I live in Germany and we have a lot of snow on our roofs. In my room, I have a roof window, which is tilted such that the snow just stays on top of the window and I can't open the window anymore. This is very unpleasant because even if there is sunshine outside my room stays dark.

How do I get rid of the snow? Since it is a double glass window with low pressure in between the glasses, heat transfer via convection is very bad.

I thought about buying an infrared lamp and pointing it from the inside, through the window at the snow. But I am afraid that a lot of light will be absorbed/reflected by the glass and only a tiny fraction of the emitted energy will actually melt the snow.

Anyone a good lifehack to solve this problem?

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    Hi Luke, Welcome to Lifehacks. Infrared radiation passes through glass very well. That's the reason you feel the heat from sunlight shining through a window. Air space between glass panes are effective in reducing heat transfer by convection. That's the reason thermal windows are double glazed with an incorporated air gap between. – Stan Dec 4 '19 at 17:26
  • @ Stan, I am not so sure if that is true, I remember that glass has high absorption and pretty high reflection in the infra-red (I might remember wrong). Do you have a source where they actually measure the (complex) frequency-dependent refractive index of glass? The argument with the sun doesn't work since the sun emits most light in the visible spectrum and that heats you body as well (as does UV). – Luke Dec 4 '19 at 23:42

It's possible to buy magnetic window cleaning devices where you have a part that stays outside and you move it around the window using a handle that controls it magnetically.

You could leave one of these permanently in place on your window (at least during the winter) and use it to push the snow off the window without having to open it.

If the snow is very heavy then I doubt that you will be able to apply enough force to push it without breaking the attraction to the inside part - but at least the outside part won't fall off the window, because it will be held on by the snow.

With a little practice, I think this may work for all but the heaviest snowfalls.

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    This seems like a good idea, but does it work on double pane windows? – James Jenkins Dec 5 '19 at 14:51
  • Some of the ones on Amazon explicitly describe themselves as being suitable for double-glazing. Whether they work is another question, but you would think that today's rare-earth magnets would be able to do this. – Lefty Dec 5 '19 at 23:29
  • I would add the Teflon coating as well for ease of removal. – M.Mat Dec 6 '19 at 6:35

I have never tried this, but a hack could be to prevent snow from sticking in the first place by applying some Teflon® based preparation on the outside of the glass (when you can open it).

There are various commercial brands available, but whether they will work on sloping glass is something that you might like to try - later!

In addition, if you place an uplighter lamp under the window when snow is expected, there could be enough heat rising to melt any snow that falls before it can build up, by keeping the glass warmer than usual.

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I know the window is double-glazed to reduce heat loss, but it might only need a small rise in temperature to melt the snow as it falls, so it can run off. The outer pane's temperature has only to be kept above freezing.

I have actually used a light bulb for a similar purpose. The water tank in my chilly old flat was in the bathroom and in the winter I kept the door shut and a lamp burning to prevent it freezing. My neighbours laughed at me: he thinks he can heat a room with a light bulb. But they weren't laughing when the freeze came and they were knocking at my door with kettles and buckets. The light bulb made just enough difference to prevent the tank from freezing.

  • I would not do the lamp. Huge waste of energy. Only lightbulbs that would create enough heat are very inefficient. – M.Mat Dec 6 '19 at 6:37
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    @M.Mat but that's exactly the point: heat to melt the snow. Incandescent lamps are inefficient at producing light but it's heat we need, and that's why they are considered to be inefficient. And until the snow has gone, light too. In any case in winter that heat isn't "wasted" but means less heat needs to be produced from other room heaters. An uplighter seems ready made for the job. – Weather Vane Dec 6 '19 at 8:47
  • You miss the point. It’s inefficient because it’s a waste energy and not at all “green.” There are better ways to hack this problem than wasting energy resources. The Teflon and the magnet sweep ought to do it. It generate heat up at that window, a more efficient choice might be something like a candle heater. Super cheap and warms the room as well. – M.Mat Dec 6 '19 at 9:22
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    @M.Mat the energy is neither lost nor wasted: it does not magically vanish but heats the room anyway. And you are incorrect that candles are cheaper. A friend of mine thought she would save money by using candles instead of electricity, but when we did the sums she was wrong. You can't heat the window for free, except by the sun. – Weather Vane Dec 6 '19 at 9:24
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    @M.Mat I think you are misunderstanding energy efficiency. Incandescant bulbs are inefficient as a light source because 90% of the electrical energy is converted to heat. This has nothing to do with being green, in fact I would argue that candles are less green, as they produce carbon dioxide and soot. It is not "ungreen" to burn electricity, the aim is to get the electricity generation green, at the power station. If the lamp treatment works, a lower wattage bulb can be installed. – Weather Vane Dec 6 '19 at 9:47

The techy way to remove standing snow on a roof window or skylight, is with a flying drone or helicopter. Fly up above the window and deposit coal dust or other dark matter on the snow over the window, this will speed the sun's melting process by absorbing heat. Alternately you could use salt or other ice melt products.

Once the snow is melted you will want to open the window and clean it.


Perhaps you could apply Rain-X on the exterior face of the window (when it is not snowing of course), and it may cause the snow to drift off rather than settle. Normally it is used for deflecting rainwater on windscreens, which normally hold on to water in their surface imperfections.

I've experienced Austrian snow in Wien, so I know what Luke is talking about.

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