mmcirvin: (Default)
mmcirvin ([personal profile] mmcirvin) wrote2007-05-09 11:55 pm

Where to save energy

This article about the savings from compact fluorescents is pretty good. It's really about the interaction between all your electrical appliances and the rest of your energy consumption.

The basic message is that electrical appliances heat your home; all the energy you "consume" running appliances and lighting is really converted into heat that gets dumped into your home. If you want to heat your home, this is a side benefit—so reducing your electricity consumption under those circumstances doesn't save as much in fossil fuel consumption, greenhouse gas emissions, energy costs, etc. as you might think, because you'll be running the furnace a little more. It does probably save some, because electric resistive heating is not the most efficient way to heat your house; but less than a naive calculation would imply.

On the other hand, if it's hot and you're running the air conditioner, the analysis turns upside down, and there's a large multiplier attached to any energy savings from more efficient (or less-used) appliances and lighting, because you'll have to work to pump that heat back out of your house. In that case, switching to fluorescents could save you a lot, and reduce your carbon footprint correspondingly.

And in either case, making your home more efficient at retaining the temperature you want is a big, big win.

[identity profile] rimrunner.livejournal.com 2007-05-10 04:35 am (UTC)(link)
When Mr. Darcy was running 14 computers in his home office, our downstairs stayed warm all winter long!

Our insulation sucks. We're getting a new roof next week and the guy roofing says it'll help keep the temp indoors more consistent, but we should also look at our attic crawlspace insulation.

[identity profile] eb-oesch.livejournal.com 2007-05-10 09:16 am (UTC)(link)
A good article, but -- 90% efficiency or better would be more typical for a modern gas furnace. On the other hand, if you only have lights on where you are, then it's spot heating, which could tilt the equation in favor of lightbulb heating. Also, depending on where you are and what temperatures you're willing to put up with, most of the year may indeed be neither heating season nor cooling season.

Aside -- I have wondered whether most per-capita energy use by country statistics typically cited take into account energy consumed by residents on international flights; I assume the answer is no. In fact, a quick glance suggests that many such statistics are merely calculations of total domestic energy consumption divided by population. In Denmark, annual or even more frequent international airplane holidays are routine among those who can afford it, indirectly buying hundreds of dollars in aviation fuel with no gas tax. (The cynical, and somewhat unfair, comment would be that if you give a person a spare dollar, then they'll probably use it to buy a few kilos of carbon dioxide one way or another, and that much of the world's energy virtue comes from being poor. The equally cynical rider would be that if you don't give someone a spare dollar, then they'll find a tree and convert it to pollutants for free, but that's pushing it; except in sparsely populated areas, there are unavoidable limits to that approach.)

There's also that whole thing about the family car (or SUV, in many cases) trip being more fuel efficient (on a miles per gallon per person basis) than virtually any motorized transportation mode except intercity vans and buses, but I'm getting pretty far afield now.

[identity profile] mmcirvin.livejournal.com 2007-05-10 01:53 pm (UTC)(link)
A lot of these assessments of efficiency can change drastically as a result of asking, "Efficient at what?" It seems intuitively strange to say that electric resistive heating isn't efficient, because an electric coil is obviously 100.000% efficient at converting all the electricity consumed within it into heat. But if the question is "how best can I use available energy sources to make my home the right temperature?" the answer can change radically. And then, as you say, if it's "how best can I make the spot where I happen to be the right temperature?" it could change again. Your car is very efficient at hauling people if it's full of people.

It would probably be a significant win on the whole just to stop propping up unprofitable airlines (and most of them are unprofitable) with various subsidies. Of course the ability of ordinary people in First World countries to easily jet around the world is a wonderful thing, but it's costly in many ways. Though I wonder how much air travel is done by vacationers and how much is business travel (much of which, I know from personal experience, can be easily replaced by telecommunication of various sorts if the company paying the full-fare tickets starts feeling the pinch). It seems a shame to ruin people's fun if there are bigger savings to be had by limiting travel that people don't really want to do anyway.

[identity profile] mmcirvin.livejournal.com 2007-05-10 02:00 pm (UTC)(link)
...Though there's also the fact that if business travel went down, those full-fare tickets would no longer be subsidizing discount fares for everyone else, so travel for pleasure would probably also decline as well.

[identity profile] thette.livejournal.com 2007-05-10 09:40 am (UTC)(link)
That depends on what kind of heating you've got.

My parents heat their house by geothermic energy, which is getting more and more common as oil prices go up. Remote heating (often from burning household waste) is pretty much standard.

[identity profile] mmcirvin.livejournal.com 2007-05-10 12:25 pm (UTC)(link)
There are also situations where the heating is of some conventional fossil-fuel-burning type but the controls and incentives are perverse. For instance, in the building where we lived in Arlington, Mass., there was a furnace that was directly below our apartment, whose operation was in no way related to the temperature in our apartment, for which we were not billed (heat is included in rent by state law) and that provided us with much more heat than we needed for most of the year; we'd sometimes have to run wall air conditioners just to make the bedroom bearable. So from the perspective of our behavior, the apartment was effectively in the tropics.

[identity profile] megmimcg.livejournal.com 2007-05-11 04:31 pm (UTC)(link)
Those of us in cooling load dominant climates definitely benefit fom the use of CF bulbs. Personally I prefer the light from the Sylvania CFs - I have found it most closely approximates the light from an incandescent bulb.

[identity profile] mmcirvin.livejournal.com 2007-05-11 11:22 pm (UTC)(link)
Oh, yeah... you're more or less an expert on this subject, aren't you?

[identity profile] sunburn.livejournal.com 2007-05-11 08:50 pm (UTC)(link)
I just replaced a spotlight in my kitchen-- the kind that's inside the ceiling, not a track light. I actually got the bulb from my dad who was replacing his with CF, but the bulb turned out, though still 75W, to be bigger than the previous spot, and apparently brighter. (It's hard to tell, since that part of my kitchen was dark for a week.)

Point being that with superior illumination I can better sort my recycling and avoid setting things on fire, so in this case, the incandescent bulb is pro-planet.