Extractor fan size vs room size vs the amount of light your plants receive

[BudgetGrower]

Just been thinking how effective the new leds are, They produce less heat, so you can use a smaller extractor fan/filter, when the cooler weather sets in, we are likely to reduce the fan speed, the amount of available CO2 is going to decrease, weed can handle 1000 parts per million (ppm), natural concentration in the atmosphere is around 400 ppm so that short by 600 ppm and a low amount of air exchange in early/mid flower will reduce it, (guessing 300 ppm), the plants could be getting 1000 umol/s and good amount of plant food, is the low amount of CO2 Likely to cause problems?

Is there a minimal airflow per ft2 we should aim for, to keep CO2 in range?
with older lights, you need a larger fan to remove the heat, so it was never a question.

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[tricks4uVA]

Just been thinking how effective the new leds are, They produce less heat, so you can use a smaller extractor fan/filter, when the cooler weather sets in, we are likely to reduce the fan speed, the amount of available CO2 is going to decrease, weed can handle 1000 parts per million (ppm), natural concentration in the atmosphere is around 400 ppm so that short by 600 ppm and a low amount of air exchange in early/mid flower will reduce it, (guessing 300 ppm), the plants could be getting 1000 umol/s and good amount of plant food, is the low amount of CO2 Likely to cause problems?

Is there a minimal airflow per ft2 we should aim for, to keep CO2 in range?
with older lights, you need a larger fan to remove the heat, so it was never a question.

​

 

[Grower1974]

I run $23.00 6" fan. It's runs at 50% speed, and has plenty of air replenishment and control.

Amazon.com

 

[Dudnerd]

If you are really concerned just buy a CO2 monitor. I think you be surprised.

I run a semi sealed room and still have not had to add CO2. And when I go into the room that supplies air to the flower room the CO2 can jump to 1000-1500 easily.

The monitor in the room has never dropped below ambient CO2 levels of 450

 

[Grower1974]

If you are really concerned just buy a CO2 monitor. I think you be surprised.

I run a semi sealed room and still have not had to add CO2. And when I go into the room that supplies air to the flower room the CO2 can jump to 1000-1500 easily.

The monitor in the room has never dropped below ambient CO2 levels of 450

Yep. My home and grow room usually hover between 620-1200ppm without any CO2 added.