I have used Abacus for several years now, including yearly HVAC inspections, installation of a new HVAC system ~4 years ago, whole house re-piping 2 years ago and help with some electrical problems late last year. All their work was exceptional and done as explained and as I expected. In all cases, the technicians that came out were outstanding. Additionally, the technicians were knowledgeable, professional, very informative, and answered all of my questions. I highly recommend Abacus for all work that they perform.