Central Air Conditioning Closing Vents

Closed vents increase pressure.

Central air conditioning closing vents. Homeowners typically close vents in an attempt to redirect air away from unused spaces. In fact it could even cause your energy costs to increase. You see your ac pushes out cool conditioned air through your ductwork and into your home. This causes a couple of problems.

Your furnace or a c runs longer. Leaking or burst ductwork. When you close vents pressure builds up in your ducts. So when you shut some vents you are messing up the balance of your ac system.

But this is an average. The average home loses 20 30 of the air blowing through it thanks to air duct leaks according to energy star. The ideal system also has low duct leakage. In a well designed system the blower moves the air against a pressure that s no greater than the maximum specified by the manufacturer typically 0 5 iwc.

But when you close a vent yes even just a few it increases the pressure inside the ducts. In a 2003 study the lawrence berkeley national laboratory discovered that register closing led to increased energy use. Before closing any vents in your home. Air pressure inside supply ducts increases in proportion to the number of vents closed and pushes still greater amounts of conditioned air out of existing leaks.

The only real difference with closing vent registers vs balancing dampers is the increased potential for losing conditioned air to an unconditioned space by closing vent registers. Many homes lose even more. Closing vents worsens that leakage problem because the extra pressure forces moreair out of those leaks. Environmental protection agency estimates that most homeowners lose 20 percent of the cool air they re paying for right through their home s ducts.

That means the ductwork was sized so that amount of air going into your air conditioning system equals the volume of air going out of your system. The typical system however is far from ideal. The belief is that closing a vent will simply push the air onward to other parts of the home improving energy efficiency. Closing air vents is a popular strategy for adjusting air flow in the home but it s not necessarily a good one.

Ensure that your ducts are properly sealed and connected. Through mechanical ventilation devices such as bathroom or kitchen fans that vent to the outdoors or heating ventilation and air conditioning hvac systems with a fresh air intake. That means you re paying 20 to 30 more than you should on your utility bills. Through small openings joints cracks and around closed windows and doors through a process called infiltration.