Can a lift-and-slide door be as airtight as a normal door?

We have one and will soon get a second lift-and-slide exterior door. I like them because sliding doors are not in the way - they are pleasant to operate ... and even people who are not familiar with the technology quickly get the hang of it. But every now and then I think about the fact that the system with the brushes can’t possibly insulate properly :eek: I have read that they are now very tightly sealed :) A comparison of the insulation effect of lift-and-slide and "normal" doors would interest me. I have been searching unsuccessfully for a while ... :rolleyes: Does anyone know a website where there is information about this?

Ours has a sealing rubber. It is airtight, at least according to the Blower Door Test, and that for a passive house. After 3 years, no drafts appear

Sealing rubber - yes, of course. When lowering the door, a gap forms at the top that somehow needs to be closed. You can only see the brush seals, but they alone can’t possibly make it airtight ... ... at least that’s what I assume.

A blower door test would probably whistle quite a bit in our 70s house ... ;) but if one spot is sealed, it’s already more airtight than if it drafts everywhere ....

We were told (new build) that lift-and-slide doors are never perfectly sealed and if placed on a weather-exposed side, a gutter must definitely be installed in front of them

A gutter "in front"?

Where exactly?
And: a gutter for what? Water?

I like them because sliding doors are not in the way

I think they are even very much in the way; after all, they take up half the width for the part pushed behind. My favorites are folding sliding doors or even better outward-opening hinged doors.

A comparison of the insulation effect of lift-and-slide and "normal" doors would interest me.

We had - in our own profile system designed many years ago by the now deceased company founder - triple glazing not available for the lift-and-slide doors; they had to make do with double glazing. That was one reason for the decision to become licensees instead of remaining manufacturers.