Archive for the ‘Summer cooling’ Category

Cold Rocks

July 7, 2010

Frankly, I do not know how people manage to live anywhere south of the 43rd parallel.  It has been plenty hot enough here– but I know I don’t have much to complain about, when it’s been over 100ºF (38C) in Boston and New York and Philly and Baltimore.  Those places, I’d perish.  Here, it’s just damn hard to sleep.

So last night (would’ve done it sooner, if I’d thought of it) I pulled out the bedwarmer stones that have been sitting idly since March and threw them in the freezer for half an hour before bed.  Aaaahhh!  Absolutely delightful.  J. put one under her feet.  I lay on my back and put mine right on my chest.  Really, really good.  Try it.  Use a pizza stone, or a flat rock from the back yard, or whatever you can find.

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Backstory

March 9, 2010

A little while ago I had the pleasure of speaking with “The History Guys”, producers of the National Public Radio show “Backstory”, for a story the were doing on the history of home heating and air-conditioning.  The piece is out on their website now; you can listen here.  I learned a lot.  I also found the “Further Reading” fascinating.

More On Warm Houses

July 30, 2009

The New York Times took up the idea of white roofs with an article today. It goes into some interesting history on why places like Florida would have buildings with black roofs. The author also notes that “the extra heating costs [of white roofs] may outweigh the air-conditioning savings in cities like Detroit or Minneapolis [or Maine]”. Strangely (to my mind), there isn’t a mention of what seems like the logical next step: finding a simple way to turn black roofs white for the summer, then back to black for the winter.

My experiment in that very idea is working well. I’ve only actually covered half of my roof (out of pure laziness, really– I just haven’t unrolled the other half) but so far it’s been rather comfortable in the house, with none of those stiflingly hot no-sleep nights yet. I suppose they may be coming in August. I’ll get the other half covered soon.

Warm House Journal

July 11, 2009

I do live in Maine, but I also live in the middle of the state’s largest urban heat island (such as it is, in Maine.) So believe it or not, there is a brief stretch here– roughly from July 4th to Labor Day– when the weather has the potential to get uncomfortably warm. Out of those two months there are maybe eight hot nights when I lie awake in the second floor bedroom, sweltering, thinking about sleeping amidst the creepy-crawlies in the basement/dungeon. Now and then I get a fleeting urge to buy an air conditioner, but it never rises to the level of action.

This year, as spring wore on, I started to think whether there were any passive strategies I might use to get the house a little cooler (other than fans, which I already employ extensively.) My first fantasies involved heat-sensitive, color-changing exterior house paint– say, a paint that is black in the winter, but white in the summer. This is a nice idea, but so far as I can tell, the technology isn’t quite ripe yet. ( This company) makes some cool paint that does almost what’s called for– but at $429 a quart the paint job might cost more than the house is worth.)

Temporarily changing the color of the roof, though, struck me as relatively simple.

We have a flat roof with a black asphalty-rubber surface. I don’t know how much solar heat it absorbs in the winter (it’s usually covered with snow), but in the summer it gets “wicked” hot– empirically, hot enough to scorch bare feet, on a sunny hot day. I resolved to try covering the roof in some sort of white fabric. A la Christo.

I went through various material options, almost settling on scrap Dacron sailcloth. But I decided to try plain old white cotton first, buying 400 sq. ft from eBay for $36. It’s cheap, and if it was a failure, at least it’s biodegradable. Plus, it can absorb a little water, which I thought would provide opportunity to try a secondary strategy of evaporative cooling (by spritzing it on extra-hot days.) It did occur to me that cotton would be susceptible to growing mold when damp, but I thought it would get enough sun between rainstorms that it would more or less get sanitized.

That was before I knew it was going to rain like the bejesus all of June and into the first week of July. I carried the heap of folded fabric up on the roof the first week of June, but it started sprinkling on me, so I decided to wait till the rain stopped to unfold it. I had to wait over a month. By that time, it was getting kind of slimy. Ew. But I spread half of it out anyway, to test.

Here’s how it looks:And good news: it works. When we finally got a sunny day, I took temperature measurements at the surface. The black part was 99.0F (37C). The white part was 82.6F (28C). And this, I should mention, was at 5pm, as the sun was getting pretty low– at noon, probably a bigger differential. Anyway, I’m convinced that covering the whole roof will be enough to lower my upstairs house temperature at least five degrees on the hottest of days, which is all that’s really needed. Can’t wait!

(P.S. While I was waiting for a break in the weather to roll out my white roof, the U.S. Energy Secretary came out in favor of white roofs too. His suggestion is that eliminating heat absorption from black roofs could stop global warming. Up north here, though, a black roof is a benefit in the cold months.)

P.S. On A/C

January 5, 2009

I was just perusing our federal government’s [rather limited] tax credits for homeowner energy-conservation measures. I was somewhat unhappy to see that we give credits for purchasing “energy-efficient” A/C systems. And even more unhappy to see that this credit ($300) is twice the credit for energy-efficient heat furnaces ($150). And did I get any tax credits for the three $30, 100W window fans that I use instead of A/C? Nooo.

Wouldn’t it make more sense to pay people $500 to have no A/C? Or give such people free fans? Or at least a letter of merit? One has to suspect the long arm of the A/C industry lobby when you see these sorts of things.

Not Cold Enough For Most Americans

January 3, 2009

In the process of writing the last post, I discovered incidentally another way in which I am apparently a whacknut: I don’t have an air-conditioner. The trend has been grossly in the other direction. According to the Department of Energy, as of 2001, only 22% of Americans live this way. The majority of U.S. households have central A/C. Even among locals here, it’s abnormal to live with ambient summer temperatures: by 2001 only 42% of New Englanders were “suffering” without A/C (around 1980, it was 60%– so “normal” has swung the other way over the course of my lifetime.)

The DOE data table only goes through 2001, but the “progress” looked pretty linear, so I made a graph to see where the trend might be heading. It’s kind of frightening. If things continue on this course, the A/C-free American house will be virtually extinct within 10 years. Wow.


I can only interpret this in two ways: Either (a) we are getting as intolerant of summer heat as we are of winter cold, and adding extra A/C just to keep up with our own growing demands for “comfort”, or (b) the climate is actually getting warmer, and we need more A/C just to keep houses the same temperature they used to be without A/C. Possibly both. And since (a) might cause (b), and (b) might exacerbate (a), it looks like a bad combination.