Low E Glass Window Ratings

Okay so low e glass obviously is a special glass that has a low rate of emission.

Low e glass window ratings.

Nfrc u factor ratings however represent the entire window performance including frame and spacer material. With insulation we expect the higher r value to be a better insulator than one with a low. Have nfrc ratings that meet strict energy efficiency guidelines set by the us environmental protection. The ratio between the window s visible light transmittance and its solar gain coefficient rating.

This means doors can provide more insulation than a window or skylight can. With the high cost of replacement windows and doors it s wise to know exactly what you re getting for your money. The lower the u factor rating the more energy efficient the glass. This is a fairly normal industry standard that has been around a good many years.

Many of the windows from this manufacturer are energy star qualified across the entire country regardless of climate. The passive low e coatings are manufactured using the pyrolytic process which creates a pyrolytic coating. Such glazing would emit only 4 of the energy possible at its temperature and thus reflect 96 of the incident long wave infrared radiation. Examples of windows with good low e ratings.

Which should i choose. Infinity from marvin is one brand that emphasizes energy efficiency. This may sound like a low insulating value but even the finest energy efficient windows today carry u values hovering in the 22 through 30 ranges. Thus correlating to r values of 4 55 through 3 33.

The coating is then applied to the glass ribbon while it. This glass works by reflecting heat back to its source. By comparison low e glass coatings can have an emittance as low as 0 04. For windows skylights and glass doors a u factor may refer to just the glass or glazing alone.

Types of low e coatings. Window manufacturers product information may not list emittance ratings. Choose an infinity from marvin window with low e glass and you can. U factor is the rate at which a window door or skylight conducts non solar heat flow.

But even doors with lots of glass like a sliding patio door have lower glass to frame ratios than windows or skylights. This means you should look for windows with a vt rating as close to 1 as possible. So in the winter months if you have low e glass in your home much of the warmth heat given off by the furnace and all the objects which the furnace has heated is bounced back into the room. Here s what all those scientific terms and numbers about energy savings mean.

The white national fenestration rating council label. Light to solar gain. It s usually expressed in units of btu hr ft2 of. The two labels you should look for.

Low e low e2 low e3 windows. Choosing a window with a spectrally selective low e coating allows as much natural light to enter as possible. The ratings for glass are a bit more complicated than ones we are used to for insulation qualities. The 2 most important window and door labels.

Low e glass allows visible light to pass through it but blocks heat generating ultraviolet light requiring less artificial heating or cooling to keep a room at the desired temperature.