| When a fireplace is operated in close proximity to the house’s central thermostat, the heat introduced by the fireplace can cause the heating system to delay its normal cycle of operation, affecting energy consumption in the home. It is estimated that almost a quarter of Canadian homes have a gas-burning fireplace, many of which are used daily during the heating season. When a fireplace is operated in close proximity to the house’s central thermostat, the heat introduced by the fireplace can cause the heating system to delay its normal cycle of operation, affecting energy consumption in the home. As a result, the fireplace ends up essentially replacing the furnace as the main source of heat in the home. Not only is the fireplace usually less efficient than the furnace, but it also directs heat to a single room – and can leave other rooms cooler in the process. During the past two winters, researchers have used the Canadian Centre for Housing Technology’s twin houses to measure the impact of operating a gas fireplace on energy consumption and on room temperatures. Three different modes of fireplace operation were examined: continuous evening fireplace operation from 18:00 to 24:00 with the furnace providing continuous air circulation; continuous evening fireplace operation from 18:00 to 24:00 with no continuous air circulation provided by the furnace; and fireplace operation by dedicated thermostat. Additionally, the impact of fireplace pilot light operation was investigated. Evening operation of the gas fireplace heated the main floor family room, the location of the gas fireplace, well above the 22°C set-point of the furnace thermostat. During this time, furnace gas consumption and furnace fan electrical consumption decreased. However, evening fireplace operation resulted in an increase in total energy consumption (natural gas and electricity for fan operation) by 12.5 per cent for continuous furnace fan operation and 11.6 per cent without continuous fan operation. In addition to this, the temperature in the second floor bedroom furthest away from the fireplace dropped by up to 2°C in the evening. Operation of the fireplace by dedicated thermostat control resulted in an average increase in total heating system energy consumption of 9.8 per cent during the experiment. Despite this increase in consumption, the total heat output from the furnace and fireplace combined was 2.3 per cent lower. Because of the near continuous operation of the fireplace, temperatures in the bedrooms on the second floor were 1 to 2°C cooler than the rest of the house, on average. The pilot light also had an impact on energy use. It released some heat into the home and reduced furnace operation, resulting in an average increase of 5.0% in total energy consumption for heating. While other models of fireplace and other house layouts would likely give different results, this experiment highlights the potential for a gas fireplace to actually increase home energy use, and reduce room temperatures. This project was funded by Canada Mortgage and Housing Corporation. The Canadian Centre for Housing Technology is jointly operated by the National Research Council, Natural Resources Canada, and Canada Mortgage and Housing Corporation. The full project report is available at www.ccht-cctr.gc.ca/eng/projects/fireplace.html. Article sourced from National Research Council of Canada, Construction Innovation newsletter. December 2010 issue, Volume 15, Number 4 |
