70 months ago
I have the option to either install 1 240 mm fan or 2 120mm fans, what should I go with? What are the pros and cons of both large and small fans.
1 large fan can move the same amount of air as a smaller fan at a lower rpm, making it quieter and more efficient. However, 2 smaller fans combined might negate that benefit, at the cost of more noise and losing 1 fan header
I was generally thinking one 240mm fan is limited to location ie. side panel were as 2 120mm fans can go front/back intake/exhaust.
True, but front panels normally have quite a few options. I went with 2 140mm fans instead of a 200mm fan for the front intake of mine
Area a circle A = Pi times r squared
Pi (3.142) x Radius ((70mm)140mm fan) Squared
3 x 120mm = 33933.6 mm² = 0.36526 ft²
1 x 140mm = 15395.8 mm² = 0.16572 ft²
3 x 140mm = 46187.4 mm² = 0.49716 ft²
1 x 200mm = 31420.0 mm² = 0.33820 ft²
If a 200 mm fan is spinning at the same speed as a 140 mm fan the tips of the blades are moving much faster . This is part of the reason why a larger fan doesn't have to spin so fast to move more air . A bonus of that is that it then makes less noise. So one big fan instead of 2 small ones.
Maybe but if they are the only fans 2 would be better imo.
For less noise and good cooling (or exhaust), one big fan.
For a lot more cooling, 2 120mm fans are better due to the larger amounts of options available in that size... You can get many fans that are each over 80cfm, but the big fans are only made in a couple models and are around 70-80cfm.so 2 high performance 120mm fans are a lot louder but can move more air combined.