Inline fan for 2x4x6 the m3/hr - cfm trap

[Clem Fandango]

Hi,


I was shopping around for a inexpensive inline fan for my 2x4x6. I read that the formula to work out the flow volume needed was 3x the volume in feet so.. for the 2x4x6 - 140 cfm. It's also advisable to get a bigger fan than minimally required so for my tent I'm thinking 200 cfm.

NOW, as I live in a country that doesn't insist on using obsolete units of measurement , I have to convert that volume to metric. I almost pulled the trigger on a 220 m3/h fan before it dawned on me that that may be incorrect.

So can the wise heads here please confirm for me that I'll need an inline fan with a metric flow volume of about 340 m3/h?

Conversion factor 1 ft3/min = 1.699 m3/h

Thanks in advance

 

[Olderfart]

Hi,


I was shopping around for a inexpensive inline fan for my 2x4x6. I read that the formula to work out the flow volume needed was 3x the volume in feet so.. for the 2x4x6 - 140 cfm. It's also advisable to get a bigger fan than minimally required so for my tent I'm thinking 200 cfm.

NOW, as I live in a country that doesn't insist on using obsolete units of measurement , I have to convert that volume to metric. I almost pulled the trigger on a 220 m3/h fan before it dawned on me that that may be incorrect.

So can the wise heads here please confirm for me that I'll need an inline fan with a metric flow volume of about 340 m3/h?

Conversion factor 1 ft3/min = 1.699 m3/h

Thanks in advance

Spot on. Sorry for the earlier error if you spotted it. I missed the minute vs. hour difference in the ratings.

Having said that, I am skeptical about a tent needing air replacement every 20 seconds. I doubt that CO2 levels decline that quickly, and providing a steady supply of CO2 is the primary reason for air exchange if temperature and humidity are dealt with. I would be interested in data on how CO2 levels change in a grow tent in response to ventilation, but have not run into any.

Good luck with fan shopping.

 

[JSH1973]

I have a 2x4x6ft tent and use an AC Infinity 6 inch so that I can run it on setting 2 for zero noise, it's not mega expensive, about 120 usd/euro

 

[Capn Bligh]

NOW, as I live in a country that doesn't insist on using obsolete units of measurement

I prefer the term "legacy" units. More in line with optical drives on computers.

 

[Olderfart]

I have a 2x4x6ft tent and use an AC Infinity 6 inch so that I can run it on setting 2 for zero noise, it's not mega expensive, about 120 usd/euro

Me too. The larger filters likely last longer per price as well.

 

[tronN00dles]

Another vote for a 6" fan from me.

I think it's better to oversize your fans/filters. It's not just about calculating CFM requirements based on the size of your tent -- you need to consider your ambient temperature and humidity. I live in a humid environment, so I need extra fan power to clear the moisture out of my tent.

I have a small 20" x 36" tent in my closet with a 4" AC Infinity inline + filter, which is rated for ~200 CFM. While I get great air circulation, it can struggle in the summer to keep the humidity in check without an extra dehumidifier. I'm in the process of upgrading to a 2 x 4 tent, which based on typical CFM calculations, a 4" fan would suffice. However, since I wish I had a slightly bigger fan in my 20" x 36" tent, there's no way I'm sticking with a 4" for the bigger tent.

Also, bigger carbon filters will probably last longer; and even if you really only need ~200 CFM, I'd rather run a 400 CFM 6" at half-speed than a 200 CFM 4" at full speed.

-tronN00dles

 

[Clem Fandango]

Thanks tronN00dles, that's definitely something to consider.

 

[Bill.de.Cat]

Running a 4 in. in my 2x4 tent. Going to upgrading to 6 just for the noise abatement.