Posts Tagged ‘Physiology’

Danger, Will Robinson?

February 20, 2010

I provided a little interview material for a recent article over at diylife.com, which has garnered quite a few comments.  The most amusing of them was a guy who accused us of doing this only to save money in order to spend it on drinking more beer (which is funny, because we’ve actually been drinking less beer this winter.)  But here is an interesting comment thread:

“Autumn said… I think this is a bad idea. You could go to sleep one night and not wake up due to freezing to death. I have lived without heat before because of frozen pipes so I know you can get comfortable enough with warm clothing and lots of blankets but I think this is a dangerous thing to try.

Kelly said… Who ever froze to death at 52 degrees?

Justin said… It’s called hypothermia..and you only need your body temperature to drop to 95 degrees before it may not be able to be reversed. You may very well go to sleep and not wake up. Temperatures need not be below freezing for this to happen.”

This did get me thinking (after I stopped laughing, of course):  Is it likely, or even possible, that one could go to sleep euthermic, become hypothermic while sleeping, and perish without waking?

I’ve done a lot of outdoor activities in cold weather.  I have been mildly hypothermic, have been with people who were considerably hypothermic, and have known people who have died of hypothermia.  So I don’t take the topic lightly. Certainly it can and does happen that people become hypothermic, fall asleep / lose consciousness, and never wake up.  If you are already actively hypothermic, and your house (or igloo, or snow cave) is cold, I don’t suggest going to sleep.   I suggest staying awake and trying to get warm.

But my experience says (and a bit of research confirms) that an otherwise healthy person cannot go to bed warm-enough and then just die of cold in his sleep.  If you’re okay when you go to sleep, but start to get too chilly while sleeping, the first thing that happens is: you wake up, feeling cold!– so that your brain can do something about the situation before it’s too late.  Well before your brain becomes addled by cold, your body will start shivering violently enough to awaken you.  Indeed, if you’re feeling rather too chilly (but not seriously hypothermic), it’s pretty hard to get to sleep in the first place– which is a protective mechanism.

The fatal sleep that drags over hypothermic people after their body temperatures have dropped so low that their brains no longer function properly is a whole different story that unravels after your body’s defense mechanisms are exhausted.  But if you go to sleep not-hypothermic, you will not just drift off into hypothermia and perish without waking up and having a chance to do something about your situation first.

Gender, Thermostats: Poll

January 29, 2010

Conversation this morning (house temp 45º):

J:  When are you going to the office?

Me:  Not– working from home today.

J:  Great!  Then you can light a fire!

Me:  Hm, maybe.  Why, when are you going to class?

J:  In an hour.

Me:  Well, that’s not enough time for it to warm up in here anyway.

J:  Oh, pleeeease just promise me it will be in the 50’s by the time I get home tonight!

I think people reading these pages picture J. and I in perfect harmony about this cold-house thing, but that’s a phony image. Like couples everywhere, we bicker a bit about the temperature in the house.  True, the “set point” around which we bicker may be 10 or 15 degrees lower than “normal”, but the process is recognizably similar.  I’m to the point where 48-50º is fine for protracted periods.  I’ll let J. speak for herself, but my guess is that she’d choose 5-10º higher.  Please note that this still makes her an exceptionally good sport, in my book.

The stereotype, of course, is that men like/tolerate colder (or as we call it, “more normal”) house temperatures than women. People have written news stories on the topic, and the Times (UK) asserts there are physiological underpinnings.  Certainly among the couples I know with widely divergent temperature preferences, it is the man who likes it colder– but it’s not a large sample size.  So I’m interested in feedback from readers as to whether this is just a sexist stereotype, or whether there is something to it.  In your house, who likes it warmer?  By how much?  And a potentially illuminating question– do same-sex couples and have just as much disagreement about the thermostat as different-sex couples?

