Author Options:

Blocking Sunlight Answered

Would putting aluminum foil on the windows on the side of the house that gets the most sun be helpful in blocking out the heat of the sun?

Our HVAC literally runs all day, from 8am-1am, and we're trying to help cut out some of its work before it goes on strike! If you know what I mean...

Any advice?


We bought some static-cling tint for the windows that get the most sunlight. That way we can pull it down in the winter time so the sunlight can come through. Crossing our fingers!

That's probably better - may not block quite as high a percentage of sunlight, but avoids giving your house that "Cheapskates Live Here" look that aluminum foil tends to create.

You've already changed/cleaned the filters on your HVAC system, haven't you? Right, that's good to hear. :)

Hanging outdoor shades from the eaves on that side of the house can help also, as can shades or curtains inside the house.

Be sure to open the house up at night or in the early morning when things are coolest, to let that cool air in. (If the air doesn't cool much at night, and you're really desperate, try setting an alarm for 5:00 am - get up, open doos and windows, go back to bed.) Try to set things up, assisted by fans as needed, to get good cross ventilation (http://www.sustainable-buildings.org/wiki/index.php/Cross_Ventilation).

Of course, turn off everything electrical when it's not in use. Electronics, including your computer and TV, generate a lot of heat when not  officially "on,"  so shut them down too. Don't use the oven unless you have to, and then try to pre-cook things late at night/early in the morning. (And, even though it's tempting as all get out, don't stand inside the open refrigerator door. :)

There is that plastic sheeting that is shiny silver on one side and duller on the other: so you can reflect sunlight in the summer, and absorb it in the winter :-)

.  It works very well. I have some south-facing and west-facing windows that I covered the bottom 2/3 of with Al foil - makes a big difference. Works even better if the foil is placed outside the window (reflect the heat before it can enter the house).
.  The north side of my house faces the street, so it doesn't look too tacky. ;)

It won't hurt, since you're willing to block the light, you'd be better getting some foil backed foam board from the hardware store and cutting plugs to fit the windows. Something I did for half my sliding glass door. BTW when was the last annual maintenance on your AC?

Using room darkening shades or curtains and having them cover the windows during the sunlight hours would help in preventing the "greenhouse" effect from heating up the room. You could tint your windows too.