Here is a way to help judge if a fan is enough if you are not supplementing co2 you need an air exchange rate of once every 3 min optimum during flower. This is when your plants will be largest but if you can it is always best to be able to control exchange rates so you can adjust temps and humidity to some degree too slow room gets too warm too fast it gets too cold somewhere in the middle both temp and humidity are able to be managed.
Another big factor is Carbon filters which have max and min airflow ratings with a speed controller you can keep filter working effectively longer
yeah going by the stats the fan looks good enough
especially like the 21 db - 24 db sound level!
ive been looking at fans but not in hydro shops
The hydro shops all seem to do the same makes and are prob bumping up the price too!
Seem to have better choice just by going to a traditional electrical supply shop
Plus the Silent 4" is only £55!
Other factors to consider hydro shops tend to sell to people who grow and order what they ask for and buy I am all for saving a buck but make sure you read up on it’s damp location compatiblity. Not too many fans like moving humid air for prolonged times. @Countryboyjvd1971 being an HVAC tech you would know the density calculations far better than I and how it would effect life span of fan. I buy cheap because I know if they are pulling air at 70% RH dust and rust starts to wear on them and they seem to last about half advertised life. It looks like a nice fan and quite is always nice
so working the numbers out (i do like numbers!)
a tent that has a 45 cfm need (which is per 1 minute) then only really needs 15 cfm which would make 45 cubic feet every 3 mins?!?
which would give me the air exchange rate of once every 3 min you advised
So the fan im looking at with its max of 180 m3/h / 105 cfm (or even on its low setting of 140 m3/h / 82 cfm) will be MORE than enough for my tent!
Looks like a speed controller is next on the shopping list!
They do state that they are made “to meet ventilation needs in domestic, commercial and industrial applications” so hopefully theyll have no probs being in my lil attic!
theyve also got a 5 year guarantee so if do break down im covered (as long as i remember to keep the receipt!)
Yeah your right with the humidity affecting life span I try to get Stuff made of plastic not metal myself for that reason but I do use some cheap in line room to room fans as intakes (don’t need to run them that much ) that have metal parts
Hey @Donaldj you inspired me to redo my exhaust ducting getting all materials together now
Picked up a 12" inline fan moves 400 cfm and a wall mounted speed controller will need to do some control wiring but that’s cool I pick up 208 volt model as well to be more efficient will need to run new power over but I’ll only have the one exhaust fan running instead of the 4 I have now
I’ll also put damper collars on each take off on main duct to have a little more volume control and plan on a second damper to control how much I exhaust out of house so I can recover some heat and humidity in the winter months
Lol mine will all be solid ducts when done only have one piece of flex rightnow because my filter is still working hard in my other space. Way quieter and more efficient with reduction in turbulance I may yet go to a 8" fan and 8" duct to my exhaust for cooling efficiency but for now can hardly exhaust without dropping temps too much. But heating space with single light most hours of the day ducting is easy upgrades as needed as you well know. My buddy is a 30yr HVAC tech so if I don’t do something right he harps on me about it and tells me about new products all the time.
The idea is to be able to have entire control of temps humidity while still getting fresh co2 rich air to your ladies with a speed controller you can slow fans right down most fans are adverised max rate of flow. I am running a 435cfm 6" to control a 380 cubic foot space it’s running at about 1/4 speed and passive intake which further reduces exchange rate. Fans are tested for max speed 0 resistance now factor in resistance of filter each bend in ducting size of intake vents you have so many ways to control airflow listing all would be a HVAC techs specialty. Also once every 3 min is a minimum not a maximum but as fan gets faster humidity is harder to keep there is a very fine line and the more you can control the easier it is to grow in
That def helps especially knowing that the 3 min air refresh is a minimum NOT max!
Was worried id be taking the air away too quickly (?!?) but now i see thats not something i need to worry about!
Im also planning on passive intake
Ive got Thermopro in tent at mo to give me an idea of tents natural (lights off) temp n humidity
Gona run the light for 12 hours tomorrow so i know what ive got to deal with when the lights are running!
Then ill be in a better position to work out what im gona need in respect of heaters or cooling!
Theres so much more to this than i first thought!!!
Lol fan speed helps to regulate temps as well as provide fresh air too fast and humidity plummets too slow and temps raise you are doing right thing dry running space makes huge difference once plants are in adjusting things gets rushed and more complicated