A field study of combo heating systems in Canadian single-family buildings

This study presents a field study of the performance of three multi-zone gas-fired comboheating systems that provide space heating and domestic hot water in three new single-family houses in the Greater Toronto Area in the Province of Ontario, Canada. Two systems are composed of a gas-fired condensing tankless water heater integrated with a smart air handling unit, while the third system is composed of a gas-fired condensing combi boiler integrated with a smart air handling unit. The performance of the three combo heating systems was monitored, analyzed and evaluated over one heating season. The gas consumption of the three systems were compared with traditional gas-fired heating systems (composed of forced-air gas furnace and gas storage tank water heater). Results showed that combo heating systems tested in this study are reliable, met the peak space heating load, improved the indoor thermal comfort by providing two independently controlled temperature zones and achieved significant gas savings compared to traditional natural gas heating systems. The annual gas consumption and greenhouse gas emissions of the combo heating systems tested in this study are less than the traditional gas-fired heating system (forced-air gas furnace and gas storage tank water heater) by up to 29%.