Comments on: Please don’t use incandescent bulbs for heating

By: Chris W

Chris W — Fri, 25 Dec 2009 14:17:17 +0000

New LED traffic lights in North America now need to be replaced because in wet snow they don’t run hot enough to melt the snow off. This is causing accidents (although people should treat it as a 4 way stop instead of plowing through intersections). There are advantages to heat from an incandescent bulb.

By: charadeur

charadeur — Sun, 17 Aug 2008 21:51:39 +0000

People. Many of you are confusing watts with BTUs. Sure 90 watts of a 100 watt bulb goes to heat. But it is very inefficient way to heat your living space. Fist off there is no forced air to distribute that heat. Second hot air rises and because lights are normally higher in the room the heat just goes right up to the ceiling. A 100,000 BTU furnace at 80% efficiency puts out 80,000 BTUs. A 100 Watt light bulb puts out 341 BTUs. That is a drop in the bucket even if you have a way to force that heat out into the room vs. just being wasted at the ceiling. Sorry but it is dumb to think you are saving money by heating your house with light bulbs. Chances are you are making no difference in heat and just wasting the electricity.

By: Mike

Mike — Sun, 30 Mar 2008 01:42:47 +0000

Yes, also passive houses like Robert says above with air-to-air heat exchangers. Insulation…more expensive and more thought involved but much bigger energy savings. In places with low space conditioning needs, lighting starts to play a bigger role and CFL use will have a bigger impact.

By: Mike

Mike — Sun, 30 Mar 2008 01:40:35 +0000

If I can extract a lesson from this whole dialogue it’s that small, measures in the area of energy efficiency SOMETIMES and IN SOME CONTEXTS do not yield the benefits they are supposed to. If we are serious about energy efficiency, it is going to take some more ambitious measures and/or some more context sensitive measures.

If you have low or no-carbon electricity and mostly oil and natural gas heating, it makes sense to start incentivizing the use of electric heat pumps and especially ground source heat pumps. Yes, it is expensive but in the long run if you want to reduce carbon dioxide that is going to do a lot more than CFLs.

By: Robert

Robert — Fri, 28 Mar 2008 10:52:38 +0000

Paul

“Where, in a zero CO2 world, will the energy come from for heating?”

Mostly from insulation and conservation. We were asounded by how much difference it made after we installed cavity wall insulation and 270mm loft insulation. Despite being double glazed the windows are now the main source of heat loss, but in the evenings with the curtains shut we can easily keep the whole (detached) house at around 21 deg C with one fairly small log burner, even when it is -5C outside.

Houses can be built – and are in places like Germany and Sweden – which require no heat. By hyperinsulation and careful heat management there is no need for any form of heating.

By: Paul K

Paul K — Fri, 28 Mar 2008 02:20:07 +0000

Robert,
The quote from the post is by Joe, not from the article. Joe, either because he misread the article or to set up a straw man, was the source of the light bulb heat canard that had no relation to the contents of the article. Joe was not really recommending electric air heaters and those who thought he or the study did were down the garden path. I think you’d agree that CFLs are an interim technology on the way to LEDs. This post has touched on a little discussed question. Where, in a zero CO2 world, will the energy come from for heating?

By: Robert

Robert — Fri, 28 Mar 2008 01:32:02 +0000

Paul – I disagree. There seems to be some sort of disjointed discussion in the early posts about whether it is better to use incandescents, blow heaters or CFLs – on the basis that their waste heat isn’t really waste at all!

The comment in the article didn’t help:

“From either an energy or a CO2 perspective, incandescents are a big loser. If you really like electric resistance heat, buy the best portable forced air heater — it’s is still infinitely better than using an incandescent for heat from a CO2 perspective.”

An electric forced air heater is no more efficient than an incandescent bulb. They both convert 1KWH of electrical energy into 1KWH of heat energy. And both waste about another 3KWH in the power station and transmission lines. The correct strategy is to minimise use of electricity, use it only for those applications where there is no alternative and use the most efficient device available. For light generation that is a CFL, or better still an LED device.

By: Paul K

Paul K — Thu, 27 Mar 2008 23:30:18 +0000

Robert,
Nowhere in the article, the study, this post or comment thread has any anyone said electricity is good for heating.

By: Robert

Robert — Thu, 27 Mar 2008 23:19:08 +0000

The point most posters seemed to miss is that eletricity is a really bad way to generate heat, period. Due to the limitations of the Carnot cycle it is virtually impossible to achieve better than 50% efficiency and in practice much lower.

http://www.eia.doe.gov/ cneaf/ electricity/ page/ co2_report/ co2report.html

“The national average thermal efficiency of power generation from fossil fuels in 1999 was estimated to be 32.54 percent, slightly higher than the previous year’s average of 32.42 percent.”

Factor in transmission losses and you are lucky to get 25% of the original heat from the coal delivered as heat to your house. The argument as to what device you use to convert it is irrelevant as all such devices are 100% efficient (if you can call converting the highest form of energy into the lowest efficient).

As several people pointed out it matters little whether your local source of electricity is hydro or not. It is a fungible commodity so each extra kwh involves burning more coal somewhere (as all the hydo gets used anyway).

Conclusion – use CFLs to light your house. Insulate your house to the highest possible standard then use gas locally if you can’t find something better. We have used a wood burning stove for the last 3 years and don’t use the gas C/H at all.

p.s. Why do we hardy souls in the UK appear to not need A/C whereas everyone in N America thinks its a necessity?

By: Valuethinker

Valuethinker — Thu, 27 Mar 2008 21:59:13 +0000

Paul K

Unclear. Peak waterflow in Quebec is spring, but summer waterflow is pretty good too.

Quebec has a January power peak, not a July one.

Quebec’s grid connections are to New York and New England, primarily.