Building envelope: Windows

Windows are one of the most important parts of the building envelope. Despite the effectiveness of modern artificial lighting, a room that has no windows feels dead and uncomfortable. Windows bring a room to life by bringing in natural light and connecting people to the world outside.

Natural Light

Wings of Light (107):

• Problem: Modern buildings are often shaped with no concern for natural light — they depend almost entirely on artificial light. But buildings which displace natural light as the major source of illumination are not fit places to spend the day.
• Therefore: Arrange each building so that it breaks down into wings which correspond, approximately, to the most important natural social groups within the building. Make each wing long and as narrow as you can — never more than 25 feet wide.
• Our house is not long and narrow — in fact, its main body is a square. Each side of the square is 32′ long. Thus, we are violating the letter of the law. But how do we rank against the spirit?The reason for the 25′ width restriction is that in an average room, significant amounts of light only penetrate about 12′ from the window. A 25′ wing with windows on both sides will just barely get enough light.

  Fortunately, our home uses several techniques to allow above average light penetration. Our ceiling is 10′ high, and the main windows in the living room go all the way to the ceiling. Walls are mostly white. These factors together allow more light to go in further and reflect effectively. As the picture below shows, this results in a living space that can be illuminated primarily by natural light.

Natural light on the main floor

Indoor sunlight (128):

• Problem: If the right rooms are facing south, a house is bright and sunny and cheerful; if the wrong rooms are facing south, the house is dark and gloomy.
• Therefore: Place the most important rooms along the south edge of the building, and spread the building out along the east-west axis. Fine tune the arrangement so that the proper rooms are exposed to the south-east and the south-west sun. For example: give the common area a full southern exposure, bedrooms south-east, porch south-west. For most climates, this means the shape of the building is elongated east-west.
• In our home: We have a great southern exposure. We took advantage of this by making sure the southern wall of our main floor has a lot of windows. Because we have an open floor plan, we are able to get large amounts of natural light even with a fairly square building layout. The picture above looks from our living room toward the kitchen. The window nearest the back corner of the kitchen is about 27′ feet away, but it is still well illuminated — and we haven’t even taken the protective films off of the windows yet.

Light on two sides of every room (159):

• • Problem: When people have a choice, people will always gravitate to those rooms which have light on two sides, and leave the rooms which are lit only from one side unused and empty.

• • Therefore: Locate each room so that it has outdoor space outside it on at least two sides, and then place windows in these outdoor walls so that natural light falls into every room from more than one direction.
  • In our home: Having windows on multiple sides evens out the light. If light only comes from one window, there will be a high contrast between the window and its surroundings. Most of our primary rooms have windows on two sides. (See the floor plans below.)However, since our home doesn’t have crinkly edges (they are not energy, material, or labor efficient), we could not achieve this everywhere. For the most part, the impact of this was minimized by putting rooms that aren’t as important in the non-corner positions. Where non-utility rooms have ended up with windows on one side, we are able to mitigate issues by using glass doors to help borrow light from other rooms.

Light on two sides of the living room

Upstairs windows. Yellow arrows highlight windows.

Main floor windows.Yellow arrows highlight windows.

Views

Looking west from the living room deck

Panorama looking west from the living room deck

Panorama looking west from the master bedroom

Zen view (134):

• Problem: The archetypal zen view occurs in a famous Japanese house, which gives this pattern its name. [A Buddhist monk has a beautiful view, but it is only seen in passing as you enter the home.]
• Therefore: If there is a beautiful view, don’t spoil it by building huge windows that gape incessantly at it. Instead, put the windows which look onto the view at places of transition — along paths, in hallways, in entry ways, on stairs, between rooms. If the view window is correctly placed, people will see a glimpse of a distant view as they come up to the window or pass it: but the view is never visible from places where people stay.
• In our home: We mostly failed to achieve any Zen views. Our windows, especially in the living room and bedrooms are large to let in the light, but they make for gaping views. To some degree, this was unavoidable — the views and the light were coming from the same direction.However, we did manage to apply a little of this philosophy in our stairway. We intentionally placed our stairway to the west. This cuts off some of the western view from the main living spaces. Instead of having big gaping windows in the stair tower, we choose to use multiple smaller windows. These break up the view, and because they are smaller the view shifts as you use the stairs. This gives the view a bit of mystery and dynamism that it would have lacked if we’d made the more predictable decision of having the west wall given over to view with the stairs pushed to an interior wall where they wouldn’t effect the view.

Breaking up the view with smaller windows

Windows overlooking life (192):

• Problem: Rooms without a view are prisons for the people who have to stay in them.
• Therefore: In each room, place the windows in such a way that their total area conforms roughly to the appropriate figures for your region…, and place them in positions which give the best possible views out over life: activities in streets, quiet gardens, anything different from the indoor scene.
• In our home: A challenge of our site is that it is fairly heavily slopped. The second picture below is taken from our main floor — ground level on the entry side but, as the picture shows, rather high by the time you get to the other end of the building. Thus, all the life we look out on is rather distant.But almost every window, expect those on the north facing the neighboring house, are fortunate enough to have a view of the nearby trees and, eventually, our gardens.

The main floor is rather far above the ground