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Part VII: The Part of Tens entire pool changes colors. The lights are fun to swim underneath, and kids love to play games with them. (A word of caution, though: Kids usually wind up breaking them.) The same color-changing scheme is used to good effect in some decorative yard lights. They add just a hint of mystique to your yard and gently catch the eye. If you have a big picture window, put one of these outside it.
Portable Showers Portable showers are kind of silly, I’ll grant that. You fill a big plastic bag with water and set it in the sun. When the water heats up enough (to 105°F or so), you hang the bag from a tree, stand underneath it, open a small plastic valve, and voilà, you have a shower au naturel. Ahhh . . . You can use one near your swimming pool to rinse the chlorine off after a swim. You can use them while camping. You can use one for a hot water bottle big enough to soothe your entire back or stomach.
Sunscreens with Roll-up Mechanisms A lot of sunlight comes into your non-northern windows over the course of a hot day. This has two negative effects. First, the sunlight makes the room temperature hotter, and second, the bright light makes the room seem hotter (a psychological effect). It’s a fact that if two rooms are the same exact temperature, but one has a lot of sunlight and the other is dark, people prefer the darker room. Solar screens reduce the amount of sunlight coming into a room by up to 90 percent. It costs around $2 per year to cover a typical window, and the effect is dramatic. You get the most heat reduction in your house when you install sunscreens on the biggest south-facing windows. You can tack sunscreens up with ordinary thumbtacks, and they look good from both inside and out if you take care to cut the screen corners flush with the window frame. You can make a retractor mechanism for a few dollars. This device allows you to retract the screen when you don’t want it to cover the window. (For the same reason a room seems cooler in the summer with a screen, the room will seem warmer in the winter without the screen.)