Sash windows can be a very effective source of ventilation
July 17, 2022 4:00 PM Subscribe
The science behind sash windows (YouTube) TLDR: Two openings at different heights will maximise airflow/cooling. The Q&A at the end covers building efficiency and ventilation for heat/cool/viral transmission.
AKA "double hung" in the US. Any part of a window that moves in the US, no matter what the operation is, is called a "sash".
posted by LionIndex at 4:17 PM on July 17, 2022 [8 favorites]
posted by LionIndex at 4:17 PM on July 17, 2022 [8 favorites]
My first home had double hung windows. Within the frame are sash weights. They hang from, in my case, ropes. They balance the weight of the actual window parts so that the window stays in place. OTOH in an ancient home, sometimes the rope rots away. So that the actual weights fall to the bottom. And so do the windows. On your fingers. Ask me how I know.
posted by Splunge at 4:24 PM on July 17, 2022 [22 favorites]
posted by Splunge at 4:24 PM on July 17, 2022 [22 favorites]
Once you've got those windows open, watch this: Best fan placement to move air through the house [YouTube]
posted by theory at 4:33 PM on July 17, 2022 [6 favorites]
posted by theory at 4:33 PM on July 17, 2022 [6 favorites]
Haven’t finished the vid but I remember visiting the Tenement Museum in NYC and there was a double hung window on the interior wall between the living room and kitchen, called a “tuberculosis window” .
posted by brachiopod at 5:23 PM on July 17, 2022 [6 favorites]
posted by brachiopod at 5:23 PM on July 17, 2022 [6 favorites]
Watching this ATM in the middle of the Q+A section, a viewer asks about how this may effect the spread of covid, and in her reply she mentions the efficacy of masks.
I picture in my mind's eye some pinhead, who doesn't understand the difference between science and opinion, groaning and saying 'well I didn't know this was going to be political'.
posted by adept256 at 5:40 PM on July 17, 2022 [3 favorites]
I picture in my mind's eye some pinhead, who doesn't understand the difference between science and opinion, groaning and saying 'well I didn't know this was going to be political'.
posted by adept256 at 5:40 PM on July 17, 2022 [3 favorites]
Not that such a person would even get this far into a science lecture.
A very timely tip for those about to go through a heat wave. I'm going to throw in my standard tip from an Aussie to those who have never experienced such heat before: if you have a chest freezer, you can keep your pillows in there.
England is particularly screwed because their housing is designed to keep the heat trapped inside. 40 degrees is going to be brutal.
posted by adept256 at 5:47 PM on July 17, 2022 [2 favorites]
A very timely tip for those about to go through a heat wave. I'm going to throw in my standard tip from an Aussie to those who have never experienced such heat before: if you have a chest freezer, you can keep your pillows in there.
England is particularly screwed because their housing is designed to keep the heat trapped inside. 40 degrees is going to be brutal.
posted by adept256 at 5:47 PM on July 17, 2022 [2 favorites]
We are replacing a bunch of old, worn out vinyl windows in our house this year, and the window guy was trying to convince us to go with single hung windows because they were “more efficient”. I can’t figure that one out, but sure enough you get twice the energy retrofit rebate back for single hung windows than double hung. We went for double hung anyways, because being able to open the top and bottom of the window is better.
posted by fimbulvetr at 5:50 PM on July 17, 2022 [1 favorite]
posted by fimbulvetr at 5:50 PM on July 17, 2022 [1 favorite]
Every single house I've ever lived in with double hung windows has had the top sashes painted into place. Including my current house, rip.
posted by Ferreous at 5:59 PM on July 17, 2022 [17 favorites]
posted by Ferreous at 5:59 PM on July 17, 2022 [17 favorites]
When looked at solely from the lens of energy leaking from a conditioned (a/c or heat) home, double-hung windows are the least efficient style of window. The advantage of a double-hung window comes when you turn off the HVAC system.
posted by Big Al 8000 at 6:19 PM on July 17, 2022 [6 favorites]
posted by Big Al 8000 at 6:19 PM on July 17, 2022 [6 favorites]
Century houses are remarkably efficient at managing interior temperatures without HVAC as long as you know how to use them. In the summer, you close the windows and heavy drapes on the sun side of the house and open cool-air entry windows on the shaded side, and warm-air exit windows in the attic. At night, open cross-flow windows so the mass of the house cools down. Ideally there will be trees blocking the majority of the sun-side of the house; lacking that, growing ivy on your bricks is good.
This still works with modern houses but they are often less well designed for cross-flow and lower floor to attic hot air ventilation.
posted by seanmpuckett at 6:29 PM on July 17, 2022 [22 favorites]
This still works with modern houses but they are often less well designed for cross-flow and lower floor to attic hot air ventilation.
posted by seanmpuckett at 6:29 PM on July 17, 2022 [22 favorites]
I have not ever really considered making two openings with our windows because the insect screen only covers the bottom sash. If I open the top, it'll let all the bugs in.
posted by backseatpilot at 6:41 PM on July 17, 2022 [12 favorites]
posted by backseatpilot at 6:41 PM on July 17, 2022 [12 favorites]
They look dorky, but the adjustable fits-most window screens are great for using top sashes for ventilation.
posted by clew at 6:47 PM on July 17, 2022 [1 favorite]
posted by clew at 6:47 PM on July 17, 2022 [1 favorite]
England is particularly screwed because their housing is designed to keep the heat trapped inside. 40 degrees is going to be brutal.
