Awnings: a simple cooling tech we apparently forgot about
Summary
TLDRThis script makes a case for the revival of window awnings, once a popular architectural feature to keep homes cool by blocking direct sunlight. It discusses the science behind how windows contribute to heat gain and the benefits of awnings in reducing this effect. The speaker also touches on the historical popularity of awnings, their decline with the advent of air conditioning, and the potential energy savings they offer today. The script calls for more research into their effectiveness and suggests reconsidering restrictions on their use.
Takeaways
- đ Window awnings were once popular but have fallen out of fashion, despite their practical benefits.
- đ Awnings help keep homes cool by blocking direct sunlight from windows, reducing the greenhouse effect and heat gain.
- đĄ Windows, while letting in natural light, can also be a major source of heat gain, especially when the sun shines through them.
- đĄ Traditional structures like covered porches and galleries were designed to shade windows and keep interiors cooler.
- đ° Articles from the 1920s highlight the importance of awnings for comfort and aesthetics, suggesting they were a significant home feature.
- đĄïž Awnings can significantly reduce the need for cooling in homes, with one study showing a 20% reduction in annual cooling energy needs.
- đž The energy savings from awnings can also translate into cost savings on electricity bills.
- đĄ Awnings can be a stylish and personal touch to a home, adding character and charm.
- đ The script calls for more research on the effectiveness of window awnings, as current data is limited and often biased.
- đ Awnings do have some drawbacks, such as making interiors darker and potentially attracting pests, but these can be managed or mitigated.
Q & A
What is the main purpose of window awnings?
-The main purpose of window awnings is to provide shade and reduce heat gain in a building, especially during hot summer months. They help in preventing the greenhouse effect by blocking direct sunlight from entering through windows.
Why have window awnings fallen out of fashion?
-Window awnings have fallen out of fashion primarily due to the advent of mechanical air conditioning, which made the passive cooling techniques like awnings less necessary. Additionally, changing fashion trends and the perception that homes with awnings lacked modern amenities like air conditioning contributed to their decline.
What is the greenhouse effect in the context of buildings?
-In the context of buildings, the greenhouse effect refers to the process where sunlight passes through transparent windows and into an enclosed space, heating up the interior. This effect can be mitigated by using window awnings to block direct sunlight.
How do windows contribute to heat gain in a house?
-Windows contribute to heat gain in a house by allowing sunlight to pass through and land on interior surfaces like flooring and furniture. These surfaces absorb the sun's light energy and re-radiate it as heat energy, increasing the indoor temperature.
What role did awnings play in the design of historic buildings?
-In historic buildings, awnings played a crucial role in shading windows and keeping the interiors cool. They were used in structures like grand covered porches and galleries in French Quarter buildings to prevent the greenhouse effect and maintain a comfortable temperature inside.
What benefits do window awnings offer in terms of energy efficiency?
-Window awnings offer significant energy efficiency benefits by reducing the need for air conditioning during hot weather. They can help in reducing the annual cooling energy needed by up to 20%, thereby saving on electricity bills.
What are the potential drawbacks of using window awnings?
-Potential drawbacks of using window awnings include making the interior of the home darker during the day, requiring maintenance like cleaning and potential issues with pests finding shelter under the awning. Additionally, the aesthetic appeal might not be universally liked.
How do window awnings compare to other shading solutions like exterior roller shutters or blinds?
-Window awnings offer a simpler and more flexible solution compared to exterior roller shutters or blinds. While shutters and blinds can also block sunlight, they often block the view when in use, whereas awnings allow for a clear view outside. Awnings can also be easily retracted when not needed.
What is insolation and why is it important in the context of window awnings?
-Insolation refers to the heat gain from solar irradiance in the context of buildings. It is important because it represents the amount of heat energy that enters a building through windows, contributing to the need for cooling. Window awnings help in reducing insolation by blocking direct sunlight.
What role do window awnings play in managing the solar heat gain coefficient (SHGC) of windows?
-Window awnings can effectively manage the solar heat gain coefficient of windows by blocking sunlight from hitting the glass, making it unnecessary to have windows with low SHGCs. This allows homeowners to use windows best-suited for winter heat gains and block the sun in the summer with an awning.
