Did you know that you can effectively help heat your house in the winter, and cool it in the summer by properly landscaping your property? It is very common to drive through the suburbs and see a few short, new trees that won’t do much as of yet, but when you go through a mature neighborhood, that changes. The trees are tall, the beds are tended, and suddenly the car feels cooler, too, in the summer. Read on to find out how you can use landscaping and architecture to save on heating and cooling and help the environment, too.
Passive Cooling for the Upcoming Summer
If you’ve ever lived in a multi-level home with a basement and second floor, then you have felt the temperature difference on the levels. When you go upstairs during midday you’ll notice it is warmer, and in the basement it’ll feel cooler. Right now, it’s spring, and I can feel the difference from my main level of the raised bungalow to the basement level. Half of our house is sunken, so the earth protects it in winter, but also cools it in the summer. I love this feature, but on the other hand bungalows take up more surface area than the more traditional two-story-with-basement houses.
Passive cooling is anything that you can do to cool your home that is not mechanical. I mentioned the earth cooling above, but you can also use trees. Shade has long been known to be cooler than direct sunlight, so mature trees will help your home stay cool.
Another way, if you are interested in a new build, or gutting your current residence, is to build the home for cross-ventilation. A little research can tell you which direction the wind blows the majority of the time in your neighborhood, and you can open windows. When we lived in a townhome a few years ago, we had optimal cross-ventilation. The unit was not air conditioned, and we were able to live comfortably on the main level with only windows. We had the windows open at night to let in the cool air, and closed with solar curtains during the day to keep out the heat; this is called night flush cooling.
That brings me to the next option for passive cooling: thermal insulation. Insulation has improved immensely over the past 100 years. No longer are we stuffing the cracks with newspaper; we have developed spray foam techniques, fiberglass options, and more. The higher your insulation is rated, the cooler your home in the summer, and the warmer in the winter.
For insulation, don’t forget the windows. Many have insulation built in now to be energy efficient, but there are traditional methods as well. One of the most beautiful options is a window or door quilt. Insulated to keep you warm on the bed, they do an excellent job of keeping the draft and hot spots out of your home from the window glass as well.
Stack ventilation is part of design, and can be added to your existing structure relatively easily. Stack ventilation relies on the theory that heat rises. With the heat rising, it can be sent out through openings in the ceiling, forcing cooler air in through openings at floor height.
A fascinating technique I’d never heard of is a form of direct radiant cooling. In 1977, Harold Hay discovered a way to effectively store the cool air from night in roof ponds, and then during the day he’d cover them so that the cool water could keep the home cool, but also absorb the heat from the day. At night, you open the insulated panels again and the water cools to repeat the cycle. For summer, you would let them be open during the day to store the sun’s heat, and close at night to keep the house warm. I’m not sure if this would still work in a more northern climate without actually freezing the water, but it would be an interesting experiment!
If you’re having trouble keeping cool after all of those options, then evaporative cooling is a minimal electric option for you. If you place a wet towel, for example, over or in front of a fan, then the evaporation of the water will provide cooling of up to 49°F compared to the outdoor temperature.
One more note on earth cooling before I move to heating. Direct coupling was mentioned above in relation to my cool basement being sunken, and maintaining more heat in the winter as well. Indirect coupling can be achieved by having your air ducts buried beneath the surface to cool the air, or in winter, warm the air. This is also sometimes called Geothermal heating and cooling. This is an investment I fully plan on making for my home.
Summer’s Over and Now It’s Time to Heat!
Passive heating can be achieved by employing the methods above, just with a little tweak. Passive heating is the method by which you heat your house without using gas, fire, or another method. Geothermal heating is the direct coupling way of heating your home. It uses long ducts run through the earth in either a large surface or a deep well. This method requires mechanical fans to pump the air through the ducts and through the house, but it does not require combustion. These fans can be run on solar energy if you choose.
Probably the easiest way to use passive heating is to pay attention as to where the windows are located on your home. South-facing windows will let in a lot of sun, and therefore heat, in the winter. Of course, you’ll want to have a good method of shading those windows in the summer so you’re not boiling or spending all that money you saved in the winter on air-conditioning in the summer months!
Solar has been seeing huge gains in the media, and also in real-life application. I have been watching happily as more and more of my neighbors have put up panels. The concept is quite simple and can be compared to a rechargeable battery. The panels capture the sun’s energy, and then the battery powers your home. In some areas, you get a discount on your bill that usually reduces your bill to nothing, and in the summer can even result in a credit for cloudy winter days. There is the option to have your own power be primarily from the solar panels before the power grid, but this is less common.
Trees are a great method of heating your home, as well. When placed along the south side of your house, they can provide cooling during the summer. Windows on the western wall will make your home hotter, too, so look for houses that have as few as possible windows on this side, or if you can’t fix it, use the window quilts mentioned above. Awnings are a great way to provide shade when you don’t have space to plant, too, keeping the wind off of your windows to keep the heat in the house. There’s a lot of great information on this on this website including illustrations.
Solar heating of your water is another way to save money. Traditionally, the home is fitted with a large barrel that must be kept at the temperature you have set on the heater’s thermostat. With a passive solar heater the unit is flat and thin with coils throughout that you can paint black to attract the sun’s warming rays. You’ll get warm water without the gas, but when you run out, it’s out for a long time. 
Knowing which way the wind blows in your area, what vegetation will provide the best shelter, and more will be of great help. Being aware of your climate zone is a part of this, such as planting evergreens rather than deciduous trees to protect your house on the south.
As you can see, there are many ways you can both heat and cool your house to help you decrease your carbon footprint as well as your energy bills. A little landscaping, curtains, and properly placed windows can go a long way! Research what will work in your climate zone, which ways the winds blow, and you’ll be off to a great start!