Unless you live in an old farmhouse full of leaks and drafts, shutting a room to save energy is likely to backfire. A study done by the Lawrence Berkeley National Laboratory found that closing off registers in select rooms actually was more likely to increase energy use in energy-efficient homes. How is that possible?
Home comfort systems are designed with supply registers and cold (or warm, in the summer) air returns in each room. So, shutting the supply vent and closing the door doesn't prevent air movement. Instead, the blower motor will continue to pull air back to the furnace from the closed-off room. This depressurizes the room, resulting in outside air rushing into the room via opening and cracks. This cold, untreated air eventually will infiltrate into adjoining rooms, forcing your furnace to work harder.
In addition, the warm air that's trying to bypass the closed register will likely leak out between the register and duct joint and heat the area beneath the floor boards and between the walls. Your home will still be producing the same amount of heat, but using more electricity and gas to do so. Similar issues occur during the cooling process in the summer.
If you close off too many rooms, you can actually damage your furnace. Newer high-efficiency furnaces are designed to fulfill the heating requirements of your particularly sized home. If you significantly reduce the square footage by closing off rooms, the blower fan could burn out. You could also cause the ductwork to freeze. This could lead to both inefficiency and lowered life expectancy for your ductwork.
If you will not be using some of the rooms in your home over the winter months, consider having a professional HVAC tech install a zoning system. This will allow you to close off the rooms without adversely affecting your furnace operation.
To learn about other alternatives to shutting a room to save energy, please contact us at Hartman Brothers Heating & Air Conditioning. We've been helping Fort Wayne area families like yours achieve indoor comfort since 1963.
Our goal is to help educate our customers in New Haven, Indiana and surrounding Fort Wayne area about energy and home comfort issues (specific to HVAC systems). For more information about energy savings and other HVAC topics, download our free Home Comfort Resource guide.
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