Outlines
đĄ Rediscovering Window Awnings
The speaker reflects on the past popularity of window awnings and argues for their comeback. Despite falling out of fashion, awnings are practical for keeping homes cool by blocking sunlight, reducing heat gain. The historical use of awnings is highlighted, showing how they helped maintain cooler interiors and protect homes from the sun.
đïž Awnings in the Urban Landscape
Awnings were once a staple in cities like Chicago, providing shade and reducing indoor temperatures. The decline in their use is attributed to air conditioning and changing aesthetics. Awnings helped homes appear outdated, leading to their removal. However, they offer aesthetic and practical benefits, such as energy savings.
đ Balancing Heat and Cooling
Modern windows have improved in blocking heat, but awnings offer a versatile solution by providing shade without sacrificing winter warmth. The speaker shares data showing that awnings can significantly reduce cooling energy needs, making them a cost-effective addition to homes.
đ§ Challenges and Innovations
Awnings can make interiors darker and require maintenance. Modern innovations, like retractable and smart awnings, offer flexible solutions. While there are challenges, such as pest attraction, awnings remain a viable option for reducing heat gain and allowing natural light.
đ© Awnings: A Cool Comeback
The conclusion emphasizes the potential of awnings to reduce cooling costs and improve home comfort. Despite their historical significance, more research is needed to understand their benefits fully. Awnings offer a simple, effective way to combat heat while adding character to homes.
Mindmap
Keywords
đĄWindow Awnings
đĄGreenhouse Effect
đĄInsolation
đĄAir Conditioning
đĄSolar Heat Gain Coefficient (SHGC)
đĄEnergy Efficiency
đĄFashion and Trends
đĄHome Design Techniques
đĄHeat Domes
đĄHOA (Homeowners Association)
đĄMaintenance
Highlights
Window awnings, once popular, have fallen out of fashion but offer significant benefits in keeping homes cool.
Awnings can reduce the heat gain in homes during summer months by blocking direct sunlight through windows.
The greenhouse effect occurs in homes when sunlight passes through windows and is absorbed as heat energy by interior objects.
Awnings provide a passive cooling method, reducing the need for air conditioning and thus saving on energy costs.
Historically, awnings were a selling point for homes, adding both aesthetic and functional value.
Awnings can prevent the fading of wallpaper and carpets by blocking the sun's harmful UV rays.
Innovations in window coatings have reduced heat gain, but awnings still offer additional benefits in summer.
The introduction of mechanical air conditioning has diminished the perceived need for passive cooling methods like awnings.
Awnings can be a stylish and personalized home accessory, offering both form and function.
Modeling data suggests that adding window overhangs can reduce annual cooling energy needs by up to 20%.
The choice between high and low solar heat gain coefficient windows can be mitigated by using awnings seasonally.
Awnings can be easily installed and are a cost-effective solution for managing solar heat gain.
Awnings are not only practical but can also enhance the architectural appeal of a home.
Modern materials and designs offer new possibilities for awnings, including retractable and smart awnings.
Awnings can be a sustainable solution to increasing energy efficiency in homes.
The lack of current research on the effectiveness of window awnings suggests a need for further study.
Awnings can be a simple yet effective way to combat the rising temperatures and energy demands in homes.
The potential for awnings to be integrated into building codes and HOA regulations could increase their adoption.
Awnings offer a classic and customizable solution for managing solar heat gain in various climates.
Transcripts
You ever reach way back into your brain
and uncover something from the not-too-distant past that seems weirdly obvious yet isnât popular anymore?
Thatâs right, Iâm talking about window awnings!
You used to see these everywhere, especially on those cute brick ranches kitty corner to the house where you grew up -
Iâm sure thatâs a universal experience.
But lately, theyâve fallen out of fashion.
And I would like to make the case that we should get them back.
Quick programming note, Iâm not gonna be recommending any specific kind of awning or product line or anything like that.
I am not here to sell you anything
...YouTube ads notwithstanding...
though I do like spreading ideas.
And awnings are one of those ideas that our ancestors figured out but as far as I can tell we just decided weâre too cool for these days.
Which is ironic because window awnings keep you cool.