Also (assuming there is any basis to this all to begin with), is it that women prefer it warmer per se, or that they have a narrower range of comfort?  For example, in hot places– where the question is A/C instead  of heat– do men still prefer it cooler, or does the disagreement reverse, with women wanting to turn the A/C down to 68, but men wanting it at 74??

[Addendum:  I managed to titrate the fire so that it was 50.2º when J. got home.  I am a man of my word.  But I’m not sure she was entirely amused.]

Tentative End Plans

December 30, 2008

The Cold House Project is, technically, coming to an end soon. My new housemate has arrived. She is not thrilled with the whole experiment. To be fair, it’s hard to expect anyone would be, unless they were in on it from the start and had the benefit of gradually becoming accustomed to both the cool temperatures and the various little habits of heat maintenance that have, for me, become routine.

She’s an open-minded and environmentally-aware person, and has been a good sport about trying it out for a few days, which is more than most people would do. I’m grateful. But, she’d really like to turn on the heat soon. So, we agreed that it will happen January 1st. That gives me a few days to start adjusting back…

I have to say, though, I’d really rather not. The first couple weeks of this, back in the fall, were a bit challenging– but now I am very happy and comfortable. People find this hard to believe; most everyone assumes I am cold, suffering, and undergoing some sort of ascetic/self-flagellatory experience. Not so. The point was not masochism; it was to find out if there is some mental or physical mechanism that kicks in to make cold temperatures feel comfortable. Answer: there definitely is.

People’s reactions to this experiment have been remarkable. Just hearing about it seems to make others uneasy. I’ve been called un-American, unethical, unbalanced, and even potentially criminal. People have told me that I will get pneumonia, that my cat will perish, that my house will be damaged, and that other dreadful things will befall me. The peer pressure to turn on the heat has been enormous. It’s got me thinking about heat-dependency as a sort of addiction around here. Maybe another post on that later.

But here’s a graphic depiction of how far the experiment has gone. The red and blue lines are Portland’s average high and low temps over the course of an average year. Arrow “A” shows roughly where I, and most others around here, tend to flip on the heat in the fall– sometime in October, around the first good frost. Arrow “B” shows where (barring a miraculous conversion on my housemate’s part) I will turn on the heat this winter.

As you can see, at this point we’re only a couple weeks, and a couple degrees, away from the annual temperature nadir. It would be easy, at this point, to push on through to the warming-up side of the graph. The experiment has to end for social reasons, but not for any other. I’m convinced that a whole winter without the furnace would be completely feasible and, even, enjoyable.

I’ll continue posts about things as they come to me. And I’ll be thinking about next year. And there still won’t be any heat in my bedroom, regardless.

No Furnaces, But Not Called Whackos

December 27, 2008

Many thanks to Brushfire for sending over this article from today’s NY Times, about “passively” heated houses being built in cold climates with no furnace at all. These people I think I could get along with. Of course, as usual, they are mostly not in this country.

I have a few disagreements with some of the author’s statements, mainly in regard to the feasibility of living furnace-free in a house that was not designed for it. They envision this experience as “wearing thick pullovers, turning the thermostat down and putting up with drafts.” I’ve found that with a little retro-fitting of my own self (physiologically and psychologically) I don’t need much in the way of “thick pullovers”. And as I wrote before, there are actually far fewer drafts in a house that is purposefully kept colder. And since I do, actually, kind of “treasure an experience like drinking hot chocolate in a cold kitchen”, it’s possible that “the houses may be too radical” for me (?!?). They also mention that these passive designs would fail “on an urban street with no south-facing wall”– to which I say, baloney. You’ll just not be quite as warm. You won’t freeze.

Human nature being what it is, though, the future is unlikely to be in re-acquainting ourselves with the feasibility of living in cooler houses. It is more likely to be in using new technology to keep us at the level of comfort to which we have grown accustomed.

