The Efficiency of Ancient Passive Heating and Cooling Techniques
With rising heat and air costs, and a desire to be as sustainable as possible, I decided it would be wise to take a look at some of the ways that ancient people kept cool in the summer and warm in the winter without the use of HVAC or even electricity. From my research, some of which I have shared below, it is clear that those who came before us knew how to take advantage of the "lay of the land" and were very in tune with their natural surroundings.
From the very beginning man experimented with ways to create a safe and comfortable indoor climate, irrespective of the conditions outside.
The first abode of man, the natural rock caves, offered him protection from the elements albeit in a basic way. The rock walls provided insulation from both the cold and the heat. Dwellings cut into the soft volcanic rock in Cappadocia might have served the same purpose. In France, you can still find the cave dwellers or troglodytes of Graufthal.
A Hole in the Ground
It’s not just the Hobbits of the Shire who built houses into the ground. An underground level to the house helped modulate the indoor temperature to a great extent. Today we see rising popularity of homes built completely or partially underground, where the temperature remains stable all of the time.
Houses on Stilts
Keeping the main floors up and away from the ground keeps them cooler when the summer sun heats the ground, and warmer when the ground is cold. Stilt homes are still in use today in many parts of the world.
Generating heat when it's cold outside is a simple proposition and there are many variations on "build a fire," from an open pit fireplace to a high tech furnace. But when It's hot out and you want to cool your living space, the options aren't as obvious. In the hot regions of the world, traditional architecture incorporated ways and means to keep the indoor temperature several degrees cooler. Their approach was essentially two-pronged.
Protecting the Home From the Sun
Double walls for the exterior of the house
An outer wall with a perforated design called "jaali" ensures insulation from the elements by creating buffer zone between the house and the outside.
A thatch of straw above a mud or wooden roof keeps it cool. In areas with rainfall, a sloping tiled roof protects the flat roof from water damage. The upper roof extends well beyond the outer walls of the house all around, shading the walls and the windows from sun.
Using Air and Water Currents to Cool the Indoor Air
- Central courtyard houses
This open-to-sky area provids extra ventilation, setting into motion an air current through the house. Hot and humid coastal areas benefited from this design.
Step-wells for central air conditioning
A sunken courtyard filled with water keeps the indoor air several degrees cooler in hot and dry inland regions. Mughal palaces used running water channels around the rooms to create comfortable interiors.
These ventilating structures rising above the house let the wind draw up the air inside, creating a constant air current through the house. Sometimes they are connected to a deep well in the ground so that cooler air circulated.
In windless areas, tall chimneys painted black allow the sun to heat up the air. The rising hot air pulls up cooler air from the lower levels of the building, creating a current.
A wet screen hung in the doorway or window against the direction of the wind brings in a cooler breeze. In some Indian homes, the screen was made of a naturally fragrant grass root called Vetiver. In summer, water was sprayed on the screen every morning creating cool and fragrant air inside. This technique is still used today.
Architectural solutions for climatic conditions are not exclusive to eastern architecture. An example is the old adobe houses in the South West, made with mud bricks incorporating straw. The extensive pillared porches around the colonial Southern houses helped shade the windows from harsh sunlight.
If you are like me, thinking of making a move to be sustainable, consider incorporating some of these passive heating and cooling techniques into your new home. You will make a lasting impression on the earth and your pocketbook. This is a win win for sure!