Our house was built almost 15 years ago and the double glazed windows were made by John Carr, a company which is now obsolete. For the past year I have noticed that at least 3 windows seem to be steamed up inside between the double panes. It makes no difference if the ventilators are open or closed. It doesn't matter what the climatic conditions are either. The windows have a hardwood frame and we have the exterior painted about every 2 years. I know that most double glazing companies offer a 25 year guarantee, John Carr I think offered the same. I do not know if I have any redress and I am unsure which company took over and if they will accept responsibility. Can anybody advise?