GREENSBORO, N.C. — It makes sense, if you shut a vent in a room or closet you don’t want to be heated or cooled, it should save you money for not heating or cooling that room. Nope. That’s not how your standard HVAC works.
Duke Energy emails out power conservation recommendations to customers. Kenneth, a 2WTK viewer, got the email and questioned what it said.
Do you know that closing registers/vents in unused rooms will not lower your heating and cooling bills? Closing vents will often cost more than leaving them open.
How can this be? We asked both Duke Energy and a third party.
“When you close the vents you're actually increasing the air pressure in the ductwork in the AC/HVAC unit. So, whether you’re pushing hot or cold air that air pressure is pushing back on the blower trying to push that air through,” said Jeff Brooks of Duke Energy.
An HVAC technician at Duggins Mechanical Heating and Air confirmed to 2WTK, this is true. He said, even if you shut the vent, the air still goes to that room's ductwork and builds up and traps it there, it doesn't disperse it to the other room.
The expert from Duggins also said empty-nesters often shut off half the house vents when the kids leave, but he said that could end up damaging your HVAC system. The new systems have zones or manual dampers you can shut off so the air doesn’t even go to the area you don’t want to heat or cool.
If the closed vent doesn’t work, what does?
“Think about taking the heat down by one degree and using the ceiling fan to move the warm air around and that may help you feel warmer versus cutting off that one register in the room,” said Brooks.
And this is low-tech, but Brooks says you should open up the blinds on the sunny side of the house during the day, it warms the room like a greenhouse type effect. Then you want to close the blinds on the shady side at night, this helps to keep the warmth in.