UPVC windows in hardwood frames

[tmv8848]

I have received conflicting advice with regard to fitting UPVC windows into existing hardwood frames. I am told that this is not recommended due to the expansion properties of UPVC and that they should only be fitted direct to the brickwork. I would welcome some advice on this.

[Petstrel]

How old are your existing frames? If too old, you should consider changing them as well just to be on the safe side.