The other day we had lunch in Grass Valley in a building that was constructed in the 1860’s. Now, it was a fairly hot day, but the building was cool even with the windows open and no air conditioning. This got me to thinking about what people did to stay cool in hot weather in the past. After all, air conditioning has only been available to most people for the last 50 years or so.
I have spent some time in Arizona and Nevada, and one thing that I have noticed is that many of the newer homes and other buildings are so dependent on air conditioning you would have to break the windows to get outside ventilation. If the power is out, there is no cross ventilation and the buildings would become a hot box.
The trick is to live in a home that is “weather advantaged”. In other words, it was designed and situated on a plot of land for the purpose of staying cool in the warm months and warm in the cold months.
If you are looking to design a home, buy one, or even rent, take a good look at the home and see if you will be able to stay cool in the summers. Here are a few tips for either building a “weather advantaged” home or looking for one if you’re going to buy or rent.
- Take a look at the way in which the home is oriented. More windows should face south than east or west. During the summer months, more sunlight enters a house through east- or west-facing windows than through south- or north-facing windows. The vast majority of the heat and cold that gets into your home comes through the windows. Also, take into consideration in what direction the prevailing breeze comes from.
- The windows should be shaded from the outside. This is why so many homes used to have awnings or large wrap around porches. In the summer, the sun is higher in the sky and you can shade your south facing windows and still have the sun heat them in the winter when it is lower in the sky. When designed correctly, the overhangs will allow full winter sun to enter the house and completely shade the windows from the hot summer sun. The size and design of the overhang will depend on your climate. In general, shading windows on the exterior is better than using interior blinds, as it keeps out more unwanted heat. Shading devices can include trellises, shutters, roof overhangs and shade trees.
- If you are designing a home from scratch, go with high ceilings. In older homes, you will notice that in hot areas they often had 10 or 12 foot or even higher ceilings. High ceiling combined with tall double hung windows provided good ventilation.
- Everyone knows that heat rises, so if you have windows high on the walls and open them when it’s hot inside, the hot air will vent out. Now, if you have high ceilings with double hung windows, here’s what happens. When air passes over your home, it works the same way as it does over an airplane wing. The Bernoulli Effect causes the air on top and on the downwind side of the house to be at a lower pressure than on the upwind side. So if you have double hung windows, you can open the bottom section of the upwind side of the house and the upper section of the downwind side and the low pressure will suck the air through your house. Make the outlet openings larger than the inlet opening. This increases the draft. When I was in the fire department, we were taught to do this to help remove the smoke from a building faster.
- Insulate your home well. Many of the older buildings in the hotter climates were made of adobe or brick with the walls a foot or more in thickness. Often, a foot or two of dirt was placed in the attic for insulation. In the older homes the brick or adobe would cool at night and help keep you cool during the day. Today it is a lot easier to insulate your homes with the new products that are available. Unwanted heat gain enters a house not only through windows, but also through the walls and roof of a house. Don’t forget to use double pane windows.
- Provide a reflective roof. A light-colored, reflective roof may help to keep your home cool by reflecting the hot sun. The best such roof should not only be reflective, but also have high emissivity. Look for roof materials certified by the Cool Roof Rating Council or the Energy Star Roof program.
- You need a home with effective cross ventilation. It amazes me how many homes and other buildings today are not designed to provide cross ventilation. You need windows that will open on all sides of your home to allow for good airflow. Opening the windows at night can cool your home and if you combine that with good insulation, by closing the windows during the day, you can stay cool all day.
- Install transoms. These are mini windows above doors and they’re something that you never see anymore. However, they work to help keep you cool. Operable transoms allow natural light and vent to flow from bedrooms to areas that typically don’t have access to natural light and vent, such as hallways, closets and other rooms without windows. Transoms also provide the benefit of exhausting hot rising air while allowing doors to stay closed for privacy and sound control.
- Planting Trees. By planting shade trees in proximity to your home, particularly on the west side you can shade your home. If you use deciduous trees, they will let the sun in during the winter when you need the heat. Get in touch with a knowledgeable arborist to make sure you’re planting trees that will provide the type of shade you want. You also want to make sure your space will be large enough to accommodate the full-grown tree and that you won’t run into problems with root growth.
- Cook outside when possible. In the past, many people cooked outside during hot weather. They would build permanent stoves outside under covers that were open sided. This allowed for breezes to help keep the cooks cool and keep the cooking heat out of the house. Outdoor kitchens are trendy, so it’s easy to find plans online and in books like this one.
- Roof vents. Make sure that you have good roof vents to take the heat out of your attic.
- Screened-in porches. In the past, many homes had screen porches and if it became too hot, people would sleep in them.
Whether you are looking to buy a new home, building one or looking to improve your current one, take these ideas in consideration. As you implement these tips, you will see that they work. While they may never be quite as good as modern air conditioning, they will help you stay cool.