Yeah, I just bet ya it's for condensation.
Those double pane windows might be a newer type that have that cut out area, I don't
know. Maybe they are an older type.
Lots of people in the States of double pane windows but also a lot of people don't like
them and choose single. Like you said, the double pane windows tend to provide more
insulation. The bad is you can't clean the inside of them and condensation can form
resulting over time in foggy glass that can't be cleaned.
There's double pane windows in about half my house and I don't like them. They are
a newer install. They are tilt windows so it's easy for me to clean the outside by tilting
them inward. They don't have any kind of a hole or opening to them.
That's what makes me think your windows have that hole due to the Canadian winters
or something to do with how condensation may form in your house or area in which you
live.
I might try to google that and see what I can find, just out of my curiosity.
Well I don't have a metal roof at the house I own now. I would prefer it, however.
I'd be dead before a new metal roof ever began to rust and I doubt I would have
needed to do any maintenance to it. I will tell you where the real issues may be
with metal.
For starters, most home owners with metal roofing around here, have metal sheets
not metal shingles. Metal shingles probably are more expensive than the sheets. I
don't know but I would assume so. The main issues I see with metal sheeting is
making sure it is installed properly. It's best to go with a company that knows how
to properly install it. That's why we did not put the roof on ourselves when we
decided to go with metal roofing when we built a new house. We could have put a
roof on ourself but we couldn't do the metal. We had no experience in properly
installing the metal roofing. We did do it ourselves over our balcony as that was no
big deal placing the metal there.
The next issue is those metal rivets that are screwed through the metal. Well, I
don't know what they are called, I am saying rivets but they are probably called
something else. We have term for people that try and pass themselves off as
knowing what they are doing..... Jack Legs. There's a lot of jack legs out there
that work for themselves and will offer a cheaper rate. The problem is, they may
do a poor job so it's better to go with a qualified licensed company. If you go with
a jack leg and have problems, your insurance probably won't cover it. So those
rivets have to be sealed properly or they might leak.
I did not watch all this but this is metal sheeting that I am referring to and it looks
like they had a jack leg install it:
How not to install a metal roof - YouTube