This week we’re retrofitting a very green heating system in a former summer cottage. Unico high-velocity low volume air duct system, low-mass Biasi boiler with Riello burner, flat plate high-efficiency heat exchanger for domestic hot water. The overall efficiency of the system should be in the very high 80s, and the best part? Our bid came in lower than another company’s proposal to install a conventional hot air furnace. Green doesn’t mean an arm and a leg. And it pays dividends for a long, long time.