By Adriana Zuniga-Teran who works at the School of Geography, Development and the Environment and the Udall Center for Studies in Public Policy at The University of Arizona. Her research lies at the intersection of urban planning, sustainability, and environmental governance, focusing on transformations of urban infrastructure toward nature-based solutions. Originally published at The Conversation.
Modern buildings tend to take electricity and air conditioning for granted. They often have glass facades and windows that can’t be opened. And when the power goes out for days in the middle of a heat wave, as the Houston area experienced in July 2024 after Hurricane Beryl, these buildings can become unbearable.
Yet, for millennia, civilizations knew how to shelter humans in hot and dry climates.
As an architectural designer and researcher studying urban resilience, I have examined many of the techniques and the lessons these ancient civilizations can offer for living in hotter and drier conditions.
With global temperatures rising, studies show that dangerously hot summers like those in 2023 and 2024 will become increasingly common, and intense storms might result in more power outages. To prepare for an even hotter future, designers today could learn from the past.
Sumerians: Keeping Cool Together
The Sumerians lived about 6,000 years ago in a hot and dry climate that is now southern Iraq. Even then, they had techniques for managing the heat.
Archaeologists studying remnants of Mesopotamian cities describe how Sumerian buildings used thick walls and small windows that could minimize heat exposure and keep indoor temperatures cool.
The Sumerians built their walls and roofs with materials such as adobe or mud that can absorb heat during the day and release it during the nighttime.
They also constructed buildings right next to each other, which reduced the number of walls exposed to the intense solar radiation. Small courtyards provided lighting and ventilation. Narrow streets ensured shade throughout the day and allowed pedestrians to move comfortably through the city.
Ancient Egyptians: Harnessing the Wind
The ancient Egyptians also used materials that could help keep the heat out. Palaces were made of stone and had courtyards. Residential buildings were made of mud brick.
Many people also adopted a nomadic behavior within their buildings to escape the heat: They used rooftop terraces, which were cooler at night, as sleeping quarters.
To cool buildings, the Egyptians developed a unique technology called the mulqaf, which consists of tall wall openings facing the prevailing winds. These openings act as scoops to capture wind and funnel it downward to help cool the building. The entering wind creates air circulation that helps vent heat out through other openings.
The mulqaf principle could also be scaled up to cool larger spaces. Known as a wind catcher, it is currently used in buildings in the Middle East and Central Asia, making them comfortable without air conditioning, even during very hot periods.
Ancient Puebloans: Working with the Sun
Civilizations on other continents and at other times developed similar strategies for living in hot and dry climates, and they developed their own unique solutions, too.
The Puebloans in what today is the U.S. Southwest used small windows, materials such as mud brick and rock, and designed buildings with shared walls to minimize the heat getting in.
Puebloan cliff dwellings at Mesa Verde offered protection from the elements and, because of their orientation, protection from direct Sun in summer. Andreas F. Borchert, CC BY-SA
They also understood the importance of solar orientation. The ancient Puebloans built entire communities under the overhang of south-facing cliffs. This orientation ensured their buildings were shaded and stayed cooler during the summertime but received sunlight and radiated heat to stay warmer during the wintertime.
Their descendants adopted similar orientation and other urban-planning strategies, and adobe homes are still common in the U.S. Southwest.
Muslim Caliphates: Using Every Drop of Rain where It Falls
Modern water management is also rarely designed for dry climates. Stormwater infrastructure is created to funnel runoff from rainstorms away from the city as fast as possible. Yet, the same cities must bring in water for people and gardens, sometimes from faraway sources.
Landscaping in the Mosque of Cordoba, Spain, was designed to funnel rainwater where needed for irrigation. Adriana Zuniga
During the eighth century, the Muslim caliphates in arid lands of northern Africa and the south of Spain designed their buildings with rainwater harvesting techniques to capture water. Runoff from rainfall was collected throughout the roof and directed to cisterns. The slope of the roof and the courtyard floor directed the water so it could be used to irrigate the vegetated landscapes of their courtyards.
Modern-day Mendoza, Argentina, uses this approach to irrigate the plants and trees lining its magnificent city streets.
Mayans and Teotihuacans: Capturing Rainwater for Later
At the city scale, people also collected and stored stormwater to withstand the dry season.
The ancient Teotihuacan city of Xochicalco and many Mayan cities in what today is Mexico and Central America used their pyramids, plazas and aqueducts to direct stormwater to large cisterns for future use. Plants were often used to help clean the water.
