Roof lanterns v sky lights for ground floor extension

[ey143]

We had planning permission approved for our extension which includes having 2 pyramid style roof lanterns, each 3m x 1.5m in size.

We recently saw some other friends houses who have similar size openings, however, they had flat roof lights instead of roof lanterns which we thought actually looked good because there was no obstructed views due to the frame profile like on a pyramid style lantern.

We're now a little confused as to which to go for. What are the main things to take into consideration when choosing between the two styles.

1. Will a flat roof light let in more or less light than a roof lantern (because a lantern has angled windows?

2. Is a pyramid style more likely to be colder as air is occupying the space above the roof but within the lantern?

3. Is a lantern more likely to leak than a flat plane of glass (roof light)

Any other thoughts, what would people here go for?

 

[^woody^]

I'd say no to all of those.

 

[ey143]

Why

 

[^woody^]

A rectangle hole in a ceiling lets in the same amount of light if its got one or twenty panes of glass over it.

Similar principal for it being colder. There's a small but insignificant amount of extra air space, which is not even worth thinking about.

It's as likely to leak as any other roof or roof window. It all depends who is fitting it.

 

[SimonH2]

A pyramid lantern has more glass area (an hence more heat loss) than a flat pane of glass. The air space underneath is irrelevant.

As for leaks, that's really down to whether it's designed and installed properly.

 

[noseall]

It's as likely to leak as any other roof or roof window. It all depends who is fitting it.

Probably the most relevant of the three sentences.

These installations are so easy to get wrong. There is a lot of care needed when installing this type of roof, right from the outset. Hope that you have a conscientious builder.

 

[OwainDIYer]

roof lanterns you can have ventilators or openers on the sides, which can be open even when it's raining. Lanterns look a lot better on a traditional property.