In message , Capitol
writes

My experience is that externally mounted sealed units mist when the
seals fail. PVC does lose it's shine, but who cares? My units still are
white after 35 years. My aluminium windows are 40 yrs old and the
white paint finish is still as good as new.

OK. Will see me out, then:-(

I think we have covered this topic. Thanks.

--
Tim Lamb