TerraBloom ECMF-200, Quiet 8" Inline Duct Fan with 0-100% Variable Speed Controller, Air Tight Metal Casing, Energy Efficient EC Motor. HVAC, Growing and Exhaust Applications Blower for Large Spaces

I originally ordered a less expensive fan but it did not allow me to vary the speed much and was noisy. This TerraBloom fan is very quiet and comes with two speed controls. One allows continuous control from 0 to the max rpm. The second one allows 6 stepped rpms. I didn't use either of the included controls and opted for the TerraBloom Programmable Thermostat Speed Controller with Temperature Probe for an additional $45.99. It is definitely worth the extra money. You can see my review of it on Amazon. You can save a few bucks if you order this fan with the programmable controller. I didn't see that option.

I bought this to use as a power fan unit to pull the exhaust from my desktop laser engraver/cutter ("K40") and force the exhaust thru a series of filters (pre-filter, carbon filters, 2x HEPA filters). The air force this fan is capable of generating is insane. I actually bought this one after comparing the other models CFM specs. This one says it has an airflow of up to 569 CFM. I have a leaf blower that is 700 CFM and the force behind that is also insane, so I wanted a fan unit that could get me as close to that as possible while also being self contained. This unit does exactly that. It is also built extremely impressively well. No rough/sharp edges at all. This is as professional as it gets. And it does exactly what I need it to with regards to pulling air thru the filters. My only issue is with regards to my design in how I implemented the fan, in that I go from the laser's exhaust at 4" diameter, thru duct vent tubing, then to a 4"-to-3" reducer into a homemade filter box, out to a 3"-to-4" inverted reducer, to a 4"-6" inverted reducer, to a 6"-to-8" inverted reducer. The reason for all of the required reducers is because there's no easy way to connect a 4" diameter to an 8" diameter. It's uncommon. So the stark bump down in diameter drastically effects the pressurization internally. The fan wants to pull the 569 CFM thru 8" diamter tubing, but I'm only giving it a narrow 3" plus a load in the form of the filters. Needless to say, I'm really pushing this fan to a limit. But it's excelling at it.

I used this to boost the HVAC to a distant room that was poorly regulated. I removed the base and mounted it between two new end plates in a 8x12 rectangular duct. Tied the power to the fan control thermostat circuit via relay so any time the HVAC was on the aux blower would be also. I really like the speed control, allowed me to get just the right bonus flow to the distant room. It comes with a digital and a potentiometer (rotary) type of controller. I used the digital one. Both retain the setting between power cycles. I have it set to 3 (of 8) and can barely hear the blower, even when right under it.It has about a ~15 foot control cable and 6 foot power cord. it also comes with a short breakout control cable if you want to make your own controller, with a tachometer signal available, which I didn't need or use.My only concern is the 140F max temperature rating of this unit, but I don't think my heater will violate it.

I actually normally use it on a setting of 1 out of 10. At higher numbers, the flow is tremendous (more than I need). It does get noisier as you go up the scale. At "1" it's just perfect , quiet and strong.

I’ve been using this duct fan as a booster for my home’s HVAC system for three years now. I only use it in the summertime, but it has worked perfectly. Very quiet, especially at low speeds.

This is my 3rd Terrabloom blower. The first one was not a brushless, and it didn't last long in a humid environment. My second one, which is a brushless EC, still works being outside(under a roof) running year round. This blower powers my air purifier, which I require due to MCS, and it never stops running unless I have a power outage or am changing the carbon. It's run for me regardless of temperature or humidity.Note about the rheostat: I would not tinker with it too much. It's a set it and leave it deal. I tried to use it to turn on and off daily, and it did not last long that way. It started running max at most attenutations and was difficult to turn off, so I ended up having to disconnect it.

Installed this fan in-line to my daughter's bedroom vent air duct since the air flow was too weak. I took two stars off because the fan speed is really not adjustable at the low end. It only starts turning when speed control pot is at 20% of the scale, and is already too powerful for my daughter at this starting point. It is way too inconvenient now to disassemble the unit, so our only workaround is to partially close the air duct flow flap.

I am an HVAC biz owner that used the 8” fan to feed two 6” branch ducts (with an 8” intake). I turned my customer’s unusable bonus room above their garage to the coldest room in the house when it was 95 degrees outside. That was at a 75% setting. Might have to turn it down a touch! With the manual control it will always come back on if there is a power outage or you can hook it into a timer or relay control. Fan was nice and quiet and seems very well designed. I cannot account for longevity as I installed it and left. Time will tell.Fan starts out slow and Ramps up - a nice feature. I was testing it on my kitchen counter when it arrived to see how it performed. When it first came on I thought “there is no way this is 700 cfm....then it ramped up and nearly blew everything off my counter and started skating across the granite. Yeah, that’ll do!