This summarizing part of the article I agree with wholeheartedly:

“…those who want passive-house mansions may be disappointed. Compact shapes are simpler to seal, while sprawling homes are difficult to insulate and heat. Most passive houses allow about 500 square feet per person, a comfortable though not expansive living space. Mr. Hasper said people who wanted thousands of square feet per person should look for another design. ‘Anyone who feels they need that much space to live,’ he said, ‘well, that’s a different discussion.’ “

I still say cold = too big. I’m living in 1300 sq ft per person (not counting Cat as a person), but it’s more than I need– when my new housemate arrives tomorrow, that will drop down to 650. Before you tell me you can’t live without heat, tell me how many square feet you’re living in…

Heat Still Off

December 26, 2008

Just an update, in case you were wondering if I’d frozen to death. (Answer: No.) Certainly I’d envisioned that by this point my heat would be on, or else I’d be running three space-heaters full-tilt around the clock to stay alive. Neither is the case. I use one space heater, at partial-tilt, for parts of the day (sometimes two heaters for brief periods, if I have company and they might object to a cold bathroom.) I have used the electric blanket some lately, while sick, just to stay warm on the sofa– but that uses only 150 watts. It’s pretty much like sitting on a lightbulb. I’ll admit to cooking and baking somewhat more these days than usual, which does warm up the kitchen, but I find no shame in that. And I’ve gotten much better about deviously reclaiming heat from doing dishes, showering, and drying laundry.

Now the solstice has passed… Christmas has passed… still I haven’t seen a need for the central heat. We’re getting more and more sunshine every day, which encourages me. Statistically, the next four weeks are the coldest of the year here. But, statistically, they won’t be much colder than it’s been already. So, no promises, but it seems conceivable that the switch could stay off altogether this year.

You might be wondering how this is possible– to pass a winter in New England without turning on the heat. I’m kind of wondering myself. I wouldn’t have believed it two months ago. The little auxiliary bits of alternative heat mentioned above do add up and help. But beyond that, I think it comes down to three factors: Physiology, physics, and psychology.

Physiology: With just a space heater or two, your house simple isn’t going to be so-called “room temperature” (68F/20C). Your body will need to get used to being less warm. I’m finding out, it’s not that hard. Another post later on the mysteries of human cold adaptation; but I can attest that I now routinely feel comfortable in temperatures which, in October, would’ve had me shivering. In fact, I have noticed only three shivering periods: (1) Shaving in the morning, with wet face and bare chest– but this is followed by hot shower; (2) Undressing in the evening & putting on cold PJs– but this is followed by warm sleep; and (3) While sick– this was miserable, but I think unrelated. Otherwise, my body’s now pretty happy inside at a temp of about 54F/12C during the day and 38F/3C for sleeping. Getting used to temps in this range is definitely the prerequisite.

Physics: It’s astonishing how much less effort is it to keep the house at 50F/10C than it is to try to maintain 68F/20C. Temperature differentials play into everything. A cold house loses what heat it does have much less quickly than a hot house. It’s much easier to keep up with replacing it. This is something I never really had an instinct for, prior to the Cold House experiment. In the old days, if it was 15F outside, and I had my house at 68F, and turned the heat off for the night, it wouldn’t surprise me to wake in the morning up finding the indoor temp had dropped 14 degrees to 54. Which, initially, led me to some fright that my water pipes could freeze if I went to bed with the house at 50… because the same spread (50 minus 14) starts to get uncomfortably close to freezing.

But this just doesn’t happen. The closer the house gets to the outside temp, the more slowly it cools. I never see a general 14 degree drop overnight now. Maybe 5 or 6 degrees, on a really cold night. If the house is anywhere above 40F, and the outdoors isn’t below 0F, I don’t have any worry now about freezing pipes while I sleep.

