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Here’s some terminology and things to look for when buying windows:

Glazing: the actual glass in the window is called glazing. Many homes and older buildings have just a single pane of glass. This is traditional style, but not energy-efficient.

R-values: the amount of heat a window loses through its glass panes. Higher R-values mean more energy efficiency. An R-value of 3 is very desirable.

U-values: the level at which a window conducts heat. Inverse of R-value, the lower the U-factor is desirable. Living in our wintery climate makes it desirable to have strong R-value and U-value ratings to conserve energy.


Solar Heat Gain Coefficient (SHGC):

SHGC measures the amount of solar radiation transmitted through a window, expressed as a number between 0 and 1. The lower the SHGC, the less solar heat the window transmits.

Low-E: aka Low-emissive traps heat by placing a thin coating on one side of the glass to reflect heat toward the outside in the summer and keep heat inside the building in the winter. This maintains more consistent temperatures year-round for comfort and energy savings. Carpet and furniture are also better protected against UV rays and color fading.

Glass types:

Annealed glass: it is slowly cooled to relieve any internal stresses. It will break off into large sharp shards when broken and therefore is not considered a safety glass. Annealed glass is a great fit for table top glass, cabinet door glass, and windows that do not require safety glass.

Tempered glass: aka toughened/safety glass. Created by the use of chemicals and heat, these treatments balance the internal stress rating of the glass, which results in increased strength and unique breakage. Tempered glass breaks into small, square pieces and is designed to be 4 – 6 times stronger than non-tempered. Tempered glass is great in instances of high traffic, but it does have a couple drawbacks:

  • Tempered glass cannot be cut once it has been tempered – so be sure to check your dimensions before ordering.
  • The edges are the weak point of tempered glass – if they come in contact with too much force or pressure, the whole piece will explode.

Take a look at the video below to see more details