Light bulb waste heat economics.

I calculated the economics of standard vs halogen light bulbs to be a wash from the electricity used by the bulb. Nevertheless I’ve been switching to halogens figuring the 17 watts of heat saved (43 vs 60) would make more of a difference needing to be removed by the air conditioner in the summer than adding to the furnace in the winter. My sister’s the environmental type but she hates CFLs and LEDs as much as I do so she’s trying to get me to switch to halogens too.
Or is the real world difference of 17 watts so small that it’s not a factor in heating / cooling.

halogens are still incandescent, so I’m not sure what either of you expected. They’re more efficient since they can tolerate higher filament temperatures but a little better than shit is still crap.

meanwhile, my folks switched over to mostly LED bulbs and they’ve paid for themselves in 8 months.

No, she isn’t the environmental type.

Halogens are nice because they give out a full spectrum of light. However, they do give off a lot of heat.

A modern gas furnace has an efficiency in the high 90s, while the efficiency of even a CCGT plant is only in the 60% range, much worse for other designs; the cost of electricity is consequently much higher, both for how much you pay per BTU and the environmental impact, therefore it is better for those 17 watts to come from your furnace than from a lightbulb. Of course, in the summer it is doubly so since the A/C runs off of electricity and consequently draws more power to remove waste heat (that said, for a given power input, an A/C can remove several times more heat, so it might only need 5 W extra to remove 17 W of heat, but of course it might be 17 W when generation/transmission losses are factored in).

I don’t really see the hate for CFL/LED bulbs either - there are good ones if you look for the color temperature and CRI; no reason to have to put up with ghastly greenish/bluish light which tells me cheap manufacturing more than anything else (how hard can it be to mix the phosphors, especially with modern RGB phosphors, together in the right proportions, or for white LEDs, add the right amount of yellow phosphor?).

I know, right? The Philips, Sylvania, and Ecosmart (The Home Despot’s house brand) all have LED bulbs which- by my eye- look just fine. As it is, I just picked up a Sylvania “100W” equivalent LED bulb which seems to be at least as bright as promised and the overall color is fine.

Look, incandescent lamps are about 2% efficient at doing their intended job. That’s miserable by any standard. toss the fucking things out.

The only environmental reason I can think of for hating CFL bulbs is the mercury. If disposed of property, this isn’t such a big deal, but we all know that plenty of folks are throwing these in their regular trash without a second thought.

There are lots of people who exaggerate the mercury content and threat in a CFL - I’ve seen warnings that breaking one inside your home means calling out a hazmat team to properly decontaminate the room. That’s BS given the tiny amount of mercury in a single bulb, but some people believe it.

She doesn’t hate CFLs and LEDs because she’s an environmentalist, that’s her one exception to her usual dogma. I didn’t state my reasons initially because I wanted a factual answer rather than start yet anothr debate but I felt I should mention that we do hate them because otherwise someone would suggest we just use them instead questioning whether 17 watts were worth it.

Our reasons are

  1. They emit light in different directions, so can look odd in fixtures or even not put out as much light, and some can’t be used in enclosed fixtures.
  2. You can’t dim them smoothly from 0-100% like an incandescent. If you’re holding down the dimmer constantly, an incandescent will go dim evenly; and LED will stay flat as zero until around 10-20% then shoot up to that brightness, rapidly rise to 100% and then stay flat. I’ve spent $60 each on computer controlled dimmers for every light in my house so I’m not about to swap them out immediately even if they come out with something that works better.
  3. Light quality. I’ve yet to see a CFL that is indistiguishable from Incandescent light, even from across the room. The Phillips LED passes the “I can’t believe it’s not butter” test, where I put an energy saving lamp in one lamp and a standard bulb in another identical lamp and see we can see any difference from afar- I know of course but don’t tell her and she’s immediatly picked out every CFL I’ve tried, including some expensive ones) but the light still seems kind of off. Just try looking at a red sweater underneath it, for example.

Back to the original question, if it makes a difference my furnace is 83% efficient. (I had a 93% one that broke and I lost the battle trying to get the landlord to replace it with another efficient one. I was just wondering if the heat generated by the 17 watt difference was a big enough factor to add to the calculations of straight electricity savings.

The electrical engineer where I used to work was presented with a proposal to convert to dimmable flourescents in the office. He basically went abllistic; said that the technique for dimming flourescents - clip the wave so the peak is the same voltage but becomes a narrower and narrower squar(ish) wave with the same voltage - this would mess up the phase of voltage vs. amps. Since the large office used common neutrals, as people messed with the lights there was the risk of overloading a neutral line until it burne out or started a fire.

In Canada, where house heating is a significant cost, the difference in heating costs with CFLs has been noted. However, a BTU of natural gas from a modern efficient furnace is a lot cheaper than the same from incandescents. An extra BTU of electricity for heating would cost the same (or less) than getting it from lightbulbs. But as pointed out, in air conditioning, the bulbs and the ac are fighting each other.

Bah, you kids and your ugly in-can-descent lightbulbs!

The only kind of lighting that makes things look “right” is a good old-fashioned kerosene lamp, the way God and Rockefeller intended!

Burning coal releases mercury into the atmosphere, so if you use a more efficient light, less mercury gets into the atmosphere. From what I’ve read, switching to CFL causes a net reduction in the amount of mercury released - even if you break the bulb at the end of its life.

I can’t see this being a problem, as long as the peak current stayed the same; i.e., lowering the duty cycle proportionally decreases average current. Maybe they used electronic ballasts, which in any case if not power factor corrected will draw current in narrow spikes with peaks far higher than a resistive load of the same wattage (your method of dimming also wouldn’t do anything until it reached near zero since current only flows at the peak of the AC waveform). A ballast with PFC shouldn’t have a problem with clipped waveforms though, including those from a standard triac dimmer, unless it tried to maintain constant power to the load.

Nah, Kerosene lamps flickr too much.

I am trying to install a gas light out front, though, the problem is I smell gas around it even when it’s not on so I took it out for the time being. I don’t know if gas quick-connectors naturally leak a bit or if there’s a problem.

I will say this, I hate CFLs because it is nearly impossible to find one with 3 properties I want: high lumens, mid to high temperature hue 3500+K and instant on.

The benefit of using lighting waste heat, is it only heats the room you are in, allowing the rest of the house to be kept at a lower temp. So a BTU of site specific lighting heat is worth much more than a BTU of furnace heat. Sure, I can buy an electric supplimental heater, and I probably will, but is that any more efficent?

It’s not the ideal way to heat, but it means I’m not running out to replace my lightbulbs, at least in the den and the computer room.

On the plus size, my 9 lightbulb chandelier in the dining room no longer puts off waves of heat, now that we’ve switched it to CFL.