Tell me about it. I live in a place that gets to -40 C in the winter. To say our homes were not built for the +40 C temps we experienced in the heat dome last summer would be an understatement. I genuinely fear extreme heat much more than I fear extreme cold.
posted by hurdy gurdy girl at 7:02 PM on July 17, 2022 [2 favorites]
Tell me about it. I live in a place that gets to -40 C in the winter. To say our homes were not built for the +40 C temps we experienced in the heat dome last summer would be an understatement. I genuinely fear extreme heat much more than I fear extreme cold.
posted by hurdy gurdy girl at 7:02 PM on July 17, 2022 [2 favorites]
And so do the windows. On your fingers.
Or other things. Tristram Shandy has pretty much radicalized me on the issue of sash windows.
posted by phooky at 7:03 PM on July 17, 2022 [4 favorites]
Or other things. Tristram Shandy has pretty much radicalized me on the issue of sash windows.
posted by phooky at 7:03 PM on July 17, 2022 [4 favorites]
Our home, built in 1936, has double-hung windows throughout the home. When we looked at it the first time, my husband’s eyes lit up because the double hungs all worked. We opened a couple on the main floor, opened the front door, and after he opened a window on the second floor, the resulting draft was so strong the front door slammed shut!
We *love* being able to evacuate the warm air quickly.
He also built us some storm windows for winter time (this type of window can be leaky), and an energy audit revealed they were as “efficient” as modern windows. Quotes used in that last sentence because glass is a very, very bad insulator. So modern windows with dual pane and some kind of gas in between? It’s still glass. Triple pane are marginally better, but at a much higher cost. Removable storm windows ftw.
posted by dbmcd at 7:10 PM on July 17, 2022 [9 favorites]
We *love* being able to evacuate the warm air quickly.
He also built us some storm windows for winter time (this type of window can be leaky), and an energy audit revealed they were as “efficient” as modern windows. Quotes used in that last sentence because glass is a very, very bad insulator. So modern windows with dual pane and some kind of gas in between? It’s still glass. Triple pane are marginally better, but at a much higher cost. Removable storm windows ftw.
posted by dbmcd at 7:10 PM on July 17, 2022 [9 favorites]
Last time we were in Europa, those German Tilt & Turn windows were cool.
posted by ovvl at 7:19 PM on July 17, 2022 [4 favorites]
posted by ovvl at 7:19 PM on July 17, 2022 [4 favorites]
There's a cool little toy you can buy called a solar radiometer. They're like a light bulb with a little solar powered propeller inside. It's pretty low tech - one side of the propellor is shiny and the other matte and that's all there is to it. If you have a couple of these you can get a good idea of how much heat is being blocked by your window panes, just put one outside and one inside. UV treated glass will slow these to a crawl.
I love radiometers. They're the most easily understandable demonstration of solar power you could wish for. They're not expensive either, search your online capitalism hub.
posted by adept256 at 7:27 PM on July 17, 2022 [9 favorites]
I love radiometers. They're the most easily understandable demonstration of solar power you could wish for. They're not expensive either, search your online capitalism hub.
posted by adept256 at 7:27 PM on July 17, 2022 [9 favorites]
And so do the windows. On your fingers.
An easy fix is to install sash springs, either on the jambs or on the sashes themselves.
posted by hydrophonic at 10:33 PM on July 17, 2022 [1 favorite]
An easy fix is to install sash springs, either on the jambs or on the sashes themselves.
posted by hydrophonic at 10:33 PM on July 17, 2022 [1 favorite]
I'm not sure if I've ever seen a double hung window, much less operated one, and now I'm bothered that my home doesn't have them.
I wonder how many of these traditional technologies to regulate temperature has been lost to time under the assumption that electricity and air conditioning would solve all of our problems forever.
posted by meowzilla at 11:33 PM on July 17, 2022 [4 favorites]
I wonder how many of these traditional technologies to regulate temperature has been lost to time under the assumption that electricity and air conditioning would solve all of our problems forever.
posted by meowzilla at 11:33 PM on July 17, 2022 [4 favorites]
Also what I'm hearing from this video is that window fans are useless unless you have open windows on the other side of your house. A window fan set to push air in or out does little when the room (or entire house) is closed.
posted by meowzilla at 11:36 PM on July 17, 2022 [1 favorite]
posted by meowzilla at 11:36 PM on July 17, 2022 [1 favorite]
Century houses are remarkably efficient at managing interior temperatures without HVAC as long as you know how to use them. In the summer, you close the windows and heavy drapes on the sun side of the house and open cool-air entry windows on the shaded side, and warm-air exit windows in the attic. At night, open cross-flow windows so the mass of the house cools down.
I suppose using thermal mass + air circulation worked reasonably well in the past but when the "cool-air entry" window today is bringing in 40°C air into your house, that's not helping.
