[sasmith]

I really would like to write a more articulate reply, but it's late and I'm tired, so I'll leave you with:

I don't believe you.

Portable electric heaters can be incredibly efficient, since they only heat the room in question. I don't know much about building materials, but the article suggested that most heat loss is through windows, so worrying about wood building seems unnecessary.

Water conservation discussion need to be very localized. Lots of places in the US have very low population densities and plenty of water. Conservation is silly in this case. Whether your toilet uses a lot of water or a little, the same amount of poop and same amount of water are going to end up back in the river. Besides all this, toilet flushing and ice in drinks is peanuts compared to agricultural usage. They are little things and do not make a huge difference.

Please site your sources. Here are some of mine:

http://greenliving.lovetoknow.com/Energy_Efficient_Space_Hea...

http://www.toiletabcs.com/toilet-water-conservation.html

http://en.wikipedia.org/wiki/Water_resources

[cromulent]

I had a look through your sources and they convinced me that you were wrong about water conservation. Even if lots of places have low density and plenty of water, there are negative effects.

Surely using as little as necessary, most of the time, is a good policy.

"Per capita residential water use in the United States is more than four times as high as in England and five times as high as in Germany."

http://en.wikipedia.org/wiki/Water_supply_and_sanitation_in_...

There are many conclusions you can take from that, but a common one would be: Many people in the US use more water than necessary.

In terms of buildings, my experience with houses in Australia (almost zero insulation, single glazing) and northern Europe (astonishing volume of insulation, triple glazing standard) also suggests that there is something to think about here.

[ajb]

I'm not sure that this is what jvdh had in mind, but any pure-heating device is by definition 100% inefficient. Any physical device which does work produces heat as well (well eventually. The energy may feed into other processes before it ends up as heat). A 100% efficient device is one that produces work equal to the amount of heat (I think - my thermodynamics is a little rusty). A pure heater produces heat without doing any work whatsoever with the energy. The most efficient heating would be done either by a heat pump (backwards air conditioner), or by doing some work with it.

Your point about heating only the rooms required is quite true, though. portable heaters may be more efficient than other extant kinds of heater. One other disadvantage is that many of them are air heaters, and the human body is more sensitive to radiant heat than air temperature. (It feels a lot better to be warmed by the sun, than to breath warm air).

There are portable radiant heaters, though far less of them around than there used to be. I think people see them as less safe, which I guess they are.

[dspeyer]

An electric heater is inefficient if the electricity was generated inefficiently.

Inefficient: burn methane at a central point running a steam engine generator, dumping tons of waste steam into the air, run the electricity to your house and turn it into heat there.

Efficient: pump methane to your house and burn it there.

More efficient: burn the methane at a central location running a steam engine generator, carry both the steam and the electricity to your house, heating it and running appliances.

The moral: live densely enough that steam pipes are practical.

[jvdh]

My thermodynamics is rusty as well, but from experience I can say that using a central heating system where hot water is pumped through feels a lot better and seems a lot more efficient than an electric heater.

[jerf]

"Water conservation discussion need to be very localized."

I live in Michigan. Tomorrow my car is going into the dealership to be examined to see if the flood it was in last week damaged it in any subtle ways, then it needs to be cleaned up since I wasn't quite able to get it dry enough to avoid it smelling.

This snapshot gives you a reasonably accurate idea of our relationship to water around here. (I'm smart enough to live where it won't flood, unfortunately my work office is built in a flood plain, albeit on stilts so the main office won't flood, I was out to lunch, bit o' rain pops up, bam.)

[jvdh]

I live in the Netherlands, we have an abundance of water here.

The point is not the availability of water, it is the availability of fresh water. Most of the time it takes a lot of work to treat water in such a way that it suitable for consumption. And then there's the waste water processing. You can't just dump your waste water in nature, it has to be processed first, which takes some effort as well.