Why do most cars have lines on the back window?

Question

I've noticed that most passenger vehicles have horizontal stripes or lines on the back window. I'm wondering why this is.

Okay I get the idea! Why doesn't the FRONT window need the lines then?

Answer 1

The rear lines are metal strips that heat up when electrical current tries to travel through them - the electrical resistance causes the heat.

On the front windshield, we blow warm air instead. This is partly because warm air is easily accessible - since the engine is close by. Also, the lines would make driving a bit harder, as you would have to look between them to see the road. This is not a big deal in itself, but it throws you off a bit when you realise that the lines aren't even with the horizontal lines of the road, and they emphasize how uneven your car is in relation with the road. I have driven with defrost lines on the front windshield (most racing cars in Australia are required to have them, since most of the race cars have no heater or fan), and they can be very distracting. They keep taking your concentration away from the road - it took me ages to get used to them.

The other big reason for those lines on the back window is...its cheaper that way. Figures, huh?

Answer 2

Rear Defroster.

Answer 3

Normally these lines are wires to defrost the rear window of the auto.

Answer 4

Those are for rear defrost. The front windshield doesn't have them because it is first harder to see through than a clear glass, and because the front windshield has vents that can distribute air to the glass where the rear window does not usually.

Answer 5

Thats the rear defroster, they are actually strips of metal, and when you turn on the defroster, voltage is applied to the strips of metal and heats them up, similar to a toaster but not as intense and defrosts your window.

Answer 6

because, guy, the FRONT windshield has defrosters in the dash, AND those' lines' would inhibit forward vision, you know so you would not be able to safely drive your vehicle with those 'lines' in your vision. Actually. those 'lines' are heat strips that electrically warm the glass enough to melt frost, and/or snow. Hope this clears it up for you.

Answer 7

Rear window defrosters.

Answer 8

Those lines have a wire that is connected to them that defrosts your rear window. Either that or they are used by aliens to reflect messages to other civilizations.

Answer 9

Those are the electric wires for the rear window defroster. they get warm and melt the ice on the window.

Answer 10

To your second question, they are not in front because they dont need to be. You have the heat that you can direct to the front windows when you want them defrosted.