And thermal mass becomes your enemy when you have a sustained heat wave over several days that doesn't really cool down at night, so the heat builds up more and more.
I'm fortunate to live in a somewhat modern house and it's eye opening that the construction concepts today are the complete opposite of how we used to build houses in the past. Today's houses work towards minimizing thermal mass and making the house airtight.
For example last night it was 0°C where I am and my sleeping / living area (basically bedroom + study + ensuite bathroom + walk-in-robe) which I use as a work from home space - is maintained at 23°C all day and night using a reverse cycle air conditioner in heating mode which consumes just 300 watts at night according to my power meter. It's able to maintain a 23°C temperature differential for just 300 watts of power - 5.5 cents per hour, which is astounding, and it works the same in reverse as well when the outside is 45°C and you want the inside at 25°C in summer.
In fact there was one 43°C day where we got home at 3pm then just had a nap under the blankets because it was so cool indoors... we didn't need to use any cooling or fans at all that night either.
The main concern people have now is that with airtight houses, ventilation suffers, especially when we're talking about Covid. Humidity issues are eliminated using vapor permeable waterproof membranes for your walls and roof, and a lot of air quality issues are mitigated by using induction / heat pump type cooking and heating instead of gas, as well as using powerful kitchen hoods / bathroom extraction fans. But the air changes per hour is much lower. There's been some work done in mechanical heat recovery ventilation where it allows you to exchange indoor air with outside air without affecting the indoor temperature, but those systems are still really exotic nowadays. The only common application for heat recovery right now is for commercial kitchens who want to recover the heat from their industrial dishwasher, where the hot waste water runs along a pipe-within-a-pipe design and exchanges heat with the incoming mains cold water. Mechanical ventilation in ultra-modern homes will exchange stale indoor air with fresh outdoor air through a heat-exchanger that will neutralize the temperature differences between them.
posted by xdvesper at 12:01 AM on July 18, 2022 [9 favorites]
I suppose using thermal mass + air circulation worked reasonably well in the past but when the "cool-air entry" window today is bringing in 40°C air into your house, that's not helping.
And thermal mass becomes your enemy when you have a sustained heat wave over several days that doesn't really cool down at night, so the heat builds up more and more.
I'm fortunate to live in a somewhat modern house and it's eye opening that the construction concepts today are the complete opposite of how we used to build houses in the past. Today's houses work towards minimizing thermal mass and making the house airtight.
For example last night it was 0°C where I am and my sleeping / living area (basically bedroom + study + ensuite bathroom + walk-in-robe) which I use as a work from home space - is maintained at 23°C all day and night using a reverse cycle air conditioner in heating mode which consumes just 300 watts at night according to my power meter. It's able to maintain a 23°C temperature differential for just 300 watts of power - 5.5 cents per hour, which is astounding, and it works the same in reverse as well when the outside is 45°C and you want the inside at 25°C in summer.
In fact there was one 43°C day where we got home at 3pm then just had a nap under the blankets because it was so cool indoors... we didn't need to use any cooling or fans at all that night either.
The main concern people have now is that with airtight houses, ventilation suffers, especially when we're talking about Covid. Humidity issues are eliminated using vapor permeable waterproof membranes for your walls and roof, and a lot of air quality issues are mitigated by using induction / heat pump type cooking and heating instead of gas, as well as using powerful kitchen hoods / bathroom extraction fans. But the air changes per hour is much lower. There's been some work done in mechanical heat recovery ventilation where it allows you to exchange indoor air with outside air without affecting the indoor temperature, but those systems are still really exotic nowadays. The only common application for heat recovery right now is for commercial kitchens who want to recover the heat from their industrial dishwasher, where the hot waste water runs along a pipe-within-a-pipe design and exchanges heat with the incoming mains cold water. Mechanical ventilation in ultra-modern homes will exchange stale indoor air with fresh outdoor air through a heat-exchanger that will neutralize the temperature differences between them.
posted by xdvesper at 12:01 AM on July 18, 2022 [9 favorites]
Our house in the Irish midlands was built in 1941 with double-hung sash windows. The frames were fitted with war glass which was translucent but not crisply transparent - we could see the hill on the other side of the valley but not the sheep on it. Also single glazed; so in 1996 at purchase we keep [most of] the frames and installed sealed double glazing units. But that buggered up the counter-weighting. Undaunted, our contractor got a roll of lead roof-flashing and an agricultural scales and wrapped the original sash-weights with enough lead to equal the extra leaves of glass - there's a Whitman joke in there somewhere. We're stripped down and lolling in front of shady-side windows in anticipation of the hottest day "possibly up to 32 degrees in places on Monday" since 2018. More significantly on the utilitarian front, the sheep were shorn last night.
posted by BobTheScientist at 12:43 AM on July 18, 2022 [7 favorites]
posted by BobTheScientist at 12:43 AM on July 18, 2022 [7 favorites]
England is particularly screwed because their housing is designed to keep the heat trapped inside. 40 degrees is going to be brutal.
