They installed a roof system 4 years ago and one of the units never worked properly - at the time we were given excuses. We found out a week ago one of the ducts had fallen off and now the whole system is fine. I believe they would absolutely have known at the time of install because it is so radically different now to what it was but just decided not to fix it because it was in a tough location. Otherwise good but zero reply if you have an issue like this after install.