Speaker 1: Welcome to Brainstuff from house stuff works dot com where
Speaker 1: smart happens. Hi Am Marshall Brain with today's question what
Speaker 1: is low e glass? So if you were to go
Speaker 1: today and try to replace the windows in your house,
Speaker 1: or if you were buying a new house and you
Speaker 1: look at the windows they've put in, you're gonna hear
Speaker 1: about low e glass, and the question would be is
Speaker 1: it worth the money? Because low e windows cost more
Speaker 1: than normal windows. So if you were to stand outside
Speaker 1: in sunlight on a normal sunny day, you're being exposed
Speaker 1: to three different types of light. There's infrared light, visible light,
Speaker 1: and ultra violet light. When you're inside and looking out
Speaker 1: through a window, you really only need to see the
Speaker 1: visible light in order for the window to do its job.
Speaker 1: The window can go ahead and block all the ultra
Speaker 1: violet light and all the infrared light and you'll still
Speaker 1: see the same thing through that window. The advantage of
Speaker 1: blocking the ultra violet light is that it prevents color
Speaker 1: fading and things like your rugs and your furniture and
Speaker 1: whatever you have hanging on the wall. The advantage of
Speaker 1: blocking infrared light is that it keeps summer heat outside
Speaker 1: the house and it helps keep winter heat inside the house.
Speaker 1: In other words, it improves the energy efficiency of the window.
Speaker 1: There are articles on the web that demonstrate the difference
Speaker 1: that low e glass can make to winter comfort. For example,
Speaker 1: let's say it's zero degrees outside and the wind is
Speaker 1: blowing at fifteen miles, so it's cold and it's windy,
Speaker 1: and you were to look at the temperature the glass
Speaker 1: inside your house. If you just had a normal single
Speaker 1: pane of glass and you took its temperature, it would
Speaker 1: actually be at twenty six degrees would be below freezing,
Speaker 1: and you could have frost forming inside your house. Obviously,
Speaker 1: if you were to stand next to that window, it's
Speaker 1: gonna feel cold because it is cold. It's it's lower
Speaker 1: than freezing. If you were to put in normal double
Speaker 1: paned glass and measure the temperature of the glass, it
Speaker 1: would probably be at about thirty five degrees, just above freezing.
Speaker 1: If you stood next to that window would still be cold.
Speaker 1: Now there's two types of low E glass you can buy.
Speaker 1: There's hard coatings, which is a very very thin, transparent
Speaker 1: layer of tin on the outside of the glass. If
Speaker 1: you were to stand next to a hard coded low
Speaker 1: E double pane window, that glass would be at about
Speaker 1: fifty degrees Fahrenheits something like that, so it's better. You know,
Speaker 1: it's warmer than the glass from a normal double paned
Speaker 1: window or from a single pane window. By a long shot.
Speaker 1: It would still feel cool standing next to that window,
Speaker 1: but not nearly so bad. And then there's another kind
Speaker 1: of low e called a soft coating, where they put
Speaker 1: a very thin layer of silver on the inside of
Speaker 1: those double paned windows, so the space between the panes
Speaker 1: they put a very thin silver coating there, and when
Speaker 1: they do that, the windows glass on a zero degree
Speaker 1: day outside is above sixty degrees. It's you know, nearly
Speaker 1: the same as the room temperature. So if you were
Speaker 1: to stand next to that window, you'd feel a slight
Speaker 1: difference in temperature. But that low e window with that
Speaker 1: silver soft coating on the inside of the glass, creates
Speaker 1: a window that is practically as good as the wall.
Speaker 1: It's just a very good insulating window. So you can
Speaker 1: see there's a huge difference between just a single sheet
Speaker 1: of glass and these low e double paned windows. That
Speaker 1: tin coating, as I said, is known as a hard coating.
Speaker 1: The over is known as soft. Obviously, silver is better,
Speaker 1: but tends to be slightly more expensive, and it pays
Speaker 1: to know the difference, because if you can get a
Speaker 1: silver coated window of soft coating at a decent price,
Speaker 1: it's gonna have better insulating properties. That same kind of technology,
Speaker 1: by the way, is how they make one way mirrors,
Speaker 1: the kind of glass you see in an interrogation room
Speaker 1: or something like that, where it looks silver on the
Speaker 1: side where the prisoners sitting, and it looks clear on
Speaker 1: the side where the investigators are sitting and watching the prisoner.
Speaker 1: It's just that the coating on these low e windows
Speaker 1: is much much thinner, so it doesn't have that mirror
Speaker 1: look to it. It's just helping to absorb that infrared
Speaker 1: light as it's going in and out of the window.
Speaker 1: One thing to keep in mind is that these metal
Speaker 1: coatings on the glass actually do reduce some of the
Speaker 1: visible lights. So when you look out the window, you
Speaker 1: aren't really going to be able to tell it with
Speaker 1: your eyes, but if you were to is a light
Speaker 1: meter or something like that, there's less sunlight coming through
Speaker 1: because the metal blocks a little bit of it in
Speaker 1: the same way that a one way mirror blocks light.
Speaker 1: That metal reflects some of the visible light as well,
Speaker 1: and you might get fifty less visible light through a
Speaker 1: low e window then you get through a normal window.
Speaker 1: Like I said, it looks the same to a human eye,
Speaker 1: but if you have house plants, it's not going to
Speaker 1: look the same to them. If you're replacing a single
Speaker 1: pane of glass with these fancy double pain are gone
Speaker 1: filled low e windows, plants inside the house are going
Speaker 1: to see a decrease in sunlight, and you may want
Speaker 1: to take that into account. You probably want to have
Speaker 1: lower light house plants inside your house if you're gonna
Speaker 1: put in low e windows. For more on this and
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