My last place in London was a loft apartment at the top of a Victorian building, immediately under a black slate roof. In the summers, it was like an oven, typically at least 10° over the outdoor temperature. It was also the only place I ever owned an air conditioner, despite having lived in Australia. The last summer I was there, the brave little air conditioner struggled 24 hours a day to keep it just about habitable. (Did I also mention that the windows on one side were not openable due to the vent from the kebab shop downstairs pointing at them?)
I do not envy whoever is living there now.
posted by acb at 1:35 AM on July 18, 2022 [3 favorites]
My last place in London was a loft apartment at the top of a Victorian building, immediately under a black slate roof. In the summers, it was like an oven, typically at least 10° over the outdoor temperature. It was also the only place I ever owned an air conditioner, despite having lived in Australia. The last summer I was there, the brave little air conditioner struggled 24 hours a day to keep it just about habitable. (Did I also mention that the windows on one side were not openable due to the vent from the kebab shop downstairs pointing at them?)
I do not envy whoever is living there now.
posted by acb at 1:35 AM on July 18, 2022 [3 favorites]
Building desgin and specifically use of mass and or ventilation and or building design/shading are location/climate dependent. All the mass and ventilation in the world isn't going to help you if the air temperature never drops below desired room temperature over the course of the day. Shading with trees is great but one of the reasons they help is they dump massive amounts of water into the air which does squat if the humidex is high (obviously they still reduce solar gain.)
There's been some work done in mechanical heat recovery ventilation where it allows you to exchange indoor air with outside air without affecting the indoor temperature, but those systems are still really exotic nowadays.
HRVs are essentially standard equipment in new houses in my part of Canada.
posted by Mitheral at 1:59 AM on July 18, 2022 [2 favorites]
There's been some work done in mechanical heat recovery ventilation where it allows you to exchange indoor air with outside air without affecting the indoor temperature, but those systems are still really exotic nowadays.
HRVs are essentially standard equipment in new houses in my part of Canada.
posted by Mitheral at 1:59 AM on July 18, 2022 [2 favorites]
the actual weights fall to the bottom. And so do the windows. On your fingers.
Mr. Jolly Lives Next Door
posted by Lanark at 3:12 AM on July 18, 2022
Mr. Jolly Lives Next Door
posted by Lanark at 3:12 AM on July 18, 2022
Removable storm windows ftw.
Many victorian houses in the UK have solid window shutters like this, which are great for insulation, providing they haven't been painted shut.
posted by Lanark at 4:06 AM on July 18, 2022
Many victorian houses in the UK have solid window shutters like this, which are great for insulation, providing they haven't been painted shut.
posted by Lanark at 4:06 AM on July 18, 2022
(obviously they still reduce solar gain.)
Solar gain reduction is too important to be left in a parenthetical. The EPA says that "shaded surfaces...may be 20–45°F (11–25°C) cooler than the peak temperatures of unshaded materials." That's not entirely down to evapotranspiration or no one would bother with patio umbrellas or market tents. And in a city, where all the masonry and impermeable surface can absorb sunlight during the day and then radiate it back out at night (reducing overall nighttime cooling), that reduction in solar gain could have real impact, especially when temps are very high. When it's as hot as 40° (104°) even a few degrees of extra cooling could be life-saving.
Planting trees is certainly not a short-term strategy, however. One thing we have seen very clearly over the past few years is that, globally, local temperatures are becoming very unstable, so that the assumptions which our current building stock and city designs are based on (England has moderate year-round temperatures, for example) cannot be relied upon. I'm not sure we can afford to dismiss any (passive or active) temperature mitigation strategy simply because it's not immediately relevant.
posted by radiogreentea at 6:24 AM on July 18, 2022 [2 favorites]
Solar gain reduction is too important to be left in a parenthetical. The EPA says that "shaded surfaces...may be 20–45°F (11–25°C) cooler than the peak temperatures of unshaded materials." That's not entirely down to evapotranspiration or no one would bother with patio umbrellas or market tents. And in a city, where all the masonry and impermeable surface can absorb sunlight during the day and then radiate it back out at night (reducing overall nighttime cooling), that reduction in solar gain could have real impact, especially when temps are very high. When it's as hot as 40° (104°) even a few degrees of extra cooling could be life-saving.
Planting trees is certainly not a short-term strategy, however. One thing we have seen very clearly over the past few years is that, globally, local temperatures are becoming very unstable, so that the assumptions which our current building stock and city designs are based on (England has moderate year-round temperatures, for example) cannot be relied upon. I'm not sure we can afford to dismiss any (passive or active) temperature mitigation strategy simply because it's not immediately relevant.
posted by radiogreentea at 6:24 AM on July 18, 2022 [2 favorites]
those German Tilt & Turn windows were cool
I love those and have run into them all across Europe. It's amazing to have such a huge wide-open window, or turn the handle and just have a little bit. I don't know why bugs aren't such a problem, but they'd certainly never work where I am in the US; I had a small opening in a window screen for the past couple nights and my whole family already has at least one mosquito bite each!
