Windcatchers have been employed for thousands of years to cool buildings in hot climates. The windcatcher is able to chill indoor spaces in the middle of the day in a desert to frigid temperatures.

Windcatchers have been employed for thousands of years to cool buildings in hot climates. The windcatcher is able to chill indoor spaces in the middle of the day in a desert to frigid temperatures.

The following list includes dozens of low tech, low cost ways to cool buildings in hot climates passively without electricity or machinery, i.e., passive cooling or natural cooling. This list is in addition to the 11 or so simple passive cooling techniques that I talked about in my video the other day. Altogether there are over 50 practical methods for cooling your home sustainably. Despite all these wonderful methods, most people – at least in North America – live in poorly insulated boxy houses with costly, wasteful air conditioners. This is one example of “ignorance is not bliss”.
– night cooling: open the windows at night to let in cooler, fresher air.
– roof vents for improved ventilation. This could include a ridge vent and cupola.
– gable vents on gable end walls
– adequately shaded clerestory windows
– smaller windows on the east and west to prevent overheating (if the walls aren’t shaded)
– louvers and vents
– well located doors
– 50-100% more or larger windows on the leeward side than the windward side to help hot air to escape
– earth berming with moist vegetation such as grass
– keeping vegetation moist around the house to help cool the breezes (the yard)
– planting trees to funnel air toward your house
– plant trees that don’t block breezes
– wing wall to direct cool breezes into the home
– building on stilts
– stack effect: multi-story designs can be very effective at encouraging natural convection
– open plan living areas that encourage air circulation
– narrow floorplans
– orientation to catch breezes more effectively
– location: breezy locations near lakes, etc.
– outdoor living areas
– porches/verandas that shade the walls
– shaded, high thermal mass walls such as earthbags, adobe, etc.
– windscoop/windcatcher (with possible addition of a water element)
– evaporative cool wall such as double terra-cotta brick walls (low fired brick) filled with moist sand
Venturi effect
– solar chimney: chimney designed to heat air and draw air from the house
– atrium or sunroom: can act like a solar chimney if properly designed
– basement: upper floors draw cool air upwards from the basement
– cool pantry and rootcellar
– well, open air cistern or underground water canal in the basement
– earth tubes in dry climates where mold is not a problem and digging is fairly easy
– roof insulation and reflective roof insulation
– fly roof (secondary roof over the main roof)
– green roof/living roof
– soffit vents and baffles between rafters to improve roof ventilation
– light roof color that reflects sunlight
– manmade water feature such as a lily pond on the windward side
– awnings (if you don’t have large roof overhangs)
– inner courtyard/open atrium
– pergolas and trellises to shade walls
– minimize sun reflection and re-radiation from surrounding environment: plants versus gravel or pavement
– blinds: close if sunlight is entering window
– avoid skylights unless openable and tinted
– smooth plaster reflects more light than textured plaster

Note: This is just a list of practical cooling strategies. There are plenty of ‘yeah, buts’ you should be aware of to prevent problems. There isn’t time or space here to cover everything. A fair amount of research is required to learn the details so you can optimize the passive cooling design for your home and building site.

Image source: Wiki – Windcatchers (good info on windcatchers)
Good reference with more details: Passive Cooling at House-Energy.com


Comments

Additional Passive Cooling Strategies for Hot Climates — 8 Comments

  1. Amazing what African termites can teach us humans – they have been building these efficiently cooled “mounds” in the desert out of dung for millions of years and just now are we figuring it out. I live in Mojave, CA – today’s temp is 107. My A/C will cost me $200 this month. While I cannot dig the underground structure, as I am on a slab foundation. I will just have to put in an evaporative cooler, to reduce the cooling costs. Unless I can hire 19 million termites

  2. I’m amazed at how many simple things can be done to cool houses. That’s a pretty long list! Just one or two things like installing a white roof and adding the right size and number of windows makes a huge difference. So it’s sort of bewildering to see so many poorly built houses that are reliant on air conditioning.

  3. I watched a show about the 2011 tornado season,Joplin,mo sure was bad.I keep thinking about how much sense an earth bermed or under ground house would make.They talked about storm shelters and the picture showed them underground of course.I think the heating and cooling would make more sense also

    • Most cultures evolve over time and utilize things that make sense. I could give you all sorts of examples, but I think everyone knows this. For some reason many/most people in hurricane and tornado areas have not evolved their thinking. Nature has a cruel way of dealing with ignorance.

      • I blame building codes and mandatory insurance issuance policies. Local building authorities are basically revenue streams for the city governments and construction companies, so they have no incentive to require or even allow people in hurricane-prone areas build sensible structures. In addition, in a free world, insurance companies would discover that shoddy houses in disaster-prone areas receive more damage and are more likely to be total losses, and so people who lived in inappropriate housing who wanted or needed insurance would face high premiums or even be uninsurable. But instead, insurance companies are forced to issue insurance to everyone, regardless of the actual underlying risk, thus eliminating another incentive for people to build climate-appropriate houses.

        • It’s crazy, that’s for sure. Things are definitely not set up to favor the average working guy or gal. The good news is inefficient, corrupt systems ultimately fail, and major cracks are starting to appear.

  4. Good information Owen. Some of this information will be useful to me when I build, but here in Sticky Hot summers and somewhat cold winters (West Tennessee) with maybe 2 or 3 snows if that during winter, we will be looking at some slightly different ideas. Maybe a earth berm round house? Design we are leaning to is nothing larger then 1000 square feet. So maybe 2 smaller structures connected with a living space between the two? I like the house in south america cant remember which country but it was 2 domes connected with a somewhat rectangular structure in the middle. Domes wont work in our climate do much drastic weather changes so a traditional roof more then likely metal. Oh decisions decisions.

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