The differences with certain fans.

Gregor Eisenhorn

Gregor Eisenhorn

Well-Known Member
Hi everyone!

I'm planning on buying a new fan for my grow box, because even in the winter I have trouble keeping the temps below 86F/30C during the day. The room were I keep my grow box can be exposed to the outside winter air, and while that does do the trick in cooling the box, the temperature in the grow box drops substantially during the night. <13C/55F.
I have come to believe that if I upgrade my existing fan from 120m3/h or 70CFM to let's say 280m3/h or 160cfm, I will be able to maintain better temperature levels during the day. (I'm only aiming for 25C/77F and for the night temps to be at 70F.

Unfortunately a cool tube is not an option, because my grow box 58x49x160c, (22x19x62inches) is just too small.

Now, finally my question arises. Why do some fans cost substantially more than others, despite the m3/h // cfm rating to be the exact same.
I do understand that the materials used to make the fans are different, so that definitely impacts the cost of each fan, but could it be because the more expensive one is more efficient (even if the air exchange rating is the same)?

I just don't see the point of paying so much more money for a fan that de facto will do the same job but just looks cooler. The fan that costs lower is not made of paper mind you, and is still a quality fan.

Thank you for your help, I want to choose the best fan I can afford now and truth be told, I would like to pay more if it meant the air exchange will be better.

Could I be missing something?
 
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brimck325

Well-Known Member
do some research, check reviews.....some fans are obnoxiously loud if thats a worry for u. sorry couldn't be more helpful.
 
Gregor Eisenhorn

Gregor Eisenhorn

Well-Known Member
So the difference in the wattage is that the cheaper fan uses 20W and the more expensive 40W (which for a difference in 20m3/h is a little weird) but that doesn't really mean anything to me apart from the monthly cost in electrical bills.
 
Crab Pot

Crab Pot

Well-Known Member
I have three 6" exhaust fans. The first cheapo fan ($100.00) that it moves air just fine but has a one year warranty and is LOUD... I looked for a good internet deal and found two 6" Vortex S-series ($119.99/fan) fans which have ten year warranties and are super quiet. It really is amazing the difference in quality.
 
Gregor Eisenhorn

Gregor Eisenhorn

Well-Known Member
Thanks Crab, that's good input. So generally speaking it's the quality and sound that is mostly affected.

Do your fans have then same air exchange rate?

I mean technically the higher the wattage the more actual power is used, which is then an impact on the efficiancy. But still if both fans have the same cfm rating but different wattage then I don't get it.
 
Crab Pot

Crab Pot

Well-Known Member
They have similar air exchange rates. I really like using fan speed controllers to control air flow.

I wouldn't worry too much about which fan uses the most electricity, the difference on the electric bill is so minor. I would compare air flow, price and warranties.

You might want to check out the Vortex S-series fans. Perhaps a little more expensive but it's tough to beat a ten year warranty and their really is a substantial difference in materials and quality. What fans are you looking at?
 
Gregor Eisenhorn

Gregor Eisenhorn

Well-Known Member
Not much an offer in Poland unfortunately, but I was looking at those three fans I posted here on this thread.

The cheapest one, at 20W exchanges 260m3/h,
the middle range fan at 40W exchanges 280m3/h and has a substantial ncrease in cost,
the most expensive one, albeit just alittle more expensive then the middle one, exchanges a whopping 420m3/h and works at 60W.

So I'm really baffaled whether I should choose the cheapest one since it has basically the same exchange rate or the more expensive ones that work at a higher wattage. (although I just calculated that the difference in impact on the electrical bill is minimal, so I don't worry about that. I just want to choos ea good fan, although if there's not much of a difference between the cheapest and middle one, then I would prefer to save a bit of dosh and spend that on for example a good pH pen.
 
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Stevie51

Active Member
Gregor Eisenhorn said:
Now, finally my question arises. Why do some fans cost substantially more than others, despite the m3/h // cfm rating to be the exact same.
Click to expand...
You also made it clear that there was also a substantial difference in the wattage. Wattage is also a measurement of the amount of work a motor is capable of doing. The performance of a fan is defined as the amount of airflow in cfm at a given static pressure. Static pressure resistance caused by components in the ventilation path reduces the amount of airflow a fan give out. With the lower wattage fan the amount of airflow will rapidly decrease as opposed to a using the higher wattage fan under the same static pressure conditions. However given that you have a small grow box I'm hesitant to suggest which fan would be better for your circumstances. I been told that having too much of an airflow can be bad on the plants too.
 
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Crab Pot

Crab Pot

Well-Known Member
I wouldn't go with the cheapest, it's only a duct fan, not really an exhaust fan. I don't think you would be happy with that decision. Between the two most expensive their doesn't seem to be that much difference in price but there is a big difference in the amount of airflow. I would go with the most expensive and put a speed controller on it. You won't have to worry about the heat any longer. It would be great to see you get your temps down to the mid 70's. Good luck with your decision!
 
Gregor Eisenhorn

Gregor Eisenhorn

Well-Known Member
Stevie51 said:
You also made it clear that there was also a substantial difference in the wattage. Wattage is also a measurement of the amount of work a motor is capable of doing. The performance of a fan is defined as the amount of airflow in cfm at a given static pressure. Static pressure resistance caused by components in the ventilation path reduces the amount of airflow a fan give out. With the lower wattage fan the amount of airflow will rapidly decrease as opposed to a using the higher wattage fan under the same static pressure conditions. However given that you have a small grow box I'm hesitance to suggest which fan would be better for your circumstances. I been told that having too much of an airflow can be bad on the plants too.
Click to expand...
Thanks Stevie for clearing that out for me. I admit that my knowledge on wattage and electricity is appaling, but now I understand the differences. I'm thinking more about the most powerful one, I might one day move to a new cabinet/tent so I would prefer to buy something that works and use it for the years to come. Once again thanks for the help, I'll sleep on the decision tonight.
 
Gregor Eisenhorn

Gregor Eisenhorn

Well-Known Member
Crab Pot said:
I wouldn't go with the cheapest, it's only a duct fan, not really an exhaust fan. I don't think you would be happy with that decision. Between the two most expensive their doesn't seem to be that much difference in price but there is a big difference in the amount of airflow. I would go with the most expensive and put a speed controller on it. You won't have to worry about the heat any longer. It would be great to see you get your temps down to the mid 70's. Good luck with your decision!
Click to expand...
You know, something at the back of my head was encouraging me to not buy the cheapest one. It's pointless saving money on things you shouldn't. You're right about the two other fans, I'm also thinking about getting the most powerful one and just turning things down a notch with a speed controller. Thanks for the help Crab, I'll sleep on it tonight!
 
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