Many victorian houses in the UK have solid window shutters like this
I've never seen those, but speaking of Germany, the rolladen shutters that everyone seems to have Maybe those are only in certain parts of the country or only in small enough areas? I don't remember seeing them in Hannover when I was there a few years ago, but seem to be common outside big cities. However, when you're walking around a small village and every window is shuttered with those, it makes you feel a bit like you missed the memo about the coming apocalypse...
posted by msbrauer at 6:40 AM on July 18, 2022 [1 favorite]
I love those and have run into them all across Europe. It's amazing to have such a huge wide-open window, or turn the handle and just have a little bit. I don't know why bugs aren't such a problem, but they'd certainly never work where I am in the US; I had a small opening in a window screen for the past couple nights and my whole family already has at least one mosquito bite each!
Many victorian houses in the UK have solid window shutters like this
I've never seen those, but speaking of Germany, the rolladen shutters that everyone seems to have Maybe those are only in certain parts of the country or only in small enough areas? I don't remember seeing them in Hannover when I was there a few years ago, but seem to be common outside big cities. However, when you're walking around a small village and every window is shuttered with those, it makes you feel a bit like you missed the memo about the coming apocalypse...
posted by msbrauer at 6:40 AM on July 18, 2022 [1 favorite]
Today's houses work towards minimizing thermal mass and making the house airtight...It's able to maintain a 23°C temperature differential for just 300 watts of power
The problem with many modern buildings is in a future where global warming and energy scarcity start to kick in, what happens if we get a 45C heat wave and the power goes out at the same time? Are those massive all glass pencil tower blocks going to be habitable without power?
posted by Lanark at 7:44 AM on July 18, 2022 [2 favorites]
The problem with many modern buildings is in a future where global warming and energy scarcity start to kick in, what happens if we get a 45C heat wave and the power goes out at the same time? Are those massive all glass pencil tower blocks going to be habitable without power?
posted by Lanark at 7:44 AM on July 18, 2022 [2 favorites]
Many victorian houses in the UK have solid window shutters like this
Those are called plantation shutters in the US. Exterior shutters are far better, but they work ok and are easier to maintain.
posted by The_Vegetables at 7:53 AM on July 18, 2022
Those are called plantation shutters in the US. Exterior shutters are far better, but they work ok and are easier to maintain.
posted by The_Vegetables at 7:53 AM on July 18, 2022
The problem with many modern buildings is in a future where global warming and energy scarcity start to kick in
No the problem with most modern buildings is building zoning codes that completely prevent passive strategies to go beyond the individual building. Most cities in the US have sunlight mandates, ie a building can't shade a high percentage. Most cities mandate FAR ratios (how much of a lot a building can take up, generally including porches), and most cities mandate how wide streets should be (wide). Even in places like Texas, Arizona, and California, which have excessively hot climates.
Guess what a city designed for a hot climate would look like: lots of shade, most of a lot taken up, and narrow streets. Sorry, not allowed.
posted by The_Vegetables at 8:03 AM on July 18, 2022 [2 favorites]
No the problem with most modern buildings is building zoning codes that completely prevent passive strategies to go beyond the individual building. Most cities in the US have sunlight mandates, ie a building can't shade a high percentage. Most cities mandate FAR ratios (how much of a lot a building can take up, generally including porches), and most cities mandate how wide streets should be (wide). Even in places like Texas, Arizona, and California, which have excessively hot climates.
Guess what a city designed for a hot climate would look like: lots of shade, most of a lot taken up, and narrow streets. Sorry, not allowed.
posted by The_Vegetables at 8:03 AM on July 18, 2022 [2 favorites]
The problem with many modern buildings is in a future where global warming and energy scarcity start to kick in, what happens if we get a 45C heat wave and the power goes out at the same time?
There are modern high-rise buildings stabilised by an electrically motorised pendulum in the foundations. Presumably a total power outage would be a much more severe problem for them, and yet they still stand.
posted by acb at 8:11 AM on July 18, 2022
There are modern high-rise buildings stabilised by an electrically motorised pendulum in the foundations. Presumably a total power outage would be a much more severe problem for them, and yet they still stand.
posted by acb at 8:11 AM on July 18, 2022
Guess what a city designed for a hot climate would look like: lots of shade, most of a lot taken up, and narrow streets. Sorry, not allowed.
Actually since winter and summer sun trace mutually exclusive paths it's trivial to design houses to exclude summer sun and only receive winter sun.
My estate kind of looks like this, long narrow houses oriented North to South, with just 1 meter gaps between the
| house |-- | 2 meter high steel fence | -- | house |
on the East / West aspects.
Summer sun shines mostly from the East / West so the houses being so close to each other gives each other shading in summer, also you'd want to minimize any windows facing East / West - not that there's any view to be had anyway since you're just looking at a steel fence 1 meter away from the window.
Winter sun only comes through the North / South depending on whether you're in the northern / southern latitudes - which either faces your backyard or street - so you get unrestricted heating on sunny winter days by having full length windows / sliding glass doors. Just need to pop a 500mm eave over it and it will stop any summer sun ingress.
That's what I'm a bit confused about when there was a comment above about houses "designed to trap heat" - designed this way houses only trap heat in winter when you want it, and doesn't trap heat in summer when you don't.
posted by xdvesper at 8:14 AM on July 18, 2022 [2 favorites]
Actually since winter and summer sun trace mutually exclusive paths it's trivial to design houses to exclude summer sun and only receive winter sun.
