No. The window should be sealed and insulated between the wall/framing and the window regardless of the window type or material.

I was told that if you use these Aluminum Windows you would need to vent your roof and that your house cannot be fully encapsulated. A fully foam encapsulated house with these windows will cause them to "sweat".

Who told you that?

A custom builder that uses a window dealer who sells this Milgard product.

Just out of curiousity, did you ask him what if you used another aluminum window? I don't think I have ever heard that pitch before and am just trying to think of his possible logic in using it.

He claims that he has Aluminum windows himself. He did not mention the brand and he also said he has the thermal break within the frames. During the winter he if he does not open his blinds the frames will start sweating and sometimes the glass will have condensation. I guess due to it being cold outside and warm on the inside of the house. According to his window and door supplier they mentioned to him that if using the Milgard Aluminum Series Windows and Doors it is preferred to not fully encapsulate the house otherwise they will sweat. If i choose to go with this option anyway they will make me sign a waiver stating that I understood this and they are not liable for any damages this situation may cause.

Curious, what ended up happening in this scenario? Did you use this brand? If so, did you foam or ??? We are going to use foam insulation and I was looking into this brand of window today (have a partial quote in hand, waiting on some custom sizes to finish out the quote). First I've heard this and definitely want to be aware of any issues we should know of upfront. Thanks!

@ritim

The condensation resistance number will tell all. Aluminum windows are more prone to condensation Regardless if they have a thermal Break. Blinds can have that effect on any window but aluminum will have that effect even more do since the CR number .