Large cisterns like this one in Xochicalco, a Teotihuacan community in what is now Mexico, were used to capture and store rainwater. Adriana Zuniga
Scientists today are exploring ways to store rainwater with good quality in India and other countries. Rainwater harvesting and green infrastructure are now recognized as effective strategies to increase urban resilience.
Putting These Lessons to Work
Each of these ancient cultures offers lessons for staying cool in hot, dry climates that modern designers can learn from today.
Some architects are already using them to improve designs. For example, buildings in the northern hemisphere can be oriented to maximize southern exposure. South-facing windows combined with shading devices can help reduce solar radiation in the summer but allow solar heating in winter. Harvesting rainwater and using it to irrigate gardens and landscapes can help reduce water consumption, adapt to drier conditions and increase urban resilience.
Retrofitting modern cities and their glass towers for better heat control isn’t simple, but there are techniques that can be adapted to new designs for living better in hotter and drier climates and for relying less on constant summer air conditioning. These ancient civilizations can teach us how.
35 comments
Comments are closed.
Unfortunately, methods that rely on nighttime coolness might not work so well in the new climate catastrophe era.
https://theconversation.com/too-hot-to-sleep-nights-are-warming-faster-than-days-as-earth-heats-up-186958
One thing that we will hear of more and more will be passive design. The buildings here used that principal though we seem to have mostly forgotten it. The worse example of modern design may be McMansions due to their wasteful use of materials and their often huge windows mean that it is only viable to live in them with air-con for the summer and heating for the winter. Of course this is predicated on a plentiful, cheap reliable supply of energy which as time goes on may very well be not so plentiful, expensive and unpredictable to boot. So if increasing heat does not drive us underground, we will have to make more intelligent choices with buildings. Not only the materials used but their orientation and the possibility of planting trees and shrubbery to shield the worse of the heat away from buildings. And we will have to be more like those Muslim hydraulic engineers who did not miss a trick and put any rainfall to intelligent use. I once thought of a story-line of people arriving in a bus to a McMansion suburb where each family stayed in one overnight and tried to live the early 21st century elite lifestyle. The story reveals in the end that that suburb is a sort of museum park where people learn of the incredible wastefulness of our lives before going back to the real world outside the park where everybody lives in humble cottages, windmills, water tanks, etc. with an appreciation of how they got to be brought to such a humble way of living.
I should imagine McMansion owners would have ground source heat pumps by then, because its expensive and shows others just how green and wealthy they are. With some thick reflective curtains up in the windows the cooling might be viable and all powered by solar!
I helped build a house in the UK that does not need heating or cooling. The house is airtight which is not good for condensation or virus transfer. The air exchange heat pump is used only to provide air flow to prevent this.
an commercial-grade whoke house filtration system would fix air quality issues (not just viruses….but VoC, etc)
but that costs $$$$$ anc only as good as the filters used
One option: Lower tech and lower cost, use an attic exhaust fan.
Supplement with a whole-house exhaust fan.
Solar powered to make it more efficient.
Not if there is radon. I lived in an old Irish house for a year and you just wore a thick sweater (excellent ventilation, even with closed windows) and watched TV in the room with a fireplace. Heated while you were there. Or pop down to the pub for a pint where it always was cheery and warm.
Also indoor trace gas pollution from cooking, plastics, etc., are not easily filtered out.
At least presently, most McMansion owners in the U.S. seem to revel in being able to show that they don’t conserve energy at all. That is a form of conspicuous consumption.
As an outsider, this was my impression of most of US society, not just McMansions. Icy cold AC settings in malls or offices in summer that force you to bring a jacket or gloves. Giant oil furnaces for heating large buildings, with no individual room adjustments and only two settings – off or full blast – meaning the only way to regulate temperatures is to open windows (in the middle of winter). Ever bigger and less practical SUVs and offroad pickups, with abysmal fuel efficiency, that only ever see suburban or commuting duty. The list goes on.
I was brought up to turn the lights off behind me at night if I was the last person leaving a room. A lot of Americans I know find this idea ridiculous.
Is there a passive design approach that deals with mold? Most of the America south will be a wasteland without dehumidification. Mold blooms aggressively when it’s humid, even at modest indoor temperatures in the 70s F (don’t ask how I learned this). While you can try to periodically (at least weekly) wipe down mold on every single surface in a house, I think this quickly is a losing battle.
