I was over at friend, Cliff’s house last night. He showed me his new LED light bulbs. They’re awesome. Nice spectrum, smaller than a regular bulb, plenty of light, no observable strobe effect from the power supply, and IIRC they used only 1.5 Watts. Cool to the touch after being on for hours.
But wait. This is the North. With the low temps this Spring, we’re still heating our homes. Therefore any reduction in the heat output of your lighting and other appliances has to be made up, one for one, by the home heating system. Zero energy savings until we get warmer weather (outdoor lighting is of course exempt from this issue – any reduction in consumption means direct energy savings).
That means there will be maybe 120 days this year in which your ultra efficient indoor lighting pays off anything in this region. Remember that when making your pay-off calculations.
Cliff is in the stage production supply business. He showed me some of the new LED Par cans (stage lighting, in this case also computer [MIDI] controlled). Stage lighting can be brutal on the performers, since even with the biggest, most powerful sound systems, it is the lighting that traditionally used the majority of the electrical power. That’s why you’ve so often seen performers soaked in sweat. We’ve been running the old, hot cans, and then running clusters of fans to try keeping the performers halfway comfortable. With these new LED cans, it’s going to be much, much nicer to be on stage, and we won’t need to have the sometimes difficult to accommodate power requirements in our performance contracts. This particular model also changes color by switching the LEDs, something like the way a color video display uses the different color pixels, which means no more screwing around with color gels.
Technology is wonderful, just so long as we keep the retarded politicians (but I repeat myself) out of our business. Let them shovel shit instead. With some training in shit shoveling, maybe they could be of some small service to humanity. I’ve done it. It can be quite important at times.
Let me understand… are you saying that if I replace a traditional incandescent light that generated heat, with one which does not generate (nearly as much) heat, my heating bill will increase because my furnace needs to compensate for the heat the incandescent produced?
There may be some theoretical truth, but not in practice. Economically it’s far cheaper to burn natural gas compared to electricity to produce heat energy.
If I save $1.00 on electricity from switching to a low wattage consumption light, I’d speculate it’d cost far less than $1.00 for my furnace to generate whatever heat the incandescent may have given off.
This only applies if you assume that the incadecents are heaters as efficient or more efficient than your heating system. I think that is unlikely.
As is so often the case, these things depend on the details of where you live. Here in the PNW, electricity is pretty cheap, but oil isn’t – other places, it’s different. If you are near a coal-fired power plant in the NE, and you heat with oil, electric incandescent bulbs help a lot in winter, and pricey LEDs would be relatively expensive. If you live in CA with high electricity and minimal heating requirements beyond the waste heat from the big screen, computer, and fridge, then an LED will help a lot. Many places, it’s likely near a wash.
Everyone’s mileage will vary, but the concept is a valid one, and I don’t know how anyone who understands jr high school physics could argue with it. Will your furnace use less energy if you run some 100 Watt bulbs in your heated space? Of course. Absolutely. Turn off the bulbs and the furnace will make up the difference. Absolutely. The laws of physics say so. It’s called the Law of Conservation of Energy.
So now you’re talking the differences between energy sources, and the infinite particulars of the losses in this or that system. Speaking strictly in terms of joules, the energy saved here has to be made up there, joule for joule. Ipso Facto. QED.
How you choose to do it is of course your own business. Let’s just stop trying to fool ourselves. The placement of your lighting fixtures, how much heat is leaked into your attic through said fixtures for example, and so on and on, will of course play into the net differences. The bottom line is, if you have 100 Watt bulb fully inside your heated space, it’s a 100 Watt heater. If you knock it down to 1 or two Watts, that’s 98 to 99 Watts more power the furnace has to put out. My furnace is electric, so its efficiency is about the same (very good) as the old light bulb (“globular heater”). But my forced air ducting is under the house (in the crawl space outside the wall and floor insulation) so any losses in the ductwork under the house will be losses I’m NOT experiencing with the light bulb that’s fully enclosed in the heated space. Plus I have to run a fan (also under the house) to extract the heat from the furnace, whereas I don’t need a fan to retrieve the heat from the bulb.
Conservation of energy, as a law of physics, is something to be taken for granted. As you say though, there are, or may be, other variables to be considered, and those variables can go either direction, either plus or minus.
