Image credit Strassburger Windows
It is one of the lunacies of housing in America that builders pay no attention to orientation or window placement, then have to oversize the air conditioning unit to compensate, forcing the homeowner to pay more up front and higher operating costs through the life of the house. So what do you do if you are stuck in one of these dinosaurs? Tristan Roberts of BuildingGreen has some suggestions, which have been republished in Green Building Advisor. Some of them surprised me.
Image credit Kenneth Clark, from A comparative study of a group of early American Windows, 1930
Many of the ideas he proposes are not new, and are seen in the Jessup House in Westport, Connecticut: Curtains, which Tristan claims can block 20% to 60% of solar gain. This surprised me, because it breaks Rule Number 1: Don't let the heat through the window in the first place.
Image credit Kenneth Clark
For those like me who cannot stand curtains, rolling blinds can do almost as good a job.
The Jessup house also has operating shutters, Tristan writes about their virtues:
Shutters shade the window while allowing ventilation as well as daylight; some hinged shutters can be manipulated with adjustable louvers. Hinged shutters generally block views from the interior, though, and are more popular for weather protection. They may also be more accepted in historic areas and condominium communities, where many new-fangled exterior attachments are not allowed.
There are also more modern rolling shutters that are very popular in Europe.
Image Credit Aymar Embury II, from The Livable House: Its Plan and Design MCMXVII
Awnings can block up to 90% of solar heat gain. Tristan notes that they can also save your furniture and upholstery from ultraviolet damage. They used to be common on almost every house, with a service industry devoted to putting them on in the spring and removing them in the fall, so that the people in the home could take advantage of the solar gain in winter.
One very effective solution that Tristan missed is the purgola. Katrin Klingenberg added one to the first Passivhaus in the US because it was too hot in summer with her huge south facing window. They used to be nicely integrated in to the designs of homes.
But the best thing of all is to plan these things out before you build and get it right. Look at this house in Pennsylvania; you can see the shadow line on the second floor, where the roof overhang is deep enough to shade over 2/3 of the window. On the ground floor there is both an overhang and a purgola. Oh, and they have planted some deciduous trees, perhaps the best air conditioning device you can possibly add to your house.
Air conditioning not only makes architects lazy, it makes them stupid. Nobody even thinks of doing these things any more, yet they can make a huge difference in the energy consumption of our houses.
More at Green Building Advisor and Building Green
More lessons from old buildings:
Going Medieval: More Green Design Tips From Old Buildings
Building the Green Modern Home: Looking at Windows
Heritage Is Green: Lessons From The Architectural Conservancy