Our House in Nigeria, Hot wet and Coastal was designed to have no direct sun on windows, through breezes, and mesh to keep the bugs out.
And initially no AC. It is dilapidated now, but it ac be viewed on address;
20 n North Avenue Appapa, Nigeria’
Ir was designed by Dys, Trocca Valesia in 1592.
Note there is a Wet and Dry season in the tropics, No forms of Ice and Snow.
For passive designs, which are usually very airtight – materials, management of drainage, and moisture / ventilation must be paid careful attention. There’s a good collection of articles here:
Building Science articles on passive design and mold
Insulated rammed earth and many other of the old techniques mentioned above such as adobe and mud walls feature large moisture pervious masses that act as “hygric buffers” preventing mold and contributing to overall comfort.
There is this discipline called bioclimatic architecture which has been gaining traction over time and deals with this kind of stuff though, to tell the truth, there would be so much to be done in both existing and newly built houses that resources would be overstretched to deal with this issue. Of course, we should do as much as we can, but I believe that the building codes are still reactive in this sense, not promoting steep changes until there is overwhelming evidence that something works, and yet implementation of these is being hampered by financial bottlenecks as well as others. For instance, vested interests.
Sorry for the awful phrasing here.
In moderate heat with no a/c people in my area tend to spend their days on a porch or deck. They just don’t go inside until evening because the house is always warmer than a shaded area outside.
At night if the heat is still high sleeping on tile floor (maybe the kitchen in a western home) or a cooling mattress (I used one made of bamboo and it worked well enough) is pretty common in China and other eastern countries, but rarely seen in the West. So adjusting what you sleep on can help.
In parts of Greece, I and other campers tended to sleep on the flat roofs of a night as it was much cooler than being inside the building itslef.
Old California houses from the early part of the 20th century had sleeping porches.
A friend living in northern France said they live in the northern part of the house in the summer and in the southern part in the winter.
Where I live we have cold winters, so the trick is to have a roof overhang just right so that it shades when sun is high (summer) and lets the warmth in when sun is low (winter).
I’ve also read about double roofs on the southern side in the hot climates, so that when the top roof heats up, the ait between the roofs begins to rise, causing draft that draws cooler air from the shady side or under teh building, so the building itself stays relatively cool…
There was a book some decades ago by Ian McHarg about eco community design.
Design with Nature.
I believe u.s. building codes are proactive to block many innovations, and reactionary … designed to serve and protect vested interests in the building trades and building supply industries.
I believe housing in the u.s. is in a very sorry even woesome state … and I see no clear path to a solution. Zoning ordinances and community designs continue to echo Le Corbusier’s “radiant city” at a time when cars and gasoline, and the diesel required to support the logistics of that radiant city” design all promise ever growing costs and inefficiencies. Most of our existing cities await rising tides as the diesel needed to bring goods and services to and from those cities grows more dear. Existing homes and buildings were built for a different climate than that which will come. Many are built too near waterways that will randomly flood their banks as the weather grows in intensity and in chaos. Few are built to withstand the rigors of future and present hurricanes, tornadoes, tropical storms, and hail.
Most existing housing is built assuming the ready availability of affordable electric power delivered through a reliable electric Grid. Most existing housing assumes electric appliances that run on 120 volts of ever available alternating current to provide heating, cooling, lighting, and power for all the electric conveniences of modern life. The u.s. Grid does not appear to me to be especially reliable or well-maintained. Worse I do not see portends of a successful ‘Green’ revolution and more importantly portends of physical repair of the Grid or repair of the horrific economic pattern of private utility companies controlling the flow of electricity from the Grid much as 19th century railroad companies controlled the flow of grain from the Midwest.
I have said little about the insane inflation of housing costs supported by the legal and economic policies of the u.s. government. There are no nice words to describe my thoughts and feelings thereupon.
I believe there is a great deal of technology we must learn from the past, as well as a great deal of new technology and knowledge, and little known or as yet unknown, knowledge of ancient and not so ancient societies that lies far outside the constrictions of u.s. community and housing design. I also believe the many vested interests in the u.s. will continue to twist and warp u.s. housing. I see little or nothing to lend hope that these vested interests can be wrested from their parasitic grip on u.s. housing, short of radical, perhaps revolutionary changes to the u.s. political-economic system.