And happily it works in the reverse, too– the colder the house is, the more heat gets reclaimed, faster, from warm stuff going on. I mentioned before that my pleasant surprise realizing that if my bathroom is below 48F, I actually get heat from the municipal cold water when it refills the toilet tank. That’s fun, but pretty trivial. More considerable is the amount of heat my cast-iron bathtub soaks up from a hot shower; full post on that coming later, but suffice to say, when the tub starts really cold, it absorbs a lot more of the water-heat than if it starts warm. And the colder I let my kitchen get overnight, the more heat I get back from my dishwasher-bucket. And so on. Between these two benefits, it’s really not that hard to keep the house in the 50F/10C range without the furnace.

Psychology: Stay tuned, I’m thinking about that one.

Psychology Of Water Vapor

December 12, 2008

SUNDAY, NOVEMBER 30, 2008

Now here’s another fascinating tidbit I came across in my cold-adaptation research: Did you know that the “relative” in “relative humidity” is “relative to how much water the air could hold, at the current temperature”? Hot air can hold more moisture than cold air. So if you keep the actual amount (mass) of water in the air the same, higher temperatures give lower relative humidities. And since the relative humidity determines how fast damp objects (such as our bodies) dry out, this is what we perceive. From a human perspective, the absolute amount of water vapor in the air is fairly meaningless, unless you know the temperature.

From the limited data I can find out there, humans seem to feel physically and psychologically best at relative humidities between 40% and 60%. More than that starts to feels “muggy” in hot weather and “dank” in cool weather.

At the other end of the spectrum, people around here often complain that the “air is too dry in the winter”, causing dry eyes, chapped lips, etc. But it seems that to at least some degree, this perceived “too dry”ness is primarily indoors, manmade, and a result of (guess what?) artificial heating.

Take this morning, for example. In the Smallish City right now it’s cool and cloudy outside. A small sleet-storm is edging its way towards us for later in the day. The temperature is 28F (-2C) and the relative humidity is 78%. Walking around outdoors, you certainly don’t feel the air is “too dry”. The cold air can’t hold much absolute moisture, but it’s holding about as much as it can– so your body isn’t drying out quickly. If anything, it borders on feeling “dank” out there. And when the sleet starts, it will surely feel downright wet.

Here in my kitchen, however, I have a space heater running to keep the temperature at a toasty 51F (10.5C). The actual amount of water in the air is about the same as outside. But at this indoor temperature, the air could hold a lot more water vapor. The relative humidity drops to 32%– feeling just a bit on the dry side, but still fine for me.

I look out at Accordion Neighbor’s house, though, and notice that he’s got his woodstoves cranking. He probably has it up to 68F (20C) in his house, like “normal” people. At that scorching temperature, the relative humidity in his place right now is a parching 17%. The water is being sucked out of his family’s bodies into the hot air. He probably has chapped lips, his kids might have bloody noses and dry throats (indeed, I haven’t heard them scream in several days), and they are all probably going through hand-moisturizer at a rapid clip.

A.N. is probably trying to counter this problem with an old trick: keeping a kettles of steaming water on top of the woodstoves to get some extra humidity into the air. (A similar old trick is used around here by those with radiator heat: narrow buckets of water that hang from the radiator, getting warm & evaporating moisture into the air.) This trick isn’t necessarily a bad idea, for human comfort– but from a standpoint of energy-efficiency it’s very much a losing battle. In an old house, it won’t be long before that water vapor makes its way back outdoors. And, as we learned in a previous thought-experiment, evaporating water costs you temperature, and energy. Every gallon of water you purposefully evaporate costs you a couple pounds of nice firewood, or cup of fuel oil.

So, call me a crackpot, but: one way to keep yourself feeling dried out in winter is to keep your house cooler.
POSTED BY TURBOGLACIER AT 10:17 AM
7 COMMENTS:

Johanna said…
Me, I am not swayed by all the arguments for sitting around feeling cold, and I am still trying to wrap my head around this concept of not turning on the furnace to save energy while managing to convince oneself that using an inefficient electric clothes dryer makes economic, environmental or common sense.

I am waiting for the day you actually turn on the heat and focus your thoughts on preventing heat loss, because that’s information I could apply.

