correct. But we'll also give a gold star to those who voted "False," because it was a tricky question.

Take it from a Power Smart expert

"Honestly, this one drives me nuts," says Power Smart engineering team lead Greg Morandini when asked about the incandescent heating myth.

"Incandescent lighting is first and foremost, designed to be a light source," he says. "Yes, it's very inefficient at its main task and as an unfortunate result, waste energy in the form of heat is prevalent, although, relatively useless."

Here’s how Morandini explains it.

Most incandescent lamps are located near the ceiling or behind a cover in a table or pole-type fixture. Those locations don’t allow for efficient distribution of the waste heat they produce – basically, they heat some air nearer to the ceiling than to where the heat might be useful.

"When supplying heat to a space, you typically want that source to be located on an outside wall or under a window, in order to blanket the coldest surface with heat," he says. "This is proper heating design, and allows more effective distribution of heat to combat heat loss through the walls and windows."

He adds that the amount of heat emanating from an incandescent lamp is "quite small" and that its effect on the surrounding area temperature is relatively minor. You’d still need a base heating system.

"In reality, one would not normally leave a light on all night to heat a space, and you wouldn't be guaranteed that this heat energy would impact the heating system thermostat at all," he says.  "On another note, lighting systems are not designed for this purpose and will not last long with the extra hours of usage, so lighting replacement costs will be much higher and will far outpace the energy savings potential."

"The final point," says Morandini,  "is that replacing an incandescent lamp with a more energy-efficient option will make the main function of the lamp, lighting, 75 to 85 per cent better. This energy savings far outstrips any minor benefit that the wasted heat may provide to reducing heating load."

Heating tips that actually work

Morandini was more than happy to offer a few heating tips that will actually make your home more comfortable and save you money.  Here you go.

  • Check that all door and window seals are functional and effective.
  • Seal air gaps in the walls, ceilings, baseboard (wall at floor connection) and any other “envelope penetrations”, such as under your sink, in the space around the pipes going into the wall, with the appropriate sealant.
  • Keep electric baseboard elements clean and straight (vacuum them gently so as not to bend them and be careful, they are sharp)
  • Consider reducing your thermostat settings to 19°C when awake and 16°C when asleep. This could save you about 3 per cent on your space heating costs, for every degree C you reduce your thermostat.
  • If you have old thermostats, consider replacing them with new, electronic version(s). "Set-back"” thermostats allow you to change the temperature when you aren’t there, while "set-point" (manually controlled) units are a digital on/off version, similar to the original dial models.
  • Ensure electric furnaces and heat pumps are regularly serviced, according to manufacturer’s recommendations.
  • Install thermal curtains or blinds, to reduce window/wall heat loss.
  • Add more insulation to your attic/basement if applicable. Consult a professional, and ensure installation is code-compliant.
  • Consider changing older single-pane or double-pane windows or glass doors, to ENERGY STAR®-rated units.

Rob Klovance is managing editor or bchydro.com