I hope things may be better in other parts of the world.
I live in a small Portuguese castle town, that was first developed in the 13th century. The current houses in the older part of the town are quite old, including the one that I live in. The town is located in an upper desert terrain, and interestingly, the architecture is very much like that which is described above as “Sumerian buildings”. Small windows, little direct sun to the front face of the house, very thick walls separating adjacent houses, and narrow streets.
The daytime temperatures in the summer tend to be in the ~30-38° range (~85-100° F), with no clouds, let alone rain. The reason that I was willing to choose to live in a place with such heat in the summers, especially given the climate change trajectory, is that it invariably cools down considerably at night ~20-25° range (~68-77° F), and the dew point is almost always very low.
The old construction of the building works remarkably well to moderate the heat in the summer, and also to help to maintain heat generated from a wood burning stove during the winter.
My partner and I occasionally use fans on the first two floors, but have only one air conditioner, which is attached to the top floor bedroom. I’d say that we use that only occasionally during the days in the summer, but with rare exceptions, only for short periods. We almost never feel the need to use it at night, due to the open windows, excellent ventilation, and comfortable outdoor temperatures.
It may seem counter-intuitive to choose, these days, to live in a place that gets very hot in the summers. But in fact, the experiences, and resulting wisdom of the people who have developed the old town over centuries, has left it in better shape to adapt to even warmer temperatures than most, more “modern” towns.
Thanks for making this point, Tinky. Back when we were young, my spouse and I built an adobe in New Mexico’s Sangre de Cristos. Daytime highs varied from nighttime lows by 30 to 40 degrees Fahrenheit in the summer. What moderated our interior temperatures were those massive adobe walls. Adobe is a terrible insulator just as stone is. It doesn’t keep heat or cold out nearly as well as an insulated 2 X 6 stick-built wall. But adobe provides a lot of mass to even out the highs and lows typical of low-humidity climates, especially at high altitudes. We even had an adobe wall running down the middle of the house that really provided some interior mass. To improve the insulation value of the walls, we added 2″ of polystyrene to the outside of the adobe wall that was then stuccoed over.
One thing left out of this discussion that’s been used for some time is using plants to block summer sunshine. We have hops growing up the west side of our house that shades our west windows that would otherwise turn our two west-facing rooms into saunas.
One thing bad about massive walls: once they get cold in winter, it’s almost impossible to heat them up. We lived through a winter in an old inn located in Istria. We only had wood heat, and even though Istria’s Mediterranean climate is pretty mild, once a succession of days in the low 40s or high 30s, cooled those stone walls down, we were cold the rest of the winter.
The Eastgate center in Zimbabwe also seems worth a mention. The idea is said to be based on termite mounds, though it seems not unlike the wind catcher mentione above, just without the wind catching. In both cases air cooled from underground pipes is pulled into the building, hot air is pushed out, and materials with a lot of thermal mass store heat or cool to keep temperature fluctuations throughout the day minimal and allow the building to make use of hot days and cool nights.
https://en.m.wikipedia.org/wiki/Eastgate_Centre,_Harare
Beaverton Oregon is not where hot summers have been expected in the past, but with obvious changes in the last few years we live in a different climate. Tinky’s comments from Portugal (summer highs at 85-100 F), when compared our highs shows western Oregon can actually be comparable. We are now seeing summer highs more like 90-105 F for much of the summer.
Two interesting points I wish to share. One is that our house, built in 1985, has 6″ walls and newer, low E windows with a large front porch facing west. We do have pleated shades and/or Roman blinds on all the windows. Also, the MBR has a quiet ceiling fan which is great for the worst nights when the windows need to remain closed. When built, the porch protected the house from afternoon sun, but now the street trees are so high our front yard is shaded by 3PM. We never need A/C unless temperatures exceed ~95 degrees, except for thunderstorm conditions which keep night temperatures too high.
Second, as neighbors come and go (we have lived here for 22 years) I have noticed that younger people fail to open windows to cool their homes. Maybe I am just becoming a cranky oldster but between not taking advantage of ventilation for cooling and for improved air quality, plus doing no gardening, my interpretation is that “we” are forgetting what we used to know. “We” is obviously a collective or societal observation.
Forgetting what we knew certainly applies to the collective response to a pandemic.
