Roof windows in an energy-saving and passive house.
I will admit right away - I do not like roof windows and hence maybe this entry will be considered by many to be too biased, for which I apologize in advance.
Why I don't like skylights?
1. Losses through the roof window are greater than those through normal windows due to the upward movement of warm air (some argue with this claim).
2. Normal, warm installation of roof windows is a big problem. A thermal bridge at the junction of the frame will always be more difficult to minimize than in the case of traditional windows. A skylight is simply a hole in the roof, it's a break in something, which is supposed to be an airtight coating. A proper roof window installation is a decent team - again a higher cost.
3. Roof windows with a heat transfer coefficient characteristic of energy-saving and passive construction are horrendously expensive. As someone has counted many times - this expense does not pay off. For example, recently I saw quite reliable calculations, where the economic account was like this: By paying extra two thousand for a "warm" roof window, we save (gas heating) 15 PLN during the heating season. Almost like that, why not take the cheapest windows? You can, but first of all - inserting such a window in a passive or energy-saving house hurts , second - it eliminates e.g.. possibility of receiving a subsidy from the National Fund.
4. If you do not want to brown in summer, you must have external blinds on the window - additional cost, dark in the room - free
5. In winter, you will admire the snow for a long time, which will also effectively block the sunlight.
6. If you have not had the pleasure of cleaning roof windows yet, maybe try this pleasure with your neighbor first.
My recipe for avoiding these troubles and / or expenses is simple - skip the roof windows. However, if you have to insert them - count carefully or invest in more expensive ones, energy-efficient skylights will not be an expense, which will never pay back. If you have a lot of roof windows - then probably ask someone else what to do.
p.s. but that it wasn't, I myself have a skylight at home - one thing, in the bathroom. And the sky with stars can be seen beautifully through them.