We have hardwood frames now but the seals are not working so there is a build up of condensation. The guy who came to give us a quote for replacing the units wrinkled his nose and keeping the hardwood frames and was recommending we go for upvc instead (he wasn';t very keen to do the job otherwise because it would take a lot of time). But I'm not sure brown upvc will stand up to the direct sunlight we get on our house. Anyone know of problems with this?