Here’s a project that isn’t concerned with overheating. It’s at 7000′ elevation. It is in remote location so lighting (PV) and heating is the emphasis: http://www.land2plan.com/?page_id=289
These are passive solar design principles. Google it and you’ll see it’s not forgotten. It’s just that most homes are not designed by architects, but “builders”.
I learned much of these principles from inventors like Steve Baer and Steve Wright. The rare Village Homes in Davis, CA is a whole community of passive solar homes oriented toward common community space (and away from the street). It was developed in the 1970’s.
There are plenty of designers with the skills to create adaptive housing.
People in our area are starting to use mini split air conditioners that operate directly off solar panels during the day and only use grid power when too dark or cloudy. With the low price of solar panels, it’s a very cost effective way to go. In a well insulated house, it’s possible to get the house very cool during the day only using the sun then turn off the air-conditioning at night.
This was a good write-up, very short, sweet, and to the point. Five is a nice round number too, but the one general technique that wasn’t mentioned is evaporative cooling.
It doesn’t work in humid climates, but if you have enough water, it can work even when you can’t count on cool nights for a heat-sink. It also doubles as a humidifier for otherwise dry air.
There are several standard Islamic architectural features that rely on it (mashrabiyyas with qullah jars, salsabils), which are probably just refinements of ancient techniques from the Egyptians, Mesopotamians, Persians, etc. With some of the Persian qanats in particular, they would even vent the tunnel into people’s homes for a form of district cooling.
I remember once reading about “windcatching” in the old-to-ancient Iranian city of Yazd.
https://www.atlasobscura.com/places/dolat-abad-windcatcher
Years ago I got a swamp cooler for use here in Silicon Valley because our condo didn’t allow window air conditioners. The purpose was to cool an elderly dog. It worked fine for cooling, but it made the inside of our condo ridiculously humid. I have since learned that you are supposed to use a swamp cooler with windows/doors open; I had kept them shut during the day since that is what you typically do in hot weather here.
(We ended up cooling the dog by buying a stand alone a/c and venting it out a window using cardboard and duct tape to close the gaps.)
Where I am in Hawaii, have neither heat nor AC. We use “trade winds” ventilation, but that requires low density housing. Not going to work in high density 15 minute cities some advocate for.
What’s missing IMO is interior over the door transom windows that open. That allows privacy doors/partitions for bedrooms while retaining ventilation. Lack of through ventilation is a big problem here in condos as fire code doesn’t allow for it. People make unpermitted mods and then the FD gets upset.
I toured some Roman ruins in Tunisia back in 2010. Out in the desert, they simply built underground. For sunlight, they built underground courtyards with large openings to allow sun. These would usually contain a large pool that served as a bath.
All over the torrid in the summer Central Valley of Cali, there are hundreds of circa 1900 cooling towers that aside from growing a bunch of shade trees close to the residence, that was as good as it got.
They are typically 20-25 feet high and taper a bit near the top. They are fairly close to houses, as a tunnel connected to the tower delivers cool air to the residence, hot air goes to the top of the tower.
Pretty cool, eh?
Those sound almost like a “pre-iteration” of the “solar chimney” that Steve Baer of Zomeworks invented at some point in the recent past. The closest a search engine could get me to Steve Baer Solar Chimney was this . . . https://www.builditsolar.com/Projects/Cooling/passive_cooling.htm#Towers
and this . . .
https://video.search.yahoo.com/search/video?fr=sfp&p=steve+baer+solar+chimney#id=2&vid=e29ea311168ccb7edcbad355d9fedd56&action=click
One can also imagine fancy upgrades and tweaks to the solar chimney to make it an even more powerful heat-driven air-sucker.
My son works on cottages for the rich: he installed a 8ft fireplace with 3 insulated vents straight up to the roof. One took the propane burnt gas out (a chimney) the other two took all the heat generated straight up and out, so that no one could get burnt touching the large glass fireplace front. No heat entered the cottage from this charade.
For fireplaces, Count Rumford was the man.
For cooling, I am a fan of incorporating outdoor shaded spaces in the plan.
Utility companies in the united states explored the idea of using vetiver pads in desert coolers, to promote the latter vis-à-vis air conditioners. These types of desert coolers are very popular in India.. Vetiver roots have great coolant properties when water trickles through them… The plant is also great against soil erosion and has a number of other beneficial qualities. However, as I understand it, the whole project got bogged down in bureaucracy and regulations about growing a south asian plant in the United States.