We just survived another major heat wave here. People and plants were positively melting. The sidewalks were veritable solar cookers. I’m sure I could have fried an egg on the sidewalk outside my house.
I prefer not to crank the air conditioning, so I have been thinking a lot lately about simple ways to cool ourselves and the spaces we inhabit.
Air conditioning is the main mechanical means by which we cool buildings these days. However, there are several ways that we can cool buildings without plugging in so much as a fan. These technologies are referred to as passive. They don’t require any kind of motor or electricity, just a some good planning and design.
If one were designing a building from the ground up there are myriad features that can help that building use a minimum of mechanical heating or cooling mechanisms. There is no one size fits all design. Passively heated and cooled buildings are adapted to local climate conditions. Current construction practices tend to favor the same type of ramshackle 2×4 and drywall buildings from California to Long Island, and all the climate zones in between. Just stick an air conditioner on top, put in a heating unit, and you’re done. Sadly, most buildings are an energy efficiency disaster. Poor design is so prevalent, it is shocking once you know what to look for. Have you ever leaned up against a stucco or brick wall on a hot day? Ouch! You can literally burn your skin off.
However, a passive building in the humid South, might feature carefully placed windows to maximize air flow. In the desert Southwest, where temperatures can be scorching in the summer and freezing in the winter, thick, heavy walls of adobe, strawbales or rammed earth provide protection from extreme weather conditions.
Here in the Homegrown neighborhood, most of us live in old houses that are not designed with passive solar features. The Homegrown Evolution house is practically a greenhouse. My house is about 20 degrees hotter at night than it is outside. All of the hot air gets trapped and has no where to go. The windows are poorly placed allowing for little cross ventilation. Hot air rises so we need windows up high. Do you hear me architects?
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Yet there are simple things those of us with old houses can do. I already mentioned window placement. Vents up high could also work. Insulation is of course a must. I had my attic insulated a few years ago and now I don’t need to run the heater nearly as much in the winter. I’m not sure what effect it has on the summer heat, because it still feels pretty darn sweltering in here.
Shade is an easy way to keep things cool. Shade can be utilized inside and out. An outdoor seating area begs for shade. This can be achieved with trees and shrubs or vines trained over a trellis. A roof structure of some sort can also provide shade for outdoor areas. If you have pets that spend time outside, make sure to provide them with a cool, shady spot for hot summer days.
Trees can also provide valuable shade for your house. Leafy trees will protect your house from the direct rays of the sun. Shade prevents solar heat gain. Pure and simple. Deciduous trees that lose their leaves in the Winter can allow sunlight to enter your house in the cool season, making them ideally suited to passive heating and cooling.
You can also shade your windows. Solar shades project out over a window, thus blocking the highest angle of the sun. When the angle of the sun is lower and the heat and sun less extreme, in Winter and during sunset and sunrise in summer, sunlight can still get in the windows. A roof that projects past the walls of the house serves the same purpose by also blocking the highest angles of the sun.
I chose to employ this technology and give myself more growing space by building an arbor on the back of my house.
This shades the back of my house and makes it look much nicer at the same time. I have planted hardy kiwi on it. The kiwi will help to provide shade, give me tasty fruit, and because it is deciduous, it will die back in the Winter to allow in a little more light. Brilliant.
This of course is just a few of the things you can do to use less energy to heat and cool your home. But I hope it provides a little inspiration and gets some of you out there to reach for a shovel instead of a thermostat.