Thatâs their point! Or at least, a central point.
See, we like windows.
[WIndows XP error sound] Maybe not that kind, but that kind is pretty universally liked.
They let in natural light and allow us to look outside and see things.
But windows are also great big holes in walls which we only plugged with thin sheets of glass.
While they have gotten surprisingly good over the years at keeping heat energy from moving through them,
theyâre still nowhere near as good as the thick walls which surround them.
And, hereâs the important bit to this video,
they become a major source of heat gain when the sun shines through them.
Ever heard of the greenhouse effect?
That doesnât just happen in greenhouses, it happens any time the sunâs energy makes it through a transparent window and into an enclosed space.
Like your house.
Once sunlight makes its way into your home, it lands on the stuff inside like flooring, furniture, et cetera.
That stuff absorbs the sunâs light energy which is then re-radiated into your home as heat energy.
This heat gain from solar irradiance, in the context of buildings, is called insolation.
Not insulation - but insolation.
Donât look at me, I just work here.
Thanks to recent innovations in coatings on the glass, a lot of this energy is reflected away and kept out of your home.
But, fun fact, the sun is extremely powerful so even with really fancy windows thereâs a lot of energy getting inside that ultimately becomes heat.
Donât take my word for it, just ask a cat.
In the winter months this warmth can be a pretty nice benefit,
but in the summer months - it sucks.
And our ancestors knew this.
They figured out that if you designed a structure so that the windows couldnât be in direct sunlight,
then there would be no greenhouse effect and the interior of that structure would stay much cooler.
Those grand covered porches you see on fancy old houses throughout much of the Southern US werenât just for enjoying the breeze,
they kept the windows entirely shaded.
In fact they kept pretty much the entire structure shaded.
And it wasnât just plantation houses - the galleries attached to historic French Quarter buildings also help keep the buildings cool.
Notice how the building is in direct sunlight here but almost the entire structure (other than the roof) is in shade.
Of course, those examples have multiple purposes.
I canât earnestly say that shading windows was âthe pointâ of a covered porch.
It also created a pleasant outdoor space and protected windows and doors from the elements, allowing you to leave them open in a rainstorm.
But we did recognize the value of that coverage.
So much so that in the not-too-distant past,
there were popular products for your home which provided the shade and cover of an opulent wraparound porch but with minimal materials and easy installation.
What products, you ask?
Awnings!
It appears these really came into vogue in the 1920âs.
This 1927 article in Building Age and National Builder comes out swinging:
âA Beautiful home which is devoid of awnings resembles a well dressed man without a necktie.
The awnings give that finishing touch, just the last point to complete the proper taste.â
Seems like the author really likes awnings!
But why?
Itâs all about keeping comfortable!
âAn awning on the porch permits the use of the porch when the hot afternoon sun is shining.
They will keep the porch shady and pleasant, and this also reduces the temperature of the rooms adjoining the porch.â
And hereâs my favorite part:
âThe fact that the awning excludes the sun from the window glass is quite an important asset in reducing the temperature of the room,
and in preventing the fading of wall paper and carpet.â
Sure seems like awnings are the catâs meow!
In 1925, Hal and Helen Davis wrote in Better Homes and Gardens
âAwnings - they have such possibilities, such delightful possibilities, that foolish indeed is a house to go without them, if they can be afforded.â
Thatâs right, we just got called fools by the Davis family!
Honestly this article is a useful tool for understanding how they were spreading.
It even breaks down the differences in awning configurations by locale and the pros and cons of various types.
This used to be a big deal!
And they were a selling point for your home -
real estate firms are beginning to learn the value!
Plus theyâre just a fun accent piece.
I mean, who wouldnât want to flaunt their unusually picturesque nature with a cool set of Arabian Awnings?
The spears really sell it.
But hundred year old magazine articles are one thing and the real world is another.
How big were awnings really?
Well, if you dingle around on the olâ Streetview and visit practically any old Chicago neighborhood,
youâll find plenty of houses which still have exterior window awnings providing that overhang for shade, especially on South and West-facing windows.
You can see in this image how effective they are:
this side of the house is being hit with direct sunlight, but the awning is almost entirely shading the window below it.
