Key Window Terminology
Key Replacement Window Terminology
Solar Heat Gain Co-Efficient is the rating give by the NFRC (National Fenestration Rating Council) defining a window's ability to prevent solar heat from penetrating the windows and heating the room. This is a very important number in our climate in the South. Read more in our SHGC article.Design Pressure/DP-Rating is a rating given to describe the wind speed pressure (usually stated in pounds per square foot) resistance, in both directions. The PSF number divided by 1.5 provides the DP Rating. A windows with a pressure rating of +- 60 psf equals a DP rating of 40. According to tables available from the International Residential Code and the Guidlines for Hurricane Resistant Residential Construction, a DP-40 is qualified for installation in wind zones between 140mph and 150mph. Many of the windows offered by All-Tex meet or exceed DP-40 specifications.
U-Factor In the South, we have the need to cool our homes more than the need to heat our homes. The U-Factor is a windows ability to keep heat in and is the inverse of SHGC. U-Factor is much more important in the Northern climates where there are more heating days.
Argon Gas is a colorless, odorless inert gas that is commonly used as a filling in the air gap between two panes of glass. This increases the thermal protection feature of dual pane glass. Argon is also used in fourescent lighting helping to make them cool to the touch.
Low-emissivity (Low-E) coatings are microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface primarily to reduce the U-factor by suppressing radiative heat flow and reduce the solar heat gain by reflecting solar energy before it penetrates the glass. The Low-E coatings are what is technically called "Spectrally Selective" due to it's ability to block certain UV rays and not others.
Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than soft X-rays. It is so named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the color violet (purple). UV radiation causes sunburn, fabric fade and skin cancers.
Dual Pane windows have two glass panes per sash separated by the spacer. Since the two panes of glass do not touch each other and the spacer (see below) prevents thermal tranfer between the two, you home's windows become more than twice as energy efficient.
The Spacer or Super-Spacer is the (usually poly or felt) framing on the inside of the windows that separates the outer pane from the inner pane. Since the panes do not touch each other, heat or cold can not transfer from one surface to the other.
Laminated Windows have the outer pane made up of two sheets of glass laminated together with a vinyl sheet. When broken, the glass pane stays intact much like a car windshield.
Thermally Broken refers to a method that creates a "break" (separation) between the outer and inner frames in both Aluminum and Vinyl windows. Heat and cold can not effectively transfer from one surface to the other.