My estate kind of looks like this, long narrow houses oriented North to South, with just 1 meter gaps between the
| house |-- | 2 meter high steel fence | -- | house |
on the East / West aspects.
Summer sun shines mostly from the East / West so the houses being so close to each other gives each other shading in summer, also you'd want to minimize any windows facing East / West - not that there's any view to be had anyway since you're just looking at a steel fence 1 meter away from the window.
Winter sun only comes through the North / South depending on whether you're in the northern / southern latitudes - which either faces your backyard or street - so you get unrestricted heating on sunny winter days by having full length windows / sliding glass doors. Just need to pop a 500mm eave over it and it will stop any summer sun ingress.
That's what I'm a bit confused about when there was a comment above about houses "designed to trap heat" - designed this way houses only trap heat in winter when you want it, and doesn't trap heat in summer when you don't.
posted by xdvesper at 8:14 AM on July 18, 2022 [2 favorites]
Actually since winter and summer sun trace mutually exclusive paths it's trivial to design houses to exclude summer sun and only receive winter sun.
Except that the actual research shows that specifically designing a house for winter sun doesn't really work in most climates, because winter in generally cloudier, when you need the sun in winter is on the days its cloudier and colder, and it often gets blocked by snow or rain. And cloudiness proceeds poor weather, preventing heat build up.
But for the tiny number of climate days and locations that are not snowy, cloudy, or rainy in the winter, it's fine.
posted by The_Vegetables at 8:21 AM on July 18, 2022
Except that the actual research shows that specifically designing a house for winter sun doesn't really work in most climates, because winter in generally cloudier, when you need the sun in winter is on the days its cloudier and colder, and it often gets blocked by snow or rain. And cloudiness proceeds poor weather, preventing heat build up.
But for the tiny number of climate days and locations that are not snowy, cloudy, or rainy in the winter, it's fine.
posted by The_Vegetables at 8:21 AM on July 18, 2022
Where I live clear winter days are usually the coldest as clear days means clear nights and -20 to -30°C temperatures. Our little post-war bungalow is oriented with the long side facing south. During the winter, when the sun is low on the horizon, lots of sun gets in the big south-facing living room picture window, keeping the main floor quite warm. During the summer the sun is high enough that the overhanging eave blocks most of the direct sun, and the leaves on the front-yard trees do the rest of the job. The attic is well insulated, so with the house collecting sun our heating bill is quite low in the winter ($80 a month) even with a 40-year old gas furnace, and the place tends to stay cool in the summer.
posted by fimbulvetr at 8:36 AM on July 18, 2022 [3 favorites]
posted by fimbulvetr at 8:36 AM on July 18, 2022 [3 favorites]
Double hung windows were *somewhat* effective when our AC was out, but open windows at night (when it could actually cool down) isn't a great idea in the city. In the winter, they have always been terrible.
Windows that pivot from the bottom are cat-killers. Bottom-hung window trauma or syndrome. They try to step over, get stuck at the waist, and the weight destroys their spine.
posted by a robot made out of meat at 9:02 AM on July 18, 2022
Windows that pivot from the bottom are cat-killers. Bottom-hung window trauma or syndrome. They try to step over, get stuck at the waist, and the weight destroys their spine.
posted by a robot made out of meat at 9:02 AM on July 18, 2022
A very old way of making "draftless" ventilation with a sash window is to cut a plank the exact width of the window, open the sash and wedge the plank across the opening. This allows ventilation through the top of the window opening, but no direct drafts.
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Had one of these in our front window for decades now. It still spins merrily every day while the little panels or capacitors on other solar toys have faded away to uselessness. A powerful photo flashgun will give it a real impulsive kick, too
posted by scruss at 9:10 AM on July 18, 2022
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a solar radiometer
Had one of these in our front window for decades now. It still spins merrily every day while the little panels or capacitors on other solar toys have faded away to uselessness. A powerful photo flashgun will give it a real impulsive kick, too
posted by scruss at 9:10 AM on July 18, 2022
Except that the actual research shows that specifically designing a house for winter sun doesn't really work in most climates, because winter in generally cloudier, when you need the sun in winter is on the days its cloudier and colder, and it often gets blocked by snow or rain. And cloudiness proceeds poor weather, preventing heat build up.
But for the tiny number of climate days and locations that are not snowy, cloudy, or rainy in the winter, it's fine.
Some numbers might be helpful because around here (New England) it seems like the opposite is true and most of the winter is clear, cold, sunny days that are occasionally punctuated by overcast weather and snow. Certainly locations where it's always snowing/raining/overcast during the winter would be the minority of locations, not the other way around.
posted by RonButNotStupid at 9:14 AM on July 18, 2022 [1 favorite]
But for the tiny number of climate days and locations that are not snowy, cloudy, or rainy in the winter, it's fine.