Thanks to that awning, the old front room is staying much cooler than it would without it.
Many of these products also allowed you to leave windows open in the rain - at least if they were installed correctly and you had the right kind of window.
They offered a lot of benefits!
Yet despite remaining extant in various styles,
the functional purpose of window awnings seems to have almost entirely left the public consciousness.
Whyâd this happen?
Iâm gonna say itâs a mix of two factors: air conditioning and fashion.
The advent of mechanical air conditioning diminished the importance of the passive tricks we used to rely on to keep cool.
As more and more people started hooking up energy-consuming air conditioners to the power grid
(boy I hope it can keep up with all that⊠sorry wrong topic).
As more and more people got air conditioning, suddenly the temperature in their home was controllable.
And so long as those air conditioners were powerful enough to overcome the heat gain of solar irradiance,
the awnings that previously helped keep us cool in a heatwave didnât seem necessary any longer.
And, technically, they werenât.
So, fast forward a decade or two, and new homes are getting built without them.
No need for awnings when we can pump the heat right out!
That meant that all the older homes with awnings started to look dated.
And if thereâs one sin in the fashion world, itâs looking dated.
As you can tell I take this very seriously.
Beyond fashion, though, awnings on a home may very well have been a sign that the home didnât have air conditioning,
and Iâll bet many a realtor in the 1960âs suggested taking them down.
"No one wants a house with awnings," theyâd say, "those are for old fuddy duddies. And poor people."
And now, other than that one infomercial, awnings are largely forgotten.
But dang it, I think itâs time for us to consider bringing them back.
For one, I actually think window awnings are pretty cute.
Maybe not the aluminum ones that you still run across sometimes, though hey - they sure proved their longevity.
But there are so many different styles of awning out there, plus many more to be discovered.
And like those 1920âs people, I think window awnings offer a real way to put a personal touch on a home.
And whatâs cooler than a way to express yourself that also literally keeps you cool?
Thereâs a lot to like about them!
Heat waves would be a lot more manageable with window awnings keeping the sunâs heat outside your home,
and day to day they save money on electricity bills.
How much money?
Well, unfortunately, thatâs not the easiest thing to answer.
It's annoyingly hard to get an idea of how much heat energy is actually coming through a window when the sun shines through it.
It depends on so many factors: your location on the planet, the direction the window faces, the time of the year, time of day,
and of course the performance of the window itself all matter a lot.
Still, I wanted to give you some useful information so I reached out to someone who has access to modeling software which can predict the energy needs of a home.
They took a typical house in Chicago and ran some numbers for heating and cooling demand while tweaking a few variables.
Thereâs a lot of interesting stuff to cover here but what I want to highlight first is this:
Doing nothing to the house but adding window overhangs reduced the annual cooling energy needed by 20%.
Thatâs a big deal!
But youâll notice that other things had an impact, too.
And if you notice even harder, youâll see that those impacts were all double-edged.
In the past, Iâve mentioned Low-E windows.
Thatâs kind of a catch-all term and doesnât mean a whole awful lot on its own, but broadly it just means high-performance windows.
And one of a windowâs performance metrics is the solar heat gain coefficient.
You can think of this as the percentage of the sunâs heat energy that makes it through the glass.
There are windows on the market now with exceptionally low SHGCs: some windows donât even let a quarter of the sunâs energy through,
and those are great to have in warm climates where you rarely ever need to heat buildings.
But theyâre often not a great fit for us up North because over the course of a year we need more heat energy than we need cooling,
and blocking the sunâs free heat doesnât make much sense.
Notice that in our modeling,
swapping out just the South facing windows to a lower SHGC
dropped cooling demand a pretty similar amount to adding overhangs.
But look what it did to the heating demand.
It went up significantly because those windows are actually working against us in the winter.
Our winters suck and some free heat from the sun is a very welcome thing.
So thereâs a tradeoff to changing the windowâs thermal performance characteristics.
And have you noticed what the lowest total annual power figure came from?
Windows with high solar heat gain coefficients for free heating in the winter but which had overhangs to block sunlight in the summer.
Thatâs the beauty of awnings.
We donât have to make the choice between winter and summer performance when buying a window.
