panels were intended to supply enough hot water (stored in a large well-insulated tank) to run both systems, we found that the electric backup heating system in the tank was using a lot of electricity. We eventually experienced hot water temperatures that were only lukewarm, probably due to the clogging of certain valves in the system. We were interested in replacing the electric backup with a gas powered system. Tony came to our house twice to evaluate our setup, which was very complex, and to propose modifications, including an on demand gas heater that could handle both radiant heat water and domestic hot water separately without mixing them. We learned from Tony that mixing the radiant and domestic hot water is not permissible under current building codes, although it was permitted at the time our original system was installed. He gladly answered all our questions patiently and in detail. We scheduled a time for the work to be done, and Tony and Enrique came and completed the job in the three days as planned. This required extending a 1" gas line, adding air intake and exhaust pipes through our foundation, reconfiguring the existing plumbing to feed into the new boiler as well as from the new boiler into our existing radiant plumbing. Tony and Enrique connected the new copper pipes to feed beautifully into and out of the new boiler. Among other things, they made sure that intake and exhaust pipes blended well on the inside of the mechanical room and outside of the house, added a filter so that the condensation exiting the system onto the driveway would be less acidic, and included an attachment above the mixing valve to remove the air bubbles from the system. They again answered all our questions. We are looking forward to using the new setup for many years. Wish we would have had Tony and Enrique install our original system.