My neighbor just had her central AC system routinely serviced. She asked the technician, "if I close the doors to bedrooms not used and close the AC vent in each of those rooms, will I save money by directing the air to only the rooms I use?" He said it would actually cut down on efficiency because it would create turbulence in the duct-work. He went on to say, "trust me it's true, you don't want me to stand here charging you $1.50 per minute to explain why it's true." She asked me the same question and I begged off. Her feeling is, if she closes all the AC vents in her car except the one aimed at her, she'll get a blast of cold air and cool down faster. Her home system is an "old work" system, put in years after the house was built, hence one return located in the ceiling of the 2nd floor hallway and the thermostat located in the same area.
Any thoughts??

Systems are designed to operate with all the supply and return ducts being open and not obstructed. That is all there is to it.

Systems require a certain amount of air flow per ton of cooling capacity. Closing off vents will not direct the air that used to come from those vents to others. Reduce the air flow too much & the system will freeze up which can cause major damage to the compressor.

I agree with both above posts. Another reason not to shut off registers to certain rooms is: interior walls and doors are normally not insulated, therefore, not heating or cooling a certain room will somewhat be like heating a home with no insulation value. You will lose efficiency by not heating or cooling the complete home (all rooms) equally.

In a car, you have the advantage of getting nice strong blast of air right on your face. Not so in a home (unless you spend your time with your face against a supply register.) I won't go into the differences between auto and residential heating and cooling for the simple fact that I would have to charge much more than $1.50 per minute to do so, lol.

PS. I am a slow typer, so I believe you owe me about $4.50 for this info,,

I agree with both above posts. Another reason not to shut off registers to certain rooms is: interior walls and doors are normally not insulated, therefore, not heating or cooling a certain room will somewhat be like heating a home with no insulation value. You will lose efficiency by not heating or cooling the complete home (all rooms) equally.

In a car, you have the advantage of getting nice strong blast of air right on your face. Not so in a home (unless you spend your time with your face against a supply register.) I wont go into the differences between auto and residential heating and cooling for the simple fact that I would have to charge much more than $1.50 per minute to do so,,lol.

PS. I am a slow typer, so I believe you owe me about $4.50 for this info,,,

Do you take Pay Pal?

Thanks for the reply guys... I learned something today which is a good thing. I'll pass the explanation on to my neighbor. I'm sending you a check for $4.50. Go stand by the mailbox... should be there any minute. LoL

Thanks for the reply guys............I learned something today which is a good thing. I'll pass the explanation on to my neighbor. I'm sending you a check for $4.50. Go stand by the mailbox................should be there any minute. LoL

Good to see a sense of humor. One of these days, when & if I ever retire, I'm going to travel the country & collect all the coffee, cold beer, & fishing trips people say they owe me for helping them out online. ;)