One tactic for saving on energy use that homeowners often come up with is the closing of interior doors to rooms that are not in use. They may close off the vents in the belief that this will keep the room from being heated or air conditioned so that the energy that would have been required is saved, and the heating or cooling that is created goes elsewhere.
Unfortunately, a central HVAC system isn't designed to work this way. In fact, closing off interior doors creates pressure imbalances that put a strain on the system. Further, this action may even cause significant energy losses by leaking air to the outdoors.
What Closing Interior Doors Does
When you close interior doors, you are blocking airflow and pressurizing the room. Air that is contained in the room will seek a way to escape -- usually through minute cracks around windows, around baseboards or even cracks in the walls. All that escaping conditioned air is being lost to the outdoors, while the HVAC system is forced to replace that air, which can increase utility costs significantly.
What's more the replacement air will come from various sources: the chimney, furnace or water heater flue, for example. This drawing in of unfiltered air creates a draft that may contain dust, humidity and even carbon monoxide.
This unfiltered air may damage your home or harm the occupants through conditions that allow high CO levels, or the growth of mold.
Solutions
The system requires that air be allowed to move throughout the home as a means of regulating temperature. That means if you close the door, the air must still be circulated to and from the room for the system to work properly.
You could install a return air vent in that room. However, running ductwork could be expensive. Or, you might hire a licensed HVAC consultant to install a transfer grill above the door.
Another option is just to leave the door cracked a little.
For more on closing interior doors, contact Hartman Brothers Heating and Air Conditioning of Fort Wayne.
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 home comfort and other HVAC topics, download our free Home Comfort Guide or call us at 260-376-2961.