Clear area around vents
Furniture, carpets, and other objects can block vents and prevent heated or cooled air from traveling. This blockage makes your heating or cooling system work harder and prevents rooms from warming up or cooling down quickly. If you have forced air in your home, check to see that your air registers have sufficient room to breathe.
Good to know: Closing the registers in unoccupied rooms may not improve the efficiency of your heating or cooling system. Closing vents can increase the pressure in the duct system, causing air leaks from cracks or holes in ductwork to increase. If this air leakage occurs in unconditioned spaces, like an attic, crawlspace or garage, it can reduce any efficiency gains from not heating or cooling the unoccupied room.
Heavy dust on a particular vent may indicate leaks in that portion of the duct system. If you see this condition, inspect the nearby ductwork to find leaks you can seal with mastic.