CCH replaced an old gas boiler in our house (they installed it a long time ago) with a new, high efficiency boiler. Three guys worked on it steadily for 3 days (which was their original estimate), seemed very competent and knowledgeable about all the details involved in the installation. They were also nice guys, answered all my questions, accommodated my request to put the new boiler up on concrete blocks to avoid possible water on the basement floor, explained how to use the new thermostat, wore booties and (COVID) masks whenever they were in the main part of the house. We feel that we got good advice about the choice of new boiler (the salesman was also very competent and helpful), and are happy with the result.