TL:DR - If you're looking for top-notch work and peace of mind, look no further. Long Version: My husband and I purchased our home in late 2018. It came equipped with a whole house (3500 sqft) micro-zoned radiant heating system. 16 loops, each controlled from a different thermostat. The tankless heater that provided heat to the system also preheated our domestic hot water. Our heater was an Italian-made product (Cosmogas) that was installed in 2005, and, at the time, sold by Capital District Supply. In the 2 years that we've lived here, it was clear this thing was going to give us trouble. A leaking mixing valve - leading to three service calls to different plumbing/hvac companies in town (Saratoga Springs) - resulted in hundreds of dollars spent on a clearly failing machine. I was billed for service calls even when no work was completed. Two other plumbing/hvac companies even told me they'd prefer to not take the job. After the last failed service call (a plumber replaced the mixing valve with the part I had already ordered and had on hand), we ended up with antifreeze from the heating system in our domestic hot water. We were at our wits end. I came across David Sellers Mechanical through an exhaustive Google search for hydronic heating experts in the tri-state area. I called and spoke with Rebekah, David's wife. I can't say enough about how empathetic, understanding and professional Rebekah is. David speaks highly of the work she has put into filling their website (davidsellers.com) with consumer protection information, and if you look for yourself, you'll see what I mean. I've never seen anything like it. It is pretty clear that this business is ethically sound. Rebekah told me David was out on his motorcycle but she would pass along my message. Not 10 minutes later, David called me from the road, and an hour after that, he was at my home. He listened to the long history of our issues, and walked through the system with me. By the end of his visit, he gave me a quote for replacing the tankless heater and getting our system running again. He also told me he could start work on it in less than a week. The following day, David sent me his contract. I responded with another request - to replace the electric hot water tank as well. He was able to agree to do so without changing the quoted/contracted price. This alone amazed me. Fast forward to later in the week. David and his colleague Kevin spent two full days removing the old equipment and installing a top-of-the-line, American-made (Lochinvar) combi-boiler and (Bradford White) electric water heater. The work they completed is impeccable. Every joint, every run of copper, every valve is installed with the precision and neatness of a true master of the trade. They left the area cleaner than they found it, and never hesitated to explain exactly how and why they were doing what they did. The bottom line is this: if you want the skill and craftsmanship of a master mechanic, you have to be happy to pay...not for the hours they spend physically completing the work, but for the many years they spent perfecting their skills. If I had to do this all again, I would have had David attack the problem from the start rather than throwing money at lesser technicians.