Closing Off Central Air Vents

Permanent split capacitor psc blower closing vents causes this blower to slow down because it can t overcome the extra pressure.

Closing off central air vents. Homeowners typically close vents in an attempt to redirect air away from unused spaces. If it s a typical duct system with 60 higher static pressure than the maximum specified closing even one register could send the system over the edge. When you shut off the vents you can increase the pressure in your ductwork which can back up into your hvac and cause issues. Closing one increases attic leakage by 5 and increases flow to the other 3 vents by 5 each.

The study also found that whatever benefit was derived from closing air vents was largely offset by increased duct leakage. Taking a home system with 4 equal size vents and an attic leakage equal to one vent each moves 20 of air. Thus your system becomes oxygen deprived. Yes your system may be fine if you close a register or two in your home but the results will depend on how restrictive and leaky your duct system is.

As it turns out closing air vents in a home with a modern central heating and air conditioning system does little to save energy. In fact it could even cause your energy costs to increase. Wasted cool air in the attic moves from 20 to 25 of the total but the closed off room is considered worth it. Closing air vents is a popular strategy for adjusting air flow in the home but it s not necessarily a good one.

In addition this increased pressure places strain on your air ducts. Why closing air vents doesn t work. Your air ducts make it worse. Closing vents will cause different problems depending on the type of blower.

Closing vents disrupts this balance and creates pressure in your system which causes your air conditioner to work harder. But when you close the registers in unused rooms the pressure builds and turns those small leaks into big problems. As if a damaged system isn t bad enough closed air vents can cause ductwork to leak or burst. The issues your hvac experiences due to closed vents are like problems caused by dirty air filters including inadequate airflow turning off and on frequently and premature hvac breakdown.

This can increase your energy bills and even lead to premature breakdown of your ac if you close too many vents. What impact does closing vents have on an hvac system. In a 2003 study the lawrence berkeley national laboratory discovered that register closing led to increased energy use.