What is Low-E glass?

than normal windows. So if you were to stand outside in sunlight on a normal sunny day, you're being exposed to three different types of light. There's infrared light, visible light, and ultra violet light. When you're inside and looking out through a window, you really only need to see the visible light in order for the window to do its job. The window can go ahead and block all the ultra violet light and all the infrared light and you'll still

see the same thing through that window. The advantage of blocking the ultra violet light is that it prevents color fading and things like your rugs and your furniture and whatever you have hanging on the wall. The advantage of blocking infrared light is that it keeps summer heat outside the house and it helps keep winter heat inside the house. In other words, it improves the energy efficiency of the window. There are articles on the web that demonstrate the difference

that low e glass can make to winter comfort. For example, let's say it's zero degrees outside and the wind is blowing at fifteen miles, so it's cold and it's windy, and you were to look at the temperature the glass inside your house. If you just had a normal single pane of glass and you took its temperature, it would actually be at twenty six degrees would be below freezing, and you could have frost forming inside your house. Obviously, if you were to stand next to that window, it's

gonna feel cold because it is cold. It's it's lower than freezing. If you were to put in normal double paned glass and measure the temperature of the glass, it would probably be at about thirty five degrees, just above freezing. If you stood next to that window would still be cold. Now there's two types of low E glass you can buy. There's hard coatings, which is a very very thin, transparent

layer of tin on the outside of the glass. If you were to stand next to a hard coded low E double pane window, that glass would be at about fifty degrees Fahrenheits something like that, so it's better. You know, it's warmer than the glass from a normal double paned window or from a single pane window. By a long shot. It would still feel cool standing next to that window,

but not nearly so bad. And then there's another kind of low e called a soft coating, where they put a very thin layer of silver on the inside of those double paned windows, so the space between the panes they put a very thin silver coating there, and when they do that, the windows glass on a zero degree day outside is above sixty degrees. It's you know, nearly the same as the room temperature. So if you were to stand next to that window, you'd feel a slight

difference in temperature. But that low e window with that silver soft coating on the inside of the glass, creates a window that is practically as good as the wall. It's just a very good insulating window. So you can see there's a huge difference between just a single sheet of glass and these low e double paned windows. That tin coating, as I said, is known as a hard coating.

The over is known as soft. Obviously, silver is better, but tends to be slightly more expensive, and it pays to know the difference, because if you can get a silver coated window of soft coating at a decent price,

it's gonna have better insulating properties. That same kind of technology, by the way, is how they make one way mirrors, the kind of glass you see in an interrogation room or something like that, where it looks silver on the side where the prisoners sitting, and it looks clear on the side where the investigators are sitting and watching the prisoner. It's just that the coating on these low e windows is much much thinner, so it doesn't have that mirror

look to it. It's just helping to absorb that infrared light as it's going in and out of the window. One thing to keep in mind is that these metal coatings on the glass actually do reduce some of the

visible lights. So when you look out the window, you aren't really going to be able to tell it with your eyes, but if you were to is a light meter or something like that, there's less sunlight coming through because the metal blocks a little bit of it in the same way that a one way mirror blocks light. That metal reflects some of the visible light as well, and you might get fifty less visible light through a low e window then you get through a normal window.

Like I said, it looks the same to a human eye, but if you have house plants, it's not going to look the same to them. If you're replacing a single pane of glass with these fancy double pain are gone filled low e windows, plants inside the house are going to see a decrease in sunlight, and you may want to take that into account. You probably want to have lower light house plants inside your house if you're gonna

put in low e windows. For more on this and thousands of other topics, does that how stuff works dot com, and don't forget to check out the brain stuff block on the house stuff works dot com home page. You can also follow brain stuff on Facebook or Twitter at rastaff h s W