Interesting DIY sun tracker
 

The creator has it hooked up to a mirror to reflect light into the house, worth a look though I doubt it's very useful: Mustang 4.0 V6

I love the one at the bottom that sticks out of the sidewalk. It's cool to have natural light going into an underground area.

I saw an insulated window cover with a mirror on it: It was insulated with styrofoam and hinged at the bottom. When closed, it fit over the window, keeping heat in. When open, it hinged out, resting on legs attatched to the top, slightly sloping away from the window. The mirror would reflect light and heat which normally would go below the window.

That just gave me an idea. Not a very practical one, but something that could be done in the winter...and possibly summer. Not sure how much heat it would save.

What if you cut out rigid foam to fit into your windows and what not so that, say, in the winter, at night when the sun goes down, you would fit those into your window then close the blinds. And in the summer, if you wanted to shade certain rooms, you could just fit it into the window in the summer during the day.

Wonder how much energy that would save? Or would that be considered a fire hazzard in case you had a fire in your house and it would be blocking your exit...although it would just be a fitted foam piece...not something that would lock in.

Before the new, more efficient (and expensive), argon filled windows showed up here in the mid-90's, most windows were double pane or double windows (like two windows in one window hole: one closer to the outside, one closer to the inside). The double windows opened independently (of course you had to open the inner window to work the outer one), the double pane opened as a single unit, but this unit could be opened to allow cleaning between panes. Some people would put styrofoam (or even straw, earlier) on certain less needed windows for extra isolation. Taping up the whole window opening to keep out drafts was also common.

Today I sometimes see windows in apartment highrises covered in kitchen grade aluminum foil to keep the sun out (11th floor = no shade + heat rising from the lower floors).

An expensive option is an external rolled curtain. It is made of horizontal aluminum ribs, rolled at the top when raised. At first they were used on windows as protection from break-ins, but soon the ribs were filled with a few mm of polyurethane for thermal insulation. This keeps the heat in during winter (but doesn't allow sunlight through), while in the summer keeps the sun and heat out. They can be just slightly raised to allow a draft. Saving to get some installed...

Um, looks like this thread got hijacked. Sorry :/

Ya, I think the hijacking was my fault. But since it hasn't been discussed in such a long time it was time to take it over. :)