We could use a window best-suited for winter heat gains and then in the summer just block the sun from hitting it with an awning.
The reason why Iâm making this video now is that, well, it occurred to me that there isnât really a difference
between a properly-installed window awning and some of the rather advanced home design techniques we see today.
Those with lots of money to spend when designing their new custom homes might get fancy and install different window types.
One method Iâve talked about before is installing high heat-gain windows below an overhang so they provide that free heat in the winter but not in the summer.
And then use low-heat-gain windows elsewhere in the house.
Thatâs a cool idea but itâs a lot of work compared to slapping on an awning!
And the best thing about slapping on an awning (besides how fun that is to say) is that it can be done cheaply and anywhere!
Speaking of anywhere, hereâs a clunky voiceover edit.
Iâm worried that I fixated too much on the scenario we face here and not enough on warm and hot climates.
Because even if youâve got the best dang windows on the market with an SHGC of .2, five average-sized West-facing windows (Iâm calling 3 by 5 feet average)
are going to let in more than a kilowatt of heat for several hours every afternoon.
Thatâs not far off from running a space heater on high, and when itâs 100 degrees outside thatâs not the smartest move.
For giggles I decided to look at some new homes getting built around Phoenix, Arizona
and itâs frankly astonishing to me that in that climate thereâs apparently no focus paid on window overhangs.
Sure, back in the day we didnât have the fancy glass we do now,
but if window awnings were popular here in Chicago, where itâs really only hot 4⊠maybe 5 months of the year,
it seems to me like thereâs a lot of energy and money being wasted by not thinking of ways to keep windows in the shade.
Now, there's a couple of notes I want to add.
Both myself and the person who helped me with the modeling here are a bit skeptical of some of the data it spat out.
The impact of dark closed drapes when thereâs already a 2.5 foot overhang seems really high,
and the fact that those drapes by themselves are lowering cooling power more than the overhangs seemsâŠÂ impossible.
Drapes on the inside of a window donât stop sunlight from passing through the window glass.
At best, if theyâre very reflective, they can push some of the sun's energy back out
but having stood next to a West-facing window with a white roller shade, I can say from experience that that shade gets pretty stinking hot on summer afternoons.
It is always better to keep the sun from coming through the glass in the first place, that way there is no greenhouse effect,
so how this model is considering those factors seems a bit off.
Really, if thereâs one call to action I want to make here it would be that there needs to be more study on the effectiveness of window awnings.
Itâs quite strange how little information there is on this topic,
and most of what Iâve found are claims from awning manufacturers so Iâm not exactly taking them seriously.
But it does seem pretty obvious to me that if you can eliminate direct sunlight transmission through a window,
then youâre effectively turning any window into a North-facing window no matter which side of your house itâs on.
And that could make a dramatic difference in the warm parts of the year.
Unless youâre in the Southern hemisphere in which case, strike that - reverse it.
Now, itâs not like awnings donât come with any drawbacks.
Most obvious is that they make the interior of your home much darker during the day.
If the awning is made of a translucent material you could still get plenty of filtered light coming through the window,
but its entire purpose is to eliminate direct sunlight and if thatâs something you or your cat appreciates, well a proper awning is going to eliminate it.
Although, I am quite curious about the potential effectiveness of a transparent awning made from glass with a really low solar heat gain coefficient.
That might be a way to have the best of both worlds.
And it would leave your view of the sky mostly unimpeded.
Then thereâs maintenance.
The aluminum ones that still hang around were designed in response to the fiddle factor of fancy fabrics.
Those fabrics would fade with time and required periodic cleaning, and depending on the design of the support structure,
removing the fabric from the awning could be a pain in the butt.
A rigid awning made of aluminum mostly took care of these problems, and thatâs most likely why they started spreading.
Then again, materials science has improved dramatically since awnings went out of fashion,
and some fabric awnings can be selectively deployed.
A roller-awning can be retracted when you donât need or want it,
and donât look now but throw some Wi-Fi and actuators into the mix
and youâve got yourself a Smart Awning that could deploy exactly as much as needed and stay retracted on cloudy days or in inclement weather.
The last main drawback to awnings that IÂ can think of is pests.
