Environvent totally messed up the installation, turning up over 2 hours late for a booked appointment, by which time my roofer who was to fit a roof vent on your instructions gave up and left. Environvent eventually completed the installation and provided their own roofer as mine was booked elsewhere for several weeks and refunded my out of pocket expenses for the cost of the aborted visit by my roofer, so have redeemed themselves to a certain extent. There was a terrible lack of communication amongst all concerned and I had to continually chase and enquire re progress. There was a large amount of stress caused from trying to manage the problem from my home overseas. Having had several installations done in the past with excellent service. This last install was most disappointing.