Ducting

[Newbie12345]

Hi just out of interest as I cannot find this information anywhere believe it or not , if I have a 5 inch extractor fan and a 5 inch carbon filter what size does the ducting have to be?? Would 5 inches be too small to fit? Or is that ok? Does it have to be an inch or 2 bigger? Please help many thanks

 

[Stealthboat]

Assuming the extractor fan hole is 5 inches in diameter and the carbon filter hole is 5 inches in diameter then 5 inch ducting will be fine, just use a bunch of duct tape.

 

[Newbie12345]

Nice one cheers for the quick reply buddy, been driving me round the bend trying to find the answer lol

 

[Rubby813]

HiNewbie 12345,
5"duct would be fine but if you would like to slow the air flow thru the filter (depending on the cfm of the fan) you may want toincrease the size of the duct to 6" or even 7".
If you could provide the cfm rating of the fan it would help. Also will extend the life of your fan (it runs easier, less static pressure.)
You dont want to move the air too quick. In general smaller duct moves less air at faster rate, more noise, less efficient.
Been doing heating and air conditioning for 25+ yrs.
Hope this helps

 

[Newbie12345]

Thanks for your reply well on the fastest setting its 340 M3/HOUR AIRFLOW RATE, it's a silent one anyway but the quieter the better I suppose would u still recommend a larger one say 6 inch ? Thanks

 

[Rubby813]

All depends on size of area to be used in. I use a 450 cfm inline fan ( cubic feet per minute) with 6 " duct and it works fine.
Look for a fan speed controller you can adjust your speed to suit your needs. They are @ $20.