Some numbers might be helpful because around here (New England) it seems like the opposite is true and most of the winter is clear, cold, sunny days that are occasionally punctuated by overcast weather and snow. Certainly locations where it's always snowing/raining/overcast during the winter would be the minority of locations, not the other way around.
posted by RonButNotStupid at 9:14 AM on July 18, 2022 [1 favorite]
high-rise buildings stabilised by an electrically motorised pendulum in the foundations...
The fail-safe mode for those is to act as a passive rather than an active damper, less comfortable but the building shouldn't collapse.
posted by Lanark at 9:23 AM on July 18, 2022
The fail-safe mode for those is to act as a passive rather than an active damper, less comfortable but the building shouldn't collapse.
posted by Lanark at 9:23 AM on July 18, 2022
I guess it really comes down to whether adaptations to let the sun in during the winter are worth whatever compromises those adaptations create for keeping the sun out in the winter.
Around here we only clean the glass on our windows in the fall so that they let the maximum amount of light in during the winter and leave them dirty during the summer to slightly reduce the amount of light coming through.
posted by RonButNotStupid at 10:21 AM on July 18, 2022 [1 favorite]
Around here we only clean the glass on our windows in the fall so that they let the maximum amount of light in during the winter and leave them dirty during the summer to slightly reduce the amount of light coming through.
posted by RonButNotStupid at 10:21 AM on July 18, 2022 [1 favorite]
It's amazing to have such a huge wide-open window, or turn the handle and just have a little bit. I don't know why bugs aren't such a problem, but they'd certainly never work where I am in the US; I had a small opening in a window screen for the past couple nights and my whole family already has at least one mosquito bite each!
They actually make bug netting with adhesive, velcro, or magnetic attachment that can go on the outside of the window, so you can open use the window normally bite-free!
posted by wakannai at 10:57 AM on July 18, 2022
They actually make bug netting with adhesive, velcro, or magnetic attachment that can go on the outside of the window, so you can open use the window normally bite-free!
posted by wakannai at 10:57 AM on July 18, 2022
All the mass and ventilation in the world isn't going to help you if the air temperature never drops below desired room temperature over the course of the day.
An architect I knew as in the process of building his own residence which was a modernist design. Despite it being 107 degrees the day I visited and despite not yet having A/C, it was surprisingly comfortable on the main floor. The reason was that he had incorporated a tunnel from the living area up to the roof (three floors up) which had a skylight. With the low windows (along the ground popped open) that open skylight induced a draft through the first floor that was enough to blow papers off of table in the dining room. Honestly it was astonishing. Even though the air that was being drawn in was still very hot the effect was cooling. Obviously the second and (especially) third floors were murder but at least on the 3rd floor he had skylights that actually open upwards like a hatch for maximum ventilation. Additionally the south side of the house had white architectural panels mounted a foot away from the actual wall of the house. The sunlight hit those panels but the wall behind was completely shaded.
posted by drstrangelove at 11:40 AM on July 18, 2022 [2 favorites]
An architect I knew as in the process of building his own residence which was a modernist design. Despite it being 107 degrees the day I visited and despite not yet having A/C, it was surprisingly comfortable on the main floor. The reason was that he had incorporated a tunnel from the living area up to the roof (three floors up) which had a skylight. With the low windows (along the ground popped open) that open skylight induced a draft through the first floor that was enough to blow papers off of table in the dining room. Honestly it was astonishing. Even though the air that was being drawn in was still very hot the effect was cooling. Obviously the second and (especially) third floors were murder but at least on the 3rd floor he had skylights that actually open upwards like a hatch for maximum ventilation. Additionally the south side of the house had white architectural panels mounted a foot away from the actual wall of the house. The sunlight hit those panels but the wall behind was completely shaded.
posted by drstrangelove at 11:40 AM on July 18, 2022 [2 favorites]
fimbulvetr --- I lived in an airplane bungalow that was like that. Deep eaves shaded the windows during the summer but allowed tons of light through in the wintertime, warming the rooms on the south side of the house quite nicely. Additionally the way the windows were situated meant there was naturally-induced crossflow. If there was a breeze of any kind the effect was supercharged. Plus on the second floor there was what was essentially a summer sleeping room--- tall windows lined three of the walls. Combined with the draft it actually started to feel cool at night even during the "dog days" of summer.
posted by drstrangelove at 11:44 AM on July 18, 2022
posted by drstrangelove at 11:44 AM on July 18, 2022
Some numbers might be helpful because around here (New England) it seems like the opposite is true and most of the winter is clear, cold, sunny days that are occasionally punctuated by overcast weather and snow. Certainly locations where it's always snowing/raining/overcast during the winter would be the minority of locations, not the other way around.
