The person who built this house used a hot water heater to supply hot water to a radiant floor heating system. It was set up wrong and the hot water heater eventually burned out from short cycling. Alex from OHBCS was the only contractor out of about 6 who showed up who correctly identified that I couldn't put in a high efficiency boiler due to the small gas feed line. They replaced the hot water heater, vented it properly to the outside, separated the radiant floor water loop from the drinking water in the tank with a proper non-ferrous pump and heat exchanger. They were knowledgeable, efficient, and stuck to the budget they had provided. Everyone else was trying to sell me a wall mount high efficiency boiler that wouldn't have worked do to lack of sufficient volume of gas. Current solution works and my water doesn't taste terrible anymore.
There was one small problem with the hookup of the thermostat, but they came back quickly and fixed it with no grumbling or additional charges.