Through providing shelter for your window youâre also providing shelter for living creatures, and while Iâd be pretty cool with a robinâs nest outside my window,
a wasp nest is less cool.
Then again, if the window is screened itâs not like that really matters all that much
but Iâve dealt with my share of wasp nests and usually itâs best to not have to deal with them.
But to be honest, all of those drawbacks seem pretty minor to me, and many of them arenât even a thing all the time.
I can tell you that I would freaking love some awnings on my home - particularly on the West side.
Iâm still doing that thing where I only run the air conditioning in the overnight hours
and one of the most interesting things that technique has revealed is the dramatic effect of the sun.
On cloudy days, even though it might be quite hot outside, my home only heats up by 5 or 6 degrees Fahrenheit over the course of the day.
But if itâs a sunny day at the same temperature, that just about doubles.
Of course, not all of that is heat from the windows - the atticâs also getting stupid hot from the sun, and so are the walls.
So itâs not easy to isolate that variable.
But I can say it is truly remarkable how quickly the rooms on the West side start to heat up once the sun reaches those windows.
Awnings arenât the only solution, of course.
Thereâs been a whole bunch of Europeans just champing at the commenting bit to let you know all about those exterior roller shutters theyâve had over there for a while.
Those are interesting, and theyâre starting to be sold here,
but Iâm curious to know how hot those shutters get in the sun.
When closed they seem to trap a bit of air between them and the window glass, so while I have no doubt theyâre blocking the sun,
it seems to me like the window will be getting quite warm as the shutters radiate their absorbed heat into that airspace.
Iâd rather have an awning, then that heat isnât trapped and I can still look outside!
Then there are exterior blinds. Iâm starting to see these spread, often on porches.
Theyâre basically the same idea as Rolladen but usually fabric and not integrated into the window frame or anything.
Again, those will absolutely do the job of blocking sunlight from hitting the window, but they also block the view when in use which awnings donât, Â
at least not the view out.
If I seem gung-ho about awnings, well I am!
I think theyâre cool and have been tragically overlooked for the past half-century.
Which brings me to one last thing.
I live in a townhome which means if I wanted to install window awnings, Iâd need to get the HOA involved.
And thatâs not fun.
So - circling back to that earlier call to action where IÂ said we should do more research on them,
if it turns out that window awnings actually could reduce a typical homeâs cooling costs by 20%,
then whaddya say we go ahead and neuter an HOAâs ability to forbid their installation?
Or, if that sounds too extreme, at the very least force HOAs to offer an assortment of approved styles and colors.
Something tells me weâre going to want to find more and different ways to keep cool as these heat domes keep happening,
and if something as simple as a window awning is as useful as it seems to be, uhh we should probably encourage their use.
Alright, well thatâs it!
If anyone out there is involved in evaluating building energy codes and all that fun stuff, please chime in with any info you might have on this topic.
I really didnât find anything specifically about awnings and how much they could reduce cooling costs,
and from what Iâve heard there really isnât much attention paid to the effects of window overhangs at all outside of hyper-nerd circles.
If window awnings were helpful before air conditioning, then surely theyâre still helpful now.
And given how a lot of new housing stock, even in places like Arizona, is getting built without window overhangs at all,
either these new windows are miraculous marvels or we just kinda forgot the tricks of the past.
Hereâs to giving some of them another go.
â« blisteringly smooth jazz â«
âŠpretty universally liked.
They let in natural light and allow us to look outside and see things!
But⊠what was that?
Probably nothing you heard but I stopped anyway.
Thereâs gotta be two good takes in there.
I forgot how to tie a tie, I had to look it up!
Itâs been too long.
Those grand covered porches you see on fancyâŠ
I am restarting this line.
An awning on the porch permits the use of the porch when the hot afternoon sun is shining.
They will keep the porch shaft and pleasant,
and this also reduces the temperature - I can skip the rest of this line because IÂ already recorded the thing with the tie.
That might be a way to have the best of both worlds.
And it wood pfftehhâŠ.
[falls apart]
[angry sigh]
OK, so we gotta come up with some sort of pitch.
Oooh, pitch.
Baseball!
Awnings: like a baseball cap for your house!
Or maybe....
AWWWWWW
nings.
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