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Can I Save Money on Heating by Shutting Vents in Empty Rooms?

piles-of-large-currency-billsIf you use a furnace or heat pump to warm up your house, the heated air travels to the various rooms through ductwork and then out vents. Most vents have levers on them allowing you to adjust the louvers behind the grill. This way you can direct which way the air flows when it first comes out of the ventilation system. In fact, you can adjust the louvers to lie flat, shutting off the ventilation opening.

Does this mean that you can shut off airflow into an unused room by doing this? And is this a way to effectively reduce energy costs during the summer?

No, This Will Not Lower Your Heating Bills—Quite the Opposite!

First, closing the louvers will not fully seal off the vent; some air will escape around the edges. But this isn’t the main problem with closing off the vents. The big problem is that shutting vents will create an increase in pressure in the ventilation system and place higher strain on the blower motor. It doesn’t matter if the home has a variable-speed motor that adjusts itself (this is known as an electronically commutated motor, or ECM) or a fixed-speed motor (permanent split capacitor motor, or PCS). Trying to seal off rooms with the vents will make the motor work harder against the higher pressure—and that means energy bills will go up, not down!

There’s another serious issue with closing room vents: it can cause a furnace to overheat and shut down because of the trapped heat, and it can cause the coil of a heat pump to start freezing up. Both are major problems that will bring your winter indoor comfort to a dead halt.

There Is a Method to Control Which Rooms Receive Heat

To shut down the flow of heat to one or more rooms without a pressure increase and subsequent damage to the system requires zone controls. A zone control system is a way to divide up the ventilation system into separate “zones” (such as the upstairs and the downstairs, or for each room in the house) that can be closed off from receiving heated air. (It also works for the air conditioning system in summer.)

For zone controls to work, professionals must install a series of dampers into the ducts that seal them off, and then link the dampers to local thermostats. Each thermostat in turn links to a central panel. Most of the time, the blower motor must be replaced with an ECM motor so the system can modulate pressure within the ducts as the dampers shut down. The system operates so that air is directed where you want it to go, but without creating pressure spikes that can damage the blower or heater.

An effective zone control system allows you to manipulate comfort throughout your house so that you not only save money, but to also eliminate hot and cold spots and prevent family squabbling over where to set the thermostat. So forget about tampering with the vent grills: find out more about going with zone control.

If you’re interested in a zone control system in Skokie, IL or elsewhere in Chicagoland, contact our office and talk to one of our HVAC professionals.

Malek Heating & Cooling: Serving the Chicagoland area since 1998.

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