was wondering if its possible to get insulated pvc windows,i know timber windows do that purpose but i dont intend to be painting windows in years to come even if it is every 5-7yrs and also they're very expensive the price of building materials i'm told has got very high which brings the build price up,between upgrading insulation etc i dont think maybe 10k or so extra on windows makes sense,it'll never pay back.if there,s no such thing as insulated frames can anyone recommend good u-value pvc windows at a reasonable price.senator say there's are a u-value of 1.7,rang quite a few but company's in the north east but no real answers.