Windows should they be taped?

[Ursidae]

People track everything...

Do as you like. I guess you didn't have any vapor barrier in the gap on the old windows. The point is to prevent water vapor from seeping out and risking condensation in the insulation. It’s mainly an issue in well-insulated houses.
If it's a new build, you do it by the book. If it's an old house, you have to do what works, for example, you can't connect to the plastic foil in the wall no matter what you do.
Not even the soft sealant will be 100% in that case since the rule is not vapor-tight.

In other words, tape is good, plastic sealing strip is probably better, and sealant is best. But it will probably work fine even without anything.

 

[Knalle10]

People track everything...

Do as you wish. I guess you didn't have a vapor barrier in the gap on the old windows. The point is to prevent water vapor from penetrating and risking condensation in the insulation. This is mainly a problem in well-insulated houses.
If it's a new build, you do it by the book. If it's an old house, you have to do what works, for example, you can't connect to the plastic foil in the wall regardless of how you do it.
Even the soft sealant won't be 100% in this case since the rule isn't diffusion-tight.

In other words, tape is good, plastic-coated sealing strip is probably better, and sealant is best. But it will probably work excellently even without anything.

Thanks for a good answer