There are going to be allot of varying opinions on this one but it's fairly simple to get in a good ball park. You want between 600 to 800 feet per minute of air flow so you need to know the CFM of your air handler and then you can calculate it this way.
Ftcube /min divide by Ft / Min = Ft square. At 1200 CFM for a flow rate of 800 Ft/min you get a result of 1.5 square feet which is 216 square inches. If you divide by 8 for the prefab 8 inch duct you need a 27 inch wide dimension or 16 X 13.5. Good luck on your project.
return grille size times 2 gives u the amount of cfms u are getting out of the return air grille, i.e. 10x10x2=200cfms...
quick down and dirty way is the size of your unit (example..4 tons) X 144= the square inches needed for the return vent size or the longer way Max air flow from unit (rated size) / 2.08 cfm/sq in= filter area needed
King size sheets will not fit on a Calfornia king size bed. The fitted sheet will fit but the top sheet will be 4" shorter. A king is 4" longer and a california king is 4" wider.
Honey, Calvin Klein shoes run true to size about as often as I run a marathon. It really depends on the style and your foot shape, so I'd recommend trying them on before committing. But hey, if you're feeling lucky, go ahead and order your usual size and hope for the best.
Return can be a noun or a verb.
The air is returning at a lower velocity, so you need a larger size duct.
The recommended return duct size for optimal air circulation in a residential HVAC system is typically around 1 square foot of duct area for every 1 ton of air conditioning capacity.
A 16" round flex duct will accommodate up to a 3.5 ton unit
Air return duct and filter grille size is dictated by the size of the unit (CFM) not the size of the house.
8x22 or8x24 duct
The recommended return air duct size for optimal HVAC system performance is typically 1 square inch per 1 CFM (cubic feet per minute) of air flow.
what is nomal size of pancreatic duct fir 60 years old male
that depends on what size your duct is as it will vary depending on duct size
When determining the appropriate return duct sizing for a residential HVAC system, factors to consider include the size of the HVAC unit, the layout and size of the home, the number and location of supply vents, and the desired airflow rate. It is important to ensure that the return ducts are properly sized to allow for efficient air circulation and maintain a comfortable indoor temperature.
Thoracic duct
Find 5% then half it
If it is the airflow that is making the noise, this is caused by undersized ducts. If you recently had your equipment replaced be sure the airflow is set properly for the size equipment you have. If it is, look into increasing the return air grille size. That may give you some improvement. If the noise is still objectionable the duct size will probably need to be increased.