Large parts of Europe (including most big cities except say Rome/Athens/Madrid) are farther north than the USA, and it's not just the conveyor belt of European windstorms that makes it dark in winter - it's the latitude that means it can be night-time by 4pm or earlier. I grew up in what's called the "Sunny South-East" of Ireland, and it only gets about 2 hours of daily sunshine in midwinter. It's a bit "Four Yorkshiremen", but my Finnish friend grew up 300km north of the Arctic Circle, and didn't see sun for months, so sunlight doesn't work everywhere.
posted by kersplunk at 12:22 PM on July 18, 2022 [2 favorites]
Large parts of Europe (including most big cities except say Rome/Athens/Madrid) are farther north than the USA, and it's not just the conveyor belt of European windstorms that makes it dark in winter - it's the latitude that means it can be night-time by 4pm or earlier. I grew up in what's called the "Sunny South-East" of Ireland, and it only gets about 2 hours of daily sunshine in midwinter. It's a bit "Four Yorkshiremen", but my Finnish friend grew up 300km north of the Arctic Circle, and didn't see sun for months, so sunlight doesn't work everywhere.
posted by kersplunk at 12:22 PM on July 18, 2022 [2 favorites]
Are those massive all glass pencil tower blocks going to be habitable without power?
It won't be the temps that will make them uninhabitable. It'll be the elevators not working and that'll apply to a lot of the non-glass towers as well. Having hiked up and down 17 floors in an uncooled stairwell (they never have a/c) I can tell you I'd bail out of high-rise living pretty fast if there was a never ending elevator outage.
posted by srboisvert at 12:44 PM on July 18, 2022 [1 favorite]
It won't be the temps that will make them uninhabitable. It'll be the elevators not working and that'll apply to a lot of the non-glass towers as well. Having hiked up and down 17 floors in an uncooled stairwell (they never have a/c) I can tell you I'd bail out of high-rise living pretty fast if there was a never ending elevator outage.
posted by srboisvert at 12:44 PM on July 18, 2022 [1 favorite]
I wish the video would have gone more into multi-window, mutli-room and multi-floored buildings to create maximal airflow. She sort of touched on it in the comments, but kept her model and main presentation a bit too simple. It's actually kind of hard to achieve noticeable airflow if it's not a windy day.
posted by The_Vegetables at 1:51 PM on July 18, 2022
posted by The_Vegetables at 1:51 PM on July 18, 2022
Except that the actual research shows that specifically designing a house for winter sun doesn't really work in most climates, because winter in generally cloudier, when you need the sun in winter is on the days its cloudier and colder,
The point isn't that you are guaranteed to have sun and thus be warm in winter - the point is that you are guaranteed to NOT have sun ingress in summer and will stay cool, while allowing generous ingress of sun in winter whenever it's available.
Without utilizing any artificial heating, if you get lucky and have a sunny day, the interior temperature at 9pm at night is still 22°C throughout the living areas, while it's 12°C outside, which is a bit of a shock stepping outside.
posted by xdvesper at 4:58 PM on July 18, 2022 [1 favorite]
The point isn't that you are guaranteed to have sun and thus be warm in winter - the point is that you are guaranteed to NOT have sun ingress in summer and will stay cool, while allowing generous ingress of sun in winter whenever it's available.
Without utilizing any artificial heating, if you get lucky and have a sunny day, the interior temperature at 9pm at night is still 22°C throughout the living areas, while it's 12°C outside, which is a bit of a shock stepping outside.
posted by xdvesper at 4:58 PM on July 18, 2022 [1 favorite]
As somebody living in a place where it's at least 32°C every single day (and very humid at that), it's totally possible to design houses that can keep cool in such a climate. Air wells like drstrangelove mentioned are one common feature, as well as various other methods to increase shade and improve air flow. You can read up on tropical architecture to get some ideas.
The problem the world is having now, though, is the "change" part of climate change... Like what others said above, the issue is that the parts of the world having heat waves now were not designed to deal with such weather. The infrastructure and environment just isn't suitable. We could (and eventually will) adapt and change things to handle such climate extremes, but until we do so, there's going to be a lot of discomfort, not to say deaths especially among poorer folks. Dealing with this aspect of climate change isn't really a technological problem, its a sociological one.
posted by destrius at 6:51 PM on July 18, 2022 [1 favorite]
The problem the world is having now, though, is the "change" part of climate change... Like what others said above, the issue is that the parts of the world having heat waves now were not designed to deal with such weather. The infrastructure and environment just isn't suitable. We could (and eventually will) adapt and change things to handle such climate extremes, but until we do so, there's going to be a lot of discomfort, not to say deaths especially among poorer folks. Dealing with this aspect of climate change isn't really a technological problem, its a sociological one.
posted by destrius at 6:51 PM on July 18, 2022 [1 favorite]
at 9pm at night is still 22°C throughout the living areas, while it's 12°C outside, which is a bit of a shock stepping outside.
Well 12C is still shorts weather, on the lower end of 'perfect weather', and so few people in the world would even run mechanical heat, but even though I disagree with the number I agree with the concept. There are some days that are -3to -5C and the bright sun can keep the indoor temperature close to 22C. I'm just disagreeing on the number of days and places, and value of any expense spent to support those days.
posted by The_Vegetables at 7:18 AM on July 19, 2022
Well 12C is still shorts weather, on the lower end of 'perfect weather', and so few people in the world would even run mechanical heat, but even though I disagree with the number I agree with the concept. There are some days that are -3to -5C and the bright sun can keep the indoor temperature close to 22C. I'm just disagreeing on the number of days and places, and value of any expense spent to support those days.
posted by The_Vegetables at 7:18 AM on July 19, 2022
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