You can achieve better insulative properties with your windows by simply covering them with appropriate materials (sun reflectors, insulation webs, and colored fabrics), and making it a habit to open and close blinds and curtains at certain times of the day, depending on the weather and time of year.
Blinds can be great insulators. The honeycomb variety work well in both hot and cold weather. Close them at night or when you’re not home. They can also be excellent absorbers or reflectors of sunlight, depending on what type you get. In cold climates, you want blinds to absorb sunlight and warm up the room. You can do the same if you open the blinds, but then you won’t be insulating. There are a wide range of blind styles, and it’s impossible to get into details here. Big box hardware stores all carry a number of brands and have very good samples you can get your hands on. Prices vary from $20 per window to more than $300 per window.
On the other hand, if your main problem is heat in the summer, you want a blind that will reflect sunlight as much as possible. If you simply put a blind inside a window to keep sunlight out of the room, it’ll absorb a lot of heat, but the heat will still be inside the room. You can put blinds over windows on the outside, which works much better in hot weather because the sunlight is stopped outside. Of course the blind gets really hot, but who cares? Go to your big-box hardware store to see the various options. The best bet, from my experience, is the solar screen variety because you can see through the material (sunlight is attenuated 80 percent or more, so the view is darker), but you can still see the view outside. (See Chapter 9 for more on blinds.)
If you have a big picture window that lets a lot of sunlight in on hot days, you can hang a cheap, roll-up blind on the outside. Get one that’s solid so that it completely cuts off all light. If you can, leave an air gap of 6 inches or more between the window and the blind. Yes, the room will be dark and creepy, but if you’re at work for the day, it won’t matter, and the room will feel a lot better when you get home. Buy a cheap one because it probably won’t last more than a season or two hanging outside in the direct sunlight. Take it down and store it when autumn arrives.