How can you calculate the size of the ducts in an Air Condition system?

Answer 1

Hi: Here is a simplified breakdown for your question. I can get way more specific and into way more detail (but) if you ask someone what time it is,,, do you really want them to teach you how to build a clock? # 1... Assuming the application design criteria is for say ( an average home ) and you have pretty much establish the type and tonnage of the system you require to be fairly accurate then we can go one step further. Homes, Businesses, Churches, and in general a multitude of applications basically have basic design rules that vary from one to another. A important factor would be the speed of the air flowing through the ducts, vents, and returns. Air can get pretty loud rushing through a pipe or into a pipe via some form of vent or return. In general Churches require a very quiet air flow design and homes also need to be quiet though not necessarily as quiet as a church. Of course, a Bowling alley or bar with loud bands and such,,, ( well,,, not so quiet required ) Now you may be wondering ,,, hmmmmmmmmmmmm????? ,,,, soooooo,,, how do I get easy hands on and in general duct design sizes along with vent and return sizes for my application. The answer is fairly simple believe it or not. Use a factory design guide usually available from where you purchase your equipment. Kewl Huh !!! The return air grill or filter grill is basically like this,,, ( larger is better). Of course,,, within reason. Filters do a better job if the air flowing through them is at a slower rate of speed. ( Makes sense huh ! ) So, larger area will give you reduced air speed and not surprisingly quieter operation. So,,, look up the criteria that your unit has as to how many cubic feet a minute of air flow it is designed to work well at. Then take into account some area's or rooms simply will require % wise air flow than others to be comfy in for various factors usually refered to as heat load. common sense will tell you which areas will on average require more of your % of available systems abilities. If your still with me ( wow ) match all this up with your ductwork and grill supplier charts and recommendations for their products and viola!!!! ( Neat huh ? ) Remember,,,, this is a compacted answer,,,, so don't go puttin it under a microscope 10X on me. Honestly though,,, you'll be surprised how well things will work out though. Jimiwane