I've been a customer of The Duct Specialists since replacing my HVAC 5 years ago and have faithfully had routine maintenance twice per year since. My fall service was done in December (hard to get it scheduled with my crazy work schedule). After a very thorough evaluation, the technician had suggestions that would improve the comfort of the house, and improve air quality. One of the work items that I had done was to replace my attic insulation. It was not cheap and my hope was to see a difference in heating cost. After an extended power outage (40 hours with an exterior temperature as low as 8 degrees), I can vouch for a more valuable benefit. When the power came back, my house was 45 degrees. Many of my neighbors said their homes were in the 30s. I think the improved insulation kept my house, my pipes safer. The process for all the work done involved multiple crews over several days but they were all professional, cleaned up after the work and make sure I knew when they'd be back to finish.