If you were running all LEDs off wind and photovoltaics in a remote area, and you had wood heat or some such, you could possibly use the high efficiency LEDs to help stay off the grid altogether. Lighting fixture design is also very much liberated with LEDs, as you don’t have to worry about the significant heat problems inherent in incandescent systems. More materials and configurations become available to the designer.
There are several benefits to the low power lighting, it’s just that the energy savings can be vastly over-stated, and they are always vastly over-stated when we’re talking regions where home heating is used during a significant portion of the year. And it’s often over-stated for political reasons, as you hear politicians making the claims. QED.
“Let them shovel shit instead.”
They already are; the problem is that they’re shoveling it in our direction.
The one case of significance that Lyle and Rolf did not correctly address is the case where you have a heat pump. In that case you do get greater than 100% efficiency out of your central heating system and the incandescence bulbs “waste” energy in converting it to heat because they only convert it at 100% efficiency (minus the small delta of light that escapes the building).
There’s also the line losses on your way to the house. We are wasting quite a bit of energy getting from the generator to the home (let alone the losses in the generator itself) rather than releasing the energy in the home directly, assuming it is using a gas heater. As Joe says, heat pumps can also complicate the issue, and yeah, resistive heating is probably pretty close to a wash, since the visible energy of a light bulb’s output that can escape through windows is, IIRC, a remarkably small percentage of it’s output.
This guy talks about the issue from a carbon emissions standpoint and actually does the math. Not quite the same thing, but he contradicts the theory as well: http://thinkingforfree.blogspot.com/2009/05/compact-paradox.html
In any case, I don’t think it’s quite as simple as presented. 🙂 I’m surprised that there isn’t a paper or a senior thesis by somebody on this somewhere. Have fun!
Down here in Alabama, the lower heat output is much appreciated where, as I write this, its 10:30AM and fast approaching 90. Heat index will probably hit 100+ before the end of the day….
Ideas on alternate heating methods, transmission losses, etc., are all well and good, and important, but they’re different subjects from; “If you don’t make heat this way, you’ll need to make the same heat some other way”. I don’t know if y’all are conflating, or just bringing up these other issues because they’re interesting and important.
Though the heat pump proposal is compelling.
As for the light lost; the LED’s desired output is going to fly through windows just as easily as the same wavelengths created by incandescents, and in any case, I think we could demonstrate that there we’re talking on the order of a small fraction of a Watt per window in visible light loss. Radiant heat from incandescents verses convection from your heating system may result in some larger, but still small difference, depending on location of your globular heaters relative to windows.
A bit OT but, in a Reuters Oddly Enough story last year, there was a man in Germany getting around the old school light bulb ban, he was importing the bulbs from China and selling them as heat globes… heatball.de
and here in the desert of Arizona, any decrease in heat output reduces the load on the cooling system. probably a wash during the mild winter months but potentially significant in summer.
My main concern isn’t making up the heat lost by not generating it via incandescent bulb (which, in the summer in New Mexico, is really not a problem) but rather the costs of replacing bulbs that blow out due to crappy electricity conformance. The LED lightbulbs on my porch have been running for 6 months straight, now, where they tended to blow every three weeks or so before.
At $30 or $45 a pop for good LED lights, I currently cannot afford to replace all my lights just yet. I’d really appreciate having the incandescents legal, so that LED manufacturers would have a lower-bound pressure point for pushing the price of lights down!
Someday, these lights will be affordable, and they won’t be the migraine-causing hazardous fluorescent lights that are the second-most affordable option. Until then, I’d like to stick with incandescents, thank you very much!
I don’t normally comment on posts more than a couple of days old, but from a theater person’s standpoint, the idea of using LEDs for lighting in place of our existing lights sounds wonderful. I usually work backstage, and when the actors have to do quick costume changes they can be wearing as many as four layers of costume at once. Throw that in with our theater being over 50 years old and a less than efficient cooling system, and put the lights on top of it all, and you have the recipe for some very overheated actors and dancers. Plus, they smell pretty ripe after the first act… If Cliff has a desire to test-drive some products on a stage down in Florida, let me know.