Beat the Heat: How Design Can Keep You Cool

Exterior of a two-story house with brown siding

Mr. Exuberance / Wikimedia Commons / CC BY-SA 3.0 

Over on Curbed, Robert Khedarian describes how houses were cooled before air conditioning, a theme we have covered on TreeHugger many times. He leads off with a photo of Greene and Greene's Gamble House in Pasadena, noting that it has a big sleeping porch. But he misses the big lessons from that house: the massively deep roof overhangs that shade the house in summer. Note also that the windows are surprisingly small for such a large house, to minimize heat gain.

Exterior view of a brick front house with several roof overhangs
Lloyd Alter / CC BY 2.0

It worked in Pasedena and not so well in Buffalo, where Frank Lloyd Wright designed the Darwin Martin House; Mrs. Martin found it cold and dark. But deep overhangs on south-facing facades, calculated to let the sun in during winter and shade it in summer when the sun is high, were a basic design principle.

Cross-Ventilate Everything

Bremer plan

Aymar Embury II / Public Domain

Another feature in the Gamble House and almost every house designed before air conditioning, in the north or south, is that bedrooms, wherever possible, are in corners so that they have cross-ventilation. This is something that could and should still be done in houses but rarely is.

Get a Shotgun House

Long white "shotgun" house with a black porch swing
Bubba73 / Wikimedia Commons / CC BY-SA 3.0

Then there is the shotgun house; Curbed doesn't mention that the one they show is actually Elvis Presley's birthplace. According to Michael Janzen of Tiny House Design, they got their nickname "from the idea that if you stood at the front door and fired a shotgun the buck would fly out the back door without hitting the house." The small, affordable houses had rooms behind rooms with no hall, in the french enfilade style. The benefit is that without a hall, every room has cross-ventilation. Not much privacy though.

Add a Cooling Cupola

Cream-colored house with a cupola, with a grassy lawn and trees
Harvey Harrison / Wikimedia Commons / CC BY-SA 3.0

Another old trick is to add a cupola, like on Edenton, North Carolina's famous 1758 Cupola House. Since heat rises, you get a stack effect where air is sucked in through the ground floor windows and continuously flows upward. It also provides natural light to the interior.

Tricks Learned From Southern Homes

White house with red roof over porch, with palm trees in front
EdisonFord / Wikimedia Commons / CC BY-SA 3.0

In fact, there was a big toolbox of ideas for keeping cool in hot climates. Thomas Edison's house in Fort Myers had alot of them. The Florida vernacular, now totally lost, was described by Dorinda Blackey:

Florida's indigenous builders developed several architectural elements to combat the intense summer heat and lack of breezes, The use of extensive porches and large roof overhangs provided extra protection for shelter from the sun. Porches were also important living spaces allowing the user to enjoy what little breeze there might be available for cooling. To maximize these breezes on the interior space large window openings and cross ventilation designs were utilized wherever possible. A steeply pitched roof with high ceilings induced extra ventilation on the interior spaces, too. During these hot seasons the extensive rainfall acts as a natural cooling factor. The large overhangs and porches allowed windows to remain open during the rainstorm allowing the interior to take advantages of their cooling effect.

Tricks Learned From Northern Homes

beale house

Aymar Embury II / Public Domain

Further north, there were all kinds of tricks that could be combined; in this one photo you see purgolas and overhangs, large casements to catch the breeze, and deciduous trees that shade in summer but drop their leaves in winter. Standard practice among architects with any sense.

Celebrate Thermal Mass

Stone facade of Roman ruins
Larry Speck

In the southwest, where it is dry and there is a" high diurnal swing", where it is really hot in the daytime and cool at night, one can put thermal mass to work. It turns your home into a thermal battery, keeping it warmer at night and cooler in the daytime. Architect Larry Speck describes it:

I became interested using high thermal mass as an alternative while traveling in Turkey with my son Sloan eight years ago. He and I visited remote Roman ruins on the south coast and the interior, where the sites are in raw states and are not much frequented by tourists. The summer climate in Turkey is very hot and humid, not unlike Texas. But it was strikingly comfortable inside the stone ruins with their high thermal mass.

Install External Blinds

External blinds on apartment buildings along a street
Lloyd Alter / CC BY 2.0

In Europe, many people hate air conditioning; the French insist it makes you sick. But many live in buildings with thick walls, relatively small windows and external blinds that they leave up at night when it is cooler, and pull down in the daytime to keep out the sun and trap in the cool air. But it also works in newer buildings or where people have added AC; as one manufacturer of European blinds explained:

External blinds "are the most practical method of controlling solar heat gain. The problem of solar heat build-up is combated before it becomes a problem by mounting the blinds externally, where they intercept and defuse the suns rays. When Exterior Blinds are used in conjunction with air-conditioning, the air-conditioning units can be smaller, cost significantly less, and operate more economically because of the reduced demand on the air-condition system."

Keep Cool With Culture, Not Contraptions

Perhaps the most important lesson from the way people did things in the past is this; that we should adapt the way we live to the climate, instead of throwing money at air conditioning and hiding inside. Barbara Flanagan once explained how they do this in Barcelona:

The secret to Catalan comfort is not a gadget, but a self-induced, mind-body state of discomfort suspension: heat tolerance. Accordingly they plan their seasonal vacations, daily routines, food, drinks and wardrobes for maximum cooling. In other words, it is the culture that cools, not the contraptions.

Do These Techniques Still Work?

Black and white photo of a tenement roof
National Archives and Records Administration / Wikimedia Commons / Public Domain

Alas, most of these tricks only work on detached houses on big lots, unless you are willing to live in a shotgun. And we live in a hotter world. More and more of us are living in cities. For years, I have been showing this photo of an old tenement roof, suggesting that this air shaft created a stack effect that ventilated the apartments below; in fact, they were horrible:

..they had these tiny light slots or light shafts in the middle that were so narrow that you could actually reach out and shake your neighbor's hand. They received almost no light, unless you lived on the top floor. If it was a hot day and people opened their windows, you might have 20 or 22 families living with their windows open in this tiny little shaft, so [imagine] the noise and the smells of all of these apartments.

That's why people would sleep in parks. And that is why air conditioning has been such a blessing; because none of these techniques worked all that well. They help, but the more important design approach today is to do everything possible to reduce the amount of air conditioning needed. That might mean a lot more insulation and smaller, but better windows. Or as I put it in an article on the subject:

We need a balance between the old and the new, an understanding of how people lived before the thermostat age along with a real understanding of building science today. To discover what we have to do to minimize our heating and air conditioning loads and maximize comfort, we have to design our homes right in the first place