Closing air vents is a popular strategy for adjusting air flow in the home but it s not necessarily a good one.
Closing off central air vents.
Closing vents will cause different problems depending on the type of blower.
Homeowners typically close vents in an attempt to redirect air away from unused spaces.
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.
The belief is that closing a vent will simply push the air onward to other parts of the home improving energy efficiency.
Your air ducts make it worse.
But when you close the registers in unused rooms the pressure builds and turns those small leaks into big problems.
In fact it could even cause your energy costs to increase.
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.
Thus your system becomes oxygen deprived.
This can increase your energy bills and even lead to premature breakdown of your ac if you close too many vents.
The average home already loses about 20 to 30 percent of air through minuscule leaks and poor connections in the ductwork.
When you shut off the vents you can increase the pressure in your ductwork which can back up into your hvac and cause issues.
Like the idea that cranking the thermostat all the way up or down heats or cools a house quicker the notion that closing some household.
As if a damaged system isn t bad enough closed air vents can cause ductwork to leak or burst.
As it turns out closing air vents in a home with a modern central heating and air conditioning system does little to save energy.
Taking a home system with 4 equal size vents and an attic leakage equal to one vent each moves 20 of air.
Closing vents disrupts this balance and creates pressure in your system which causes your air conditioner to work harder.
In a 2003 study the lawrence berkeley national laboratory discovered that register closing led to increased energy use.
The study also found that whatever benefit was derived from closing air vents was largely offset by increased duct leakage.
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.
What impact does closing vents have on an hvac system.
Closing one increases attic leakage by 5 and increases flow to the other 3 vents by 5 each.
Wasted cool air in the attic moves from 20 to 25 of the total but the closed off room is considered worth it.
