Do vent blockers really work? Also, improving 2nd flr A/C with single zone unit?

[greent]

I've been having problems with my 2nd floor being too hot despite blasting A/C. It trickles out on the top floor and is high powered on the bottom. Hired someone to take a look and discovered I only have a single zone A/C system, so basically the top floor is always going to be hotter than the bottom no matter what.

I am trying to think of some clever ways to get the top floor effectively cooler without installing a window A/C. The ideas I've come up with so far are installing heat blocking blinds and LED lights upstairs. But also I've heard that those magnetic vent blockers could work (all my downstairs vents are on the floor, so it won't be a problem having them fall down or anything). But are these actually effective?

Also if anyone can think of any other suggestions, please let me know!

Thank you!

[HayZee518]

A/c

Is this central AC? Are there any ducts running up to the second floor?

[greent]

Is this central AC? Are there any ducts running up to the second floor?

Yes, it's central AC. There are ducts running up to the second floor. There are three output vents up there that I know of. There are two rooms upstairs, and there's one output vent in the bathroom and two others in the other room (a bedroom). I have not found a return vent, I don't know if there would be one up there?

Also if it's helpful, the top floor is about a quarter in size as the the bottom floor by area.

[pushkins]

If you close off or restrict the air in the lower level vents then you will in effect force more air to the open vents/registers. Yes those magnetic vent covers do work, so would just closing the registers.
The real problem is going to be that as cold air is heavy it takes much more effort from your air handler to push the cold air upstairs, that's most likely the issue your having now.
Ceiling fans are one idea to help circulate the air, or a small fan at the bottom of the stairs blowing air upstairs would help move the cool air up.

[HayZee518]

return air a/c

ok, you've indicated the three feeders for the cold air. you also indicated no return air. question: is there a central return in any of the floors on the first floor or a vented door allowing the air to return to the a/c location?
next would be the speed in cfm-s.
is the fan motor of sufficient size to push the air all that distance? are the ducts a typical 6 inch diameter and are they insulated? are there duct dampers in the 6 inch pipe at the distribution plenum?

[greent]

There is a return on the first floor.

There are no duct dampers in any of the ducts, I have wondered if this would be a good idea to install. I don't know about duct size, insulation or the fan motor power (sorry, first time home owner here).

I've found that after putting heavy textbooks on the vents on the bottom floor (save of course the return), the second floor is now much cooler. Closing those vents or registers wasn't sufficient, there was still a lot of air coming out of them. So now I'm hopeful the vent blockers will be a good solution, but I am also interested in the dampers, but I don't know how easy these are to install?

Thanks for all the help, everyone!

[HayZee518]

distribution dampers.

the "take off" boots off your plenum are rectangular to round ducts I take it. the feed dampers can be installed at the plenum but you need to take apart one joint to access the inside of the pipe. you drill a 5/16 inch hole to clear the stud on the damper. the damper goes inside the pipe and fastens from the outside with a lever and a nut. you move the lever to throttle airflow in that duct and lock it with the nut.