7.265
if the area given is 100 square inches you can use 10" by 10" duct due to a black art known as aerodynamics or compressible fluid flow, you will get the same back pressure in a 10" diameter round duct and a 2" x 50" duct considerably more back pressure a nice manufactured 90 will take as much back pressure as 50' of duct a tight curved 90 will take as much as 100 feet of duct fans have a curve that goes from maximum cfm at no pressure to minimum cfm at max pressure the fan will require the most power when cfm * pressure is highest simple as rocket science i guess
Air return duct and filter grille size is dictated by the size of the unit (CFM) not the size of the house.
You need 350 to 400 cfm per ton (12,000 btu) of cooling. So, divide your cfm by 400. For example, a 1200 cfm blower on an air handler could handler up to 3 tons. All calculations depend on your duct being the proper size for the equipment.
There are 400 cfm in 1 ton
24" round duct or equal. register should be about 2 cfm per sq. inch. or 800 sq. inches for 4 tons
7.265
if the area given is 100 square inches you can use 10" by 10" duct due to a black art known as aerodynamics or compressible fluid flow, you will get the same back pressure in a 10" diameter round duct and a 2" x 50" duct considerably more back pressure a nice manufactured 90 will take as much back pressure as 50' of duct a tight curved 90 will take as much as 100 feet of duct fans have a curve that goes from maximum cfm at no pressure to minimum cfm at max pressure the fan will require the most power when cfm * pressure is highest simple as rocket science i guess
answer is
~ 1000 cfm
350
To calculate the formula for duct sizing divide the room load by the whole house load. Next multiply those results by the equipment CFM.
1tr = 400 cfm
It depends. If your bedroom has a supply AND return duct, then no. If there is only a supply duct, and you shut your bedroom door, this pressurizes the bedroom and limits the CFM delivered into the bedroom. A room to room vent or duct would equalize this pressure and allow maximum CFM to be delivered from the central air/heat system.
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.
1 pa = ? CFM
Air return duct and filter grille size is dictated by the size of the unit (CFM) not the size of the house.