What You Should Know About Closing Air Vents in Your Home

Closing air vents in rooms that aren’t being used seems like a no-brainer. It’s got to save energy, right? Unfortunately, like many things that sound like simple common sense, the truth is more complex. Your HVAC system, including the design of the ductwork, is carefully matched to the output of the furnace and air conditioner as well as the temperature requirements of various rooms in the home. The calculations that ensure this are all based on the assumption that all vents in all rooms are in the open position. Here’s why closing any vents is a bad idea:

• Your HVAC system produces the same amount of heating and cooling whether all vents are open or some are closed. A furnace or A/C has no way to “know” that vents are closed and does not reduce energy consumption to compensate.
• Closing vents unbalances the system. Airflow volume into each room is adjusted with all system air vents opened. Closing some vents disrupts this critical balance. Airflow into certain rooms increases, potentially overheating those rooms, while other rooms receive less heat and are chilly.
• Leakage is exacerbated. Most residential ductwork leaks some conditioned air. Because the blower delivers consistent air volume, pressure inside the ductwork increases when supply vents are closed. This increased pressure forces more heated or cooled air out through even smaller ductwork leaks, resulting in increased energy loss, decreased indoor comfort and higher operating costs.
• Unheated rooms affect adjacent rooms. Heat energy naturally moves from a warm zone into a colder zone. When air vents in one room are closed and the temperature drops, the colder room acts like a heat sink, drawing heat out of adjoining rooms through uninsulated interior walls. This disrupts temperatures in the warm rooms, causing the furnace to run extended “on” cycles to meet thermostat settings and increasing energy costs.

At Sobieski Services, Inc., our goal is to help our customers in Delaware, Pennsylvania, Maryland and New Jersey learn more about energy and home comfort issues – especially HVAC and plumbing issues – so that they can save money and live in healthier, more comfortable homes.

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