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.
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.
What impact does closing vents have on an hvac system.
The average home already loses about 20 to 30 percent of air through minuscule leaks and poor connections in the ductwork.
The study also found that whatever benefit was derived from closing air vents was largely offset by increased duct leakage.
As if a damaged system isn t bad enough closed air vents can cause ductwork to leak or burst.
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 vents will cause different problems depending on the type of blower.
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.
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 a 2003 study the lawrence berkeley national laboratory discovered that register closing led to increased energy use.
Wasted cool air in the attic moves from 20 to 25 of the total but the closed off room is considered worth it.
Homeowners typically close vents in an attempt to redirect air away from unused spaces.
Permanent split capacitor psc blower closing vents causes this blower to slow down because it can t overcome the extra pressure.
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.
Closing one increases attic leakage by 5 and increases flow to the other 3 vents by 5 each.
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.
This can increase your energy bills and even lead to premature breakdown of your ac if you close too many vents.
In addition this increased pressure places strain on your air ducts.
In fact it could even cause your energy costs to increase.
Why closing air vents doesn t work.
But when you close the registers in unused rooms the pressure builds and turns those small leaks into big problems.