11/30/08 12:56 PM
Turboglacier said…
Oh, I’m focused on preventing heat loss, too, inasmuch as that is reasonably feasible. I’ve gone around and caulked all the window cracks. I am putting additional plastic insulation on some of them. I injected foam in many baseboard cracks. I put foam behind drafty electrical outlets. I’m sealing up holes in the basement through which cold air came in (such as the big hole formerly used by the dryer vent.) But, short of a multi-thousand dollar jobs such as re-insulating the walls or replacing all the windows, this is all I can do for the moment.

As for the electric dryer: I have to disagree with the common sense. The dryer is basically just a big electric heater. It’s electricity (in fact, ANY electricity used in the house) is ultimately turned, with 100% efficiency, into heat (with the exception of a miniscule amount that may escape as light.) So, as long as you manage to keep that heat in the house, you’re maintaining perfect efficiency.

(Making the electricity in the first place, of course, is not a 100% efficient process– but neither by a long shot is running the furnace. Depending on the source of the electricity, it’s arguably “greener” than burning oil here at home.)

11/30/08 1:33 PM
C Neal said…
Remember that warm, dry air is actually perceived by humans to be less warm than warm, moist air. A room with a thermostat set at 60 and with 80% relative humidity feels just as warm as a room where the thermostat is set at 65, with only 10% RH. See this chart from NOAA:

http://www.infoplease.com/ipa/A0001434.html

As I understand it, dry air feels colder because it increases the rate of evaporative cooling on your skin (conversely, in the summer, hot, humid air decreases the rate of evaporative cooling and makes it feel hotter than it actually is). So the kettle on the stove or the bucket on the radiator may decrease performance in terms of actual temperature, but in terms of perceived temps, it may well be an improvement.

I’ll leave it to you to figure out the details of the trade-off.

11/30/08 2:22 PM
Turboglacier said…
C.Neal: That is most interesting. But I think it still doesn’t come out in Accordion Neighbor’s favor. With this morning’s conditions, if AN set his thermostat at 70F, his humidity would be 16%, and chart says he would “feel like” it was about 64.5F (interpolating between the data points.)

Meanwhile, even if I (uncharacteristically) let my house go up to 60F, I would have a humidity of 23%, and would “feel like” 56.5F. So, AN’s house feels 5.5˚ cooler than it is, but mine feels only 3.5˚ cooler than it is. To make up the two degrees in “feel”, he can make the house warmer, or more humid, but either way he’s using even more fuel. Chasing the tail, I call it.

[Also: I was annoyed with that chart, because it only goes down to 60˚F, whereas my house is considerably cooler. But then I noticed a trend which leads me to question its validity altogether: as the temperatures go down, the chart says you need more humidity to “feel” like you’re at that actual temperature. By 60F, you need 80-90% humidity just to “feel” like it’s 60F. If you extrapolate this pattern just a few degrees, at about 57F you’ll need 100% humidity to “feel like” 57F. At temperatures below that, “feeling like” the actual temperature would take humidity >100%, which isn’t possible. So… I surmise that this chart is good only for a very narrow range of temps– probably not even down to 60F, and certainly not below that.]

11/30/08 3:34 PM
girltuesday said…
ok, i’ll bite: crackpot.

11/30/08 10:51 PM
Victor said…
Oh, I grew up in Very Smallish town with cold (-20°C) winters and, the chart cannot be – as you suggest – valid for colder temperatures. The amount of water in the air also affects the convection and conduction of heat. In “cold” (< 4°C as a qualified guess) temperatures an increasing relative humidity will be percieved as the air getting colder. This is why +3 and rain feels in october feels like -8°C and -20°C with a clear sky in january feels like -8°C.

This are just opinions. And this was a very nice blog!

12/10/08 9:57 AM
Anonymous said…
More than you ever wanted to know about apparent temperature (with equations!): http://www.srh.noaa.gov/ffc/html/studies/ta_htindx.PDF

12/10/08 6:50 PM