Andrew installed our furnace 3 years ago, under warranty, so we called when it stoped working this week, he came and checked for a while,furnace/ venting all - big ? Problem would call manufacturer to find a fix and return, told get heaters in meantime. Then, No communication, he returned 1 call after I called , emailed , texted ! deplorable customer service for 3 days . We then called CoreTemp who came within 30 minutes, checked it went and got the part and fixed sameday - thank you. Wll not be calling A-Z (NO) Comfort air again .