Gottfried Green

The big slider windows are in and they look gorgeous. Here's the skinny on the numbers above.

A low U-factor is useful during cold days when heating is needed. A low U-factor is also helpful during hot days when it is important to keep the heat out, but it is less important than SHGC in warm climates. Select windows with a U-factor lower than 0.65 and preferably lower than 0.60.

Select windows with a SHGC of less than 0.40. A low SHGC is the most important window property in warm climates.

Select windows with a higher VT to maximize daylight and view.

For this climate the concern is mostly to keep spaces cool so the rules are different. These sliders allow only 39% of solar radiation through. Also to point out, it is winter now and that small amount of warming in the bedrooms could benefit us as we use the bedrooms in the evening when the temperatures drop. I have to experience this to really know but I think by summer the sun will start to set behind the tall trees that sit on the northwest corner of the house. (Right now the winter sun is setting more towards the southwest corner.) This could help shade that area from summer sun which would have a more severe effect on comfort and AC use.

Labels: materials