When areas of your home are too hot or too cold, regardless of how you set the thermostat temperature, it would seem to make sense to open or close air registers to control the temperature in each room. Or, you may decide that unoccupied rooms should have air registers closed and doors closed to save on heating and cooling costs.
Here's why this is not a good idea to manage the climate in your home by selectively opening and closing air vents. When a central heating, cooling and ventilation system (HVAC) is installed in a home the amount of air volume carefully calculated to match the size of the furnace and air conditioner. By sectioning off areas of your home you will not make the the system work less, it will simply send the same amount of conditioned air to the remaining air ducts and vents throughout your home. Add to this the fact that a typical home's duct work loses 20-30% of conditioned air though leaks, and even more energy is being wasted.
Closing air vents and doors also increases the air pressure inside your home's air ducts. This in turn causes the blower fan work harder to force the air through the system. This will increase the risk of the AC evaporator coil freezing or the furnace heat exchanger overheating.
The important point to remember is that your home's heating and cooling is designed to work as a system
, using the air volume inside your entire home. Closing one or two air registers is not going to cause significant issues, but for each vent that is closed remember that the overall performance of your central heating and cooling system is being compromised.
If you have uneven temperatures in your home, have the system inspected by a qualified HVAC technician. They will check the size of your heating and cooling system, the duct work and other components to find solutions for rooms that are either to hot or too cold.
Have questions about your home's heating and cooling system? Give MR Plumbing, Heating, Air, Electrical a call, we're here to answer all your heating and cooling questions.