My ac works poor on my second floor(as I wrote in my other thread). I heard today that I need some air vent adjustment and vent booster. Im open to any advice because Im not ready to buy new AC. Can somone explain to me how to do it? And how much does it help?

 

We can only see what you have written in this thread. Include all the information for this problem in this thread or include a link to the other thread you want us to see.

 

Booster fans are a band-aide that don't usually do anything beyond adding noise and using electricity.
Sometimes closing vents on the first floor can help but this will add noise, lower airflow and possibly cause issues with the system as well as cause unnecessary strain on the blower.
What you describe is the same problem everyone else with a single unzoned system in a 2 story house has. Added roof load for the second story coupled with hot air rising and a thermostat on the first floor.
Adding returns upstairs helps. Zoning would help. 2 separate systems would help. Running the blower constantly may help but this can increase space humidity by evaporating moisture on the evaporator back into the airstream being pushed back out into the space.
Simply replacing the equipment with no change to the ductwork likely would not do anything.

 

yeah. All you said is right. Not much too add. Im selling my house so I wont buy new AC. I googled this "duct adjustment". I see now that my friend meant damper adjustment. Pretty simple. According to google I have to just open fully damper for second floor and close or half close damper for first floor.

 

My basement isnt fully finished and ceilling drywall is not patched nor painted so I found already 6 levers(dampers if it is real name) on my ducts in hard to get spots. I dont know how previous owner wanted to adjust these levers for each season after finishing basement. Anyway i was hoping for some advice from you guys but since you dont say much Im about to test each duct lever and check which vent in which rooms it controls. I want to see if it is better if i halfly open all on 1st floor and fully open on 2nd floor.

 

I have a tri-level house and don't mess with any of the vents on the mid level but in the winter I close three of the six vents upstairs and in the summer I close three of the five downstairs. This works fine as long as the furnace or AC is running but without that, the hot air eventually goes upstairs and the cold down.

 

My ac works 24/7. I will try to close completely some ducts on 1st floor like you said. Basement has only 1...

 

I don't like the sound of the AC having to run 24/7 - that should only happen on the very hottest of days for your area. This makes me think something is wrong or the system is not sized properly.

 

Haha... No no. What i meant is that i set up thermostat on 74 degrees and never turns off. It works when it wants. Although outside unit is loud but i have to survive until next summer.

 

How to Optimize the Supply Air CFM Volume to & from the Rooms for balancing airflow to all upstairs rooms; in cooling mode, the Return-Air should also all come from upstairs.

You always want the highest static pressure on the supply-side at the diffusers to the rooms, while at the same time, as much as possible, reducing as much ‘resistance’ or pressure drops in the rest of the supply-side, which also includes using low pressure drop fittings in all of the supply side ductwork to optimize pressure at the supply-side diffusers.

You want to greatly reduce the airflow ‘resistance’ on the return-side to produce more static pressure and CFM airflow on the supply-side at the diffusers. Any airflow needlessly restricted on the Return-Air side reduces the air availability to the blower wheel blades, which ‘reduces’ the blower wheel performance and the airflow through the evaporator coil and to & from all the rooms.

You should also always have branch duct dampers installed so you can adjust the airflow balance, for example, to 2nd floor areas, where that is a problem.

Reducing all the return air ‘resistance’ possible on the return-side making any return ductwork as large as optimally possible, plus return-air filter areas as large as possible to reduce all return-side resistance and pressure drops possible, which will optimize supply-air CFM both to and from the rooms.

If use 1" deep filters use Purolator model P319 filters; can't see through them & have low resistance & good filtering qualities. Can order them over the Internet.

Very low airflow with some conditions, could lead to the freezing over of the evaporator coils resulting in possible severe compressor damages… If indoor airflow drops off, shut the outdoor condenser/compressor off immediately…!

Also, always check the temp-split of the air off the outdoor condenser compared to the outdoor temp, the 'Expanded Cooling Data' will show you what the temp-split should be at the existing conditions.

 

I understood a little. I cant find this filter model. I use 16x25x1 cheapest brand merv8 and change every month.

I have returns in every room. I can clean them or even remove these"shields" if it may help to take back more air.

I will test dampers. I dont know how many to close.

I also have 3x Flanders E-Z flow. They are grean and super thin. Are they better for summer. Are they low resistance?

 

Yep, that's normal - this is a trial and error process. Additionally, I used to close one more vent in the summer in the basement but a new dehumidifier changed the air down there enough I needed to open one more, so don't assume once you have a balance that it will always stay that way.

 

Ok. So I closed one and only vent in basement. After removing drywalls i found out that it was just a cut in dyct so air was blowing everywhere into the ceilling and down. I patched it compkwtely with cardboard and silver tape. Then I removed all drywalls from ceilling, found more levers on ducts. Then i closed 3 for first floor, 1 fully open, 1 half open. Then i fully opened 1 lever for second floor. I cant find more levers... for second floor. I have 2 bedrooms and and bathroom there. I vent in each room. Air blows differently in all three but way better way stronger. Now temp upstairs is 73-77. Thermostat is still set up for 74. We still use portable AC in bedroom just at night because we sleep with 2 small kids and at night it gets way hotter and humidity kills us. I think this room cant get cooler with 4 people inside. That is why my electricity bill is already $112.
I dont know if i can find better configuration for dampers but I still think bathroom upstairs has to have additional damper/lever because it blows super strong.