Good for the system's life cycle.
I first used Donmar Company 6-7 years ago when I was shopping for a new system. They installed a brand-new, complete HVAC system for my house. They paid attention to what I wanted and needed, and they did things right. Everything turned out exactly as I expected.
I have a maintenance contract with Donmar, so I have continued to use them and everything has been fine. I like the fact that they are a small company and Don knows what's going on. He talks with his crews all of the time and knows his people and customers well.