How can I block central AC from the basement so upstairs stays cooler? Is pressure an issue?

Question

Thanks for you answers so far.

Allow me to clarify some details:

The basement is a finished living space approx. 1500 sqft. The register vents are located overhead (in the ceiling pointed down), adjusted to the closed damper position and already covered with the typically available magnetic sheet.

Significant cold air flow still occurs, sealing the vents with tape and cardboard, as mentioned, may totally block the flow and force more cool air to the upper level, but will the increased pressure of creating a close to air-tight seal on multiple vents in the basement damage the HVAC system?

Answer 1

u can also turn your air unit fan to ON instead of auto and the fan will recirculate the cool air better

Answer 2

No offense, but might we assume you have a finished basement and use it as a living space? If not, I see no reason at all for it to have AC flowing to it.

   Certainly if you knew the capacity of the AC unit, or it was in the plan to have one large enough to do the job on multiple levels, a common rule would be 500 to 700 sq. ft. per ton, minimum.

   I guess I'm still confused about why DUCT a basement.

Just my two "sense"

Answer 3

Actually physics is the real problem. If you have vents in the basement by all means close them. But since cold air settles, (goes down) and basements are below ground,(insulated by the ground) they will be cooler than the rest of the house. Keeping the basement door closed will help as well. Good luck!

Answer 4

Ur baseman vents should have adjustable vents.  Just close off the vents and all the cool air should be directed to the vents upstairs.  If u don't have the adjustable type.  U can block it with cardboard/ and tape.

Answer 5

Your basement is cool not because of the AC works better down there, but because of the insulation of the earth, and that it doesn't get much sun. Blocking your vets downstairs won’t have a huge impact upstairs.

Answer 6

Look for magnetic vent covers, usually available at your local hardware store (Home Depot, Lowes, etc).  They are also available online if you do a quick search.

Several issues are at hand.

Hot air rises, while cold air settles.

The ground temperature (especially during the day) is colder than the ambient air temperature.

Air still leaks through "closed" vents when using the built-in damper.

If you simply seal off the airflow, yes, the pressure will force more air through your upper-floor vents, thereby cooling your upper floors more quickly, and saving your money by not running the compressor longer than needed.

Stay cool!