awnings

[loutfard]

"Awnings and air conditioning can be combined, resulting in a significant decrease in energy consumption. Several studies show that awnings can reduce the energy use of air conditioning systems by one-third to more than one-half of the total, yielding energy savings that surpass those of more expensive double-pane or low-emissivity glazing (which is designed to block UV rays). Nowadays, windows are larger than ever, and so awnings can obtain very good results for a relatively small investment."

from https://solar.lowtechmagazine.com/2025/ ... -the-home/

[chenda]

I've increasingly seen more businesses install awnings, especially cafes, takeaways etc. 100 years ago they would have been ubiquitous on every high street.

[7Wannabe5]

Awnings can be structurally tricky, and they can make a room seem permanently cast into gloom. They also limit landscaping possibilities. Deciduous tree plantings, if chosen and placed in manner to avoid difficulties with roots, can provide many of the same benefits while allowing for more sunlight and solar gain in winter. Another option might be creating a seasonal structure for quick growing annual vines. The design could be as simple as planting flowering early spring bulbs underneath windows, and then securing a lattice-work for colorful varieties of pole or runner beans.

[jacob]

Some of the houses in my hood still have the original(?) awnings. They are made out of metal (tin?) and covers the top 1/3 of the window making a little roof. Another benefit is that they protect the window itself from rain/weathering. I suspect that is closer to the real reason because some houses have them on all four sides.

[Stasher]

I wonder if awnings are less in use due to the very large advancements in window technology, solar gain and heating in summer is wildly reduced with triple pane modern windows. Now a modern window using a good set of blinds in summer is all one needs to feel no high point of summer heat concerns in their home.

[grundomatic]

Brad Lancaster's book (volume 2, probably) has a formula to determine the optimal overhang length based on one's latitude, balancing solar gains in the winter and shading windows in the summer.

[theanimal]

At my mom’s house, we had canvas awnings that were installed in the spring and taken down during the fall on the largest of our south facing windows. It kept the room a lot cooler, but it was another maintenance task in having to put them up and take them down, keep the fabric clean, and have somewhere to store it (or pay someone to do so). I don’t think my mom has done it for 15 years or so now.

[AxelHeyst]

I wonder if awnings are less in use due to the very large advancements in window technology, solar gain and heating in summer is wildly reduced with triple pane modern windows. Now a modern window using a good set of blinds in summer is all one needs to feel no high point of summer heat concerns in their home.

Awnings are less in use because you can just throw air conditioning at the problem and for many decades no one cared about how much energy it took to cool the neat-looking architectural solar ovens we built. Now that owners are beginning to care about HVAC as a percentage of Operating Expenses (ETA as well as capital expenses - with sufficient shading devices you can pay a little bit more for 'awnings' and pay a lot less for cooling equipment), and some are beginning to care about (the optics of) high carbon footprints, the 'cutting edge' of high performance buildings are going big on 'awnings' aka exterior solar shading devices. In my old firm we had a whole gaggle of nerds whose main job was doing analysis on optimum exterior solar shading geometry - in addition to the higher performance windows.

Higher performance windows are *mostly* about increased R-value, which does not help with solar gain but rather helps with air temperature differences (it's really hot outside or its really cold outside). There are coatings etc that help with solar gain - much better than old school windows - but nowhere near as effective as exterior solar shading.

Interior blinds are kind of a problem because windows are mostly invisible to solar radiation, but opaque to heat radiation. So the solar radiation comes in, heats up the blinds, which radiate back towards the window, which trap the heat.

It all depends on climate and orientation, of course. In mild climates shade isn't that important with high performance windows. In more extreme environments (and heads up, folks who live in previously-mild-but-not-so-much-anymore climates), exterior solar shading is in the process of making a comeback.

Also, awnings generally are going to have a lower energy/cost/carbon footprint for manufacturing than high performance windows. An ideal system might be a 'standard' dual pane window will well designed simple awning. Overall lower cost and materials/resource consumption etc.

[AxelHeyst]

Also, a reason not to have a super heat blocking coating on your window to prevent summer time solar gain is because… it’d block wintertime solar heat gain, which is desirable.

Awnings for the win, in other words. Great tech. We used to be good at them because we didn’t have mechanical cooling. Then we lost the competence because we didn’t have to be good at it. We’re picking the skill back up, slowly. A great example of advanced retroadaptics.

[chenda]

It a very hot climate you are probably better off minimising windows and focusing on shade and ventilation, and ensuring you have high thermal mass. A lot of traditional North African architecture is ideal for this. Blank external walls with the rooms focusing on an interior courtyard for shade, privacy and some lighting. Also see the Caribbean vernacular verandah style dwellings.

[jacob]

Interior blinds are kind of a problem because windows are mostly invisible to solar radiation, but opaque to heat radiation. So the solar radiation comes in, heats up the blinds, which radiate back towards the window, which trap the heat.

But here's a trick!

Cover part of the window by taping up the inside with aluminum foil with no air space in between (very important!). In the winter, replace with sheets of bubble wrap (never mind the airspace). We used this with great effect in the RV. We've also used it around the house. It's more effective than those window-wrapper-covers on can buy at home improvement stores.

[theanimal]

In the winter, replace with sheets of bubble wrap (never mind the airspace). We used this with great effect in the RV. We've also used it around the house. It's more effective than those window-wrapper-covers on can buy at home improvement stores.

Why do you use bubble wrap versus plastic sheeting or equivalent?

[jacob]

Because it's like two layers of plastic sheeting with trapped air? It's also what I have.

[Jean]

Nearly every house in switzerland have outside cover and inside shade on every windows. You can play with them to adapt to weather condition. I think it's was like that for at least 60 years, because there where already old outside cover when i was a kid.
I thought it was standard in all the west.

[jacob]

@Jean - I suspect a lot or maybe just some of those Swiss awnings have to do with "the Swiss redoubt". It's a clever idea. OTOH, I can tell you that being behind one of those aluminum shields during a big heat wave was rather hellish.

[loutfard]

Why do you use bubble wrap versus plastic sheeting or equivalent?

This was also what I did at my wife's rental apartment in the Baltics at the time. That combined with thick curtains very significantly improved the heating situation there...

[Jean]

They are traditionnaly made of wood, and have built in ventilation.
Aluminium ones without ventilation have some downsides.

[bryan]

I must say, my 19-teens house in Alabama has great eave overhang design for the south wall, windows. In the summer, most of the wall is in the eave's shadow. Not so in the winter.

The east and west windows are where I have to be mindful of opening/closing curtains. Awnings would help somewhat for those windows. I'm considering replacing my windows with European-style tilt and turn windows, so am curious what shading options might work best.

As a tangent, tinting my van's windows with some ceramic window tint (maybe even just 50%) has gone way up on my list of projects this summer.

[AxelHeyst]

For anyone interested in adding a little bit of 3d modeling and useful animation to their skillz stack, a fun project in Blender (blender.org) is to model your house or the exterior wall of your house in question, and then load up the sun-path plugin which allows you to cast shadows for any moment in time during the year. You enter in your lat/long and make sure the geometry is pointed in the correct direction wrt north. Then just model different awning/shading geometries so that you get good shade in warm months and good sun in cool months. Python does all the trig for you.

[black_son_of_gray]

No Math Alternative: Some tape, string, a protractor, (possibly) a stepladder, and suncalc.org

Easy Math Version: suncalc.org, a measuring tape, and some junior high level geometry.