Low E Glass Window Ratings

Light to solar gain.

Low e glass window ratings.

Low maintenance well insulated windows. By comparison low e glass coatings can have an emittance as low as 0 04. The white national fenestration rating council label. The ratio between the window s visible light transmittance and its solar gain coefficient rating.

In other words if there is a heat source inside your house or outside the glass bounces the heat from that object back away from the glass. Infinity from marvin is one brand that emphasizes energy efficiency. Such glazing would emit only 4 of the energy possible at its temperature and thus reflect 96 of the incident long wave infrared radiation. Choosing a window with a spectrally selective low e coating allows as much natural light to enter as possible.

The lower the u factor rating the more energy efficient the glass. With insulation we expect the higher r value to be a better insulator than one with a low. Low e low e2 low e3 windows. With the high cost of replacement windows and doors it s wise to know exactly what you re getting for your money.

Thus correlating to r values of 4 55 through 3 33. U factor is the rate at which a window door or skylight conducts non solar heat flow. 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. The 2 most important window and door labels.

Which should i choose. The ratings for glass are a bit more complicated than ones we are used to for insulation qualities. 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.

Types of low e coatings. Passive low e coatings hard coat. Here s what all those scientific terms and numbers about energy savings mean. Examples of windows with good low e ratings.

For windows skylights and glass doors a u factor may refer to just the glass or glazing alone. Choose an infinity from marvin window with low e glass and you can. This means you should look for windows with a vt rating as close to 1 as possible. 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.

But even doors with lots of glass like a sliding patio door have lower glass to frame ratios than windows or skylights. 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. The two labels you should look for. Nfrc u factor ratings however represent the entire window performance including frame and spacer material.

The coating is then applied to the glass ribbon while it. Okay so low e glass obviously is a special glass that has a low rate of emission. The passive low e coatings are manufactured using the pyrolytic process which creates a pyrolytic coating. Have nfrc ratings that meet strict energy efficiency guidelines set by the us environmental protection.

Window manufacturers product information may not list emittance ratings.