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Part III: Doing It Yourself: Small- and Medium-Sized Projects all. A small PV module charges a battery during the day. At night, illumination comes from low-power LEDs. But they show up loud and clear when they’re aimed right. If you want to put up only a string or two, the job takes about 10 minutes. Solar works very well in freezing, clear weather, and the LED lights look great against snow. You may not get a lot of Christmas cheer in extended periods of thick weather. The lights do always go on after dusk for at least some time, but if they didn’t get much charge, they go off soon. Still, do you really need lights after midnight?
Coverings and Barriers: Letting (Or Not Letting) the Sun Shine In Controlling the amount of sunlight that enters your house or patio is an easy way to both regulate temperature and enhance the appearance of your house.
Choosing locations for window coverings Window coverings are a great way to control the amount of light that comes in and to create an insulating or cooling effect in your home. Figure 9-1 shows your different window covering options, and Table 9-1 explains what happens with each one. With a blind inside, you can get the best insulation. However, the heat is inside because sunshine comes in through the window and strikes the blind. The gap between the blind and the window can get very hot because of the greenhouse effect. This result is desirable in the winter but not the summer, when you may have a cooler room if you just leave the window uncovered and let the sun and air in. You can get interior blinds made to warm a room in the winter if that’s your main goal. They absorb sunlight, and they also provide insulation where you need it. On the other hand, interior blinds for summer reflect a lot of light on the outside (exterior) surface, which may be made of a different material or made a different color, from the inside surface. In general, a white blind works well for reflecting sunlight the best, but you can also find (more expensive) specially coated blinds that reflect the maximum amount of sunlight. With a solar screen tacked up on the outside of a window, most of the sunlight is gone before it even gets to the window. The screen gets hot, and you end up with an insulation barrier to keep that heat trapped, but it’s all outside the