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CHAPTER 7

Design Considerations

After playing the Design Game, you’ll have come to certain conclusions about the house you want. Before you move on to a scaled drawing or design, there are some technical aspects to be addressed. It’s time for you to become aware of some key design considerations.

The results from your Design Game are an important beginning. You will have gained some clear understanding about your future home and learned about the kinds of decisions and compromises that must be made along the way. Depending on your level of experience and the range of your personal concerns, you may or may not have addressed certain technical issues in your version of the Design Game.These elements must be addressed before the Game is over and the working design is created.

Some New Pieces for the Design Game

Passive Solar Design

Early cave dwellers knew about it,wild and domestic animals know about it, and some cultures still practice it, but passive solar design has been neglected in modern home design. Incorporating passive solar elements into your house is easy to do, and the rewards are significant. Given the importance of the sun in all aspects of how we function in our built environments,it is really quite remarkable that paying attention to the sun’s interaction with our buildings isn’t part of mainstream building practice. It seems odd that such an important topic is rarely addressed, and when it is addressed, it’s as though it’s a specialty concern. It should be fundamental: if you’re undertaking a building project, please don’t ignore the sun!

Ever watched a cat or dog stretch out on the floor in a pool of warm sunlight? Passive solar design can maximize your home’s exposure to those warm rays and give them a chance to heat your home in the colder months. At the same time, proper passive solar design ensures those same rays are kept out when you are trying to keep your home cool in the summer. By simply taking account of the sun’s position in the sky, you can lower the cost of winter heating and summer cooling dramatically, while improving occupant comfort.

Passive solar design is premised on the changing position of the sun from morning to night (east to west), and from winter equinox to summer equinox (low on the horizon to high). At each time of day and in each season, we want our buildings to coordinate their performance with the sun’s position.

7.1: This is a good example of effective passive solar design. South-facing windows on both floors are shaded in summer and open to the sun in the winter. The “eyebrow roof” is slanted at a good angle for mounting solar panels.

There is no one-size-fits-all strategy for appropriate passive solar design. Much will depend on your geographical location (your latitude), your climate, the specifics of your building site, and your daylighting needs inside the building.There are three basic elements to consider in passive solar design:

• building orientation and shape

• window placement and shading

• occupant needs and movements

Building Orientation and Shape

The classic passive solar strategy calls for a building that is oriented so its longest side faces south (reverse for the southern hemisphere), creating a building along an east-west axis. This allows you to maximize your south-facing windows for passive heat gain in the winter. It is a good strategy, and when the site and occupant needs allow for such a shape, it is simple and effective.

However, a lot of building sites do not allow for this long and skinny approach. But that doesn’t mean you have to give up on passive solar design. There are many building shapes, some simple, some complex, that allow for good use of the sun. Even on sites where southern exposure is limited or the building is constricted by lot size, there are ways to maximize passive solar aspects.

When siting a house to face south, simply locate the sun around noon. That’s the direction you want! A compass will point you in a direction that is not quite true solar south, since magnetic north and true north are not aligned perfectly. If any bias is to be made away from true south, it is best to shift a bit to the east to maximize your morning exposure and minimize late afternoon overheating.