1. Archive

Ways to keep heat out of the house

Published Sep. 13, 2005

(ran HS, HL, HP editions)

Question: We hate to close the drapes in our living room because the view is so nice, but the sun just pours in and makes the room so hot that we can never get comfortable. Would window tinting solve our problem?

Answer: Probably. However, if you have a choice, there are other options to consider that might work better for you.

First you have to deal with the problem. The radiant heat gain from the sun can be a huge problem when direct sun or reflected solar radiation from white clouds gets into the house for a substantial amount of time during the day.

If you were about to build a new house, I would tell you that proper orientation of the home to minimize windows on the east and west and to block the sun on the other walls is a top priority.

If the house is already built, then the key words are shade, shade and more shade. Unfortunately, this shade can cut down on that view that you like so much, so what's best for energy and comfort is not always what's best for the view.

The idea with having shade outside the home is to stop the sun before it ever gets inside. Trees, fences, roof overhangs and other building strategies can do a good job, as can awnings and screens.

Maybe you still love that view, don't want to give it up and don't want to spend the money on any of these other strategies. In that case, window tint can be a good alternative. You need to look for a tint that will block more heat than light.

When reading the product information on the packages, look for a tint that has a VT or TV (the visible transmittance number) higher than its SHGC (solar heat gain coefficient) or SC (shading coefficient).

The higher the VT, the more light gets in. The lower the SHGC or SC, the less heat gain that will get into the house.

Follow this recommendation and the tint will allow as much light as possible into the house during the day and block as much radiant heat as possible during this time. You've got to look for balance in these numbers. Some tints that do a great job of blocking the sun's heat, for example, will make the house too dark inside.

Don't let the terms scare you off, because this really is a lot easier to do than it sounds. The ratings on the tint will let you know how much light or heat is involved, and you can compare different products to select the right one for your needs.

Ken Sheinkopf is director of development for the Florida Solar Energy Center. Write to him at the Florida Solar Energy Center, 1679 Clearlake Road, Cocoa, FL 32922.