Post date: Oct 15, 2014 1:43:13 PM
Windows have always been expensive. Before the advent of glass, windows meant letting in the cold. In times of trouble, windows let in arrows or bullets and intruders. So windows were often small in the past. Our heritage of multi-paned windows reflects the impossibility of making large sheets of glass as recently as a century ago.
With the advent of double-pane insulating glass some of the disadvantages of large windows were alleviated. California ranch-style houses introduced sliding glass doors to millions. Even adobe houses in Taos boast sliding glass doors.
But I’m not sure that all this glass is what I want. My chosen passive solar design very carefully balances solar heat gain, heat storage, and heat loss to achieve a comfortable, stable indoor temperature at low cost.
South-facing windows can either block heat or let it pass. Generally, in the winter, you want that solar heat to warm the house and be stored by the floor slab to be released during the dark night.
North-facing windows will always radiate heat from indoors to the outside. It is possible to coat the glass (“low-E” that do not emit much radiant energy), and this will reduce the radiated heat loss, but not eliminate it.
West-facing windows almost always overheat a house because the outdoor temperature in the afternoon reduces the heat loss from the rest of the house while heat is pouring in from the afternoon sun. Just the opposite, east-facing windows admit the warm rising sun just when the outdoor temperature is coldest.
And all windows (and window frames) are much less insulating than the walls that embed them. (The best have an R-value of 5, in a wall of R-30.) In addition, openable windows (and doors) will eventually leak air, and air leaks are a much more important source of heat loss in buildings than heat losses through walls or glass.
All that mechanical stuff aside, we have the visual aspects. Windows let in light. Light is important to see what you are doing indoors. Light also lifts the spirits - as one from the cloudy Pacific Northwest can attest. Our 1916 house in Seattle has windows in every space, including all the closets, entry hall, stairwell, and basement. In the day there is no need to turn on a light.
Windows also visually connect the inside to the outside. This can be both good and bad. It is helpful to see who is coming to the door. It is nice to look at the mountain on the horizon, or the birds drinking in the fountain. But do I really want to see the patio paving?
Windows require window coverings to provide privacy. Window coverings can also improve the insulating properties by blocking radiant energy from warm people to cold night air. But window coverings, too, can be expensive. For thirty years we had no window coverings on the lower floor of our house in Seattle. And we only had blinds to keep out light in the bedrooms.
The opposite of windows is walls. For me, walls provide a place to hang things I want to look at. This includes rugs, photos, prints, metal sculpture, embroidery, quilts, paintings, and masks. I have asked for picture molding in my new house, but if there are no walls, I can’t hang the pictures in front of the windows. By my inventory, I have 80 linear feet of stuff hanging on the walls. That is half the total exterior walls of my planned house, including bathroom and kitchen.
Yes, we currently have stuff hanging on the walls of our kitchen and all three bathrooms. And, yes, I recently uncovered a stash of 22 posters, prints, and a sand painting that had been in the back of a closet - not included in my inventory.
So, clearly, I like looking at the indoor stuff. I also like looking at birds and flowers outside. I like having plenty of light inside. I like looking at the mountains and seeing who is standing at the door. But I don’t need to see the patio paving. And if I want sweeping views, I can step outside.