They dispatch a technician to diagnose the issue but they arrive without any spare parts, despite them asking you what model HVAC system you have. Their diagnosis is accurate and fast since they know the common issues, but then they want to charge you a second visit when they come back with the parts, turning what can be a simple $ 100 part replacement into a $ 300 job ontop of their initial visit fee of $ 200. I run my own business too and can understand not wanting to keep parts in stock that might get stuck in inventory, but it is unlikely when you service 1000’s of customers with very common HVAC systems that you will get stuck with parts inventory.