How to reduce Inline fan noise? How to mount grow room fans using elastic bungee cords
Vibration from inline fans is a common complaint for marijuana growers. Exhaust fans mounted directly to walls and ceilings will transfer this vibration, amplifying it. To resolve the problem of too much fan vibration, most growers suspend the fans using elastic bungee cords. Wrap a few bungee cords underneath and attach to hooks that are mounted in the ceiling. The elastic will absorb these vibrations and you will no longer have to deal with a rattling fan even when run at full speed. Some growers will build an insulated box around their fan to completely eliminate motor hum. While effective, its not necessary in most cases if you use the right fan controller to run the motor at a lower speed. That combined with muffling the sound of moving air are the first things you should address. Worry about completely blocking the fan’s noise only if you determine its still needed after insulating the venting and running the fan at a lower speed.
Insulate venting to reduce noisy airflow The noise of rushing air through venting can contribute to a large part of the noise in your grow tent. This noise is more pronounced if you have a powerful fan and lots of angles in your vent run. Try to plan your vent run to be as short and straight as possible. It will increase the efficiency of your setup and allow you to use a less powerful fan. Short and straight venting is also much easier to insulate than long, rambling runs or those with lots of curves. There are several inexpensive options for reducing air flow:
Blankets and duct tape Not pretty, but blankets or towels folded lots of times are great ways for budget-minded growers to address the noise in air vents. Old sleeping bags would work well too. Get creative. This method works well for curved or angled runs. To insulate the venting inside our grow area we didn’t want to risk having insulation fibers ruining our crop, so we used an old blanket wrapped around the venting several times and it works great.
PUT PUMPS ON VIBRATION ABSORBING RUBBER MATS Most growers that use air and water pumps will simply put them on the floor, a shelf or a table. This will amplify the vibrations and transmit a lot of noise
far beyond your grow room. The solution here is rather simple. Take some high-density or rubber foam and place it between the ground and your pumps. If you don’t want to spend money on special sound-proofing material for this purpose, a yoga mat might do the trick. You should never put a pump in an enclosure! Not only can this increase the risk of damaging your pump, but it is also a big fire hazard!
Vent mufflers Air leaving a venting system at high speed will make a “whooshing” sound. To increase stealth, some growers buy a muffler that goes at the end of the run to silence the exiting air. Mufflers start around $50. If you’re overly concerned about noise from exhaust, it’s a pretty reasonable investment. One consideration if you haven’t yet bought your fan: running a 6 or 8 inch fan at lower speeds will mean less exit noise than if you have a 4 inch fan cranking full speed.
USE INSULATED DUCTING Metallic ducting, especially when rigid, is likely to cause vibrations and noise. Ducting that contains fibreglass insulation is a superb compromise, and can vastly reduce the noise created by air movement. This will greatly add to the “stealth factor” of your grow room! Likewise, know that bends and turns in your ducting can increase vibrations. When you plan out your grow room ducting, try to minimise the bends if you can.
Fan speed controllers Speed controllers are great! Especially when you want to get rid of the shattering noises when the fans run at full swing. What it does is, it gives you the liberty of dimming down the fan and have a control on the noise as well. But there are a couple of cases that you need to watch outFirst, if you purchase a wrong grow room fan speed controller that’s not compatible with your fan. You may see the controller in action for a while. But that’ll not operate within the safe range of volts. Result? The premature death of your growroom fan. Second, when you get to slow your fan down, you might not be able to meet the ventilation requirement of the growing system. Also, the temperature may rise high. So, you should either buy additional inline fans and use speed controller on that also. Or you can switch some other methods of noise reduction in this list.
Isolate The Fans with Carboard/Wooden Box
One of the simplest, but working strategy to lower the noise of fans down is to enclose them with a noise-absorbing surface. We’re talking about DIY boxes made of cardboard, wood or any hard and rigid surface that can absorb sound. But many can do a mistake of keeping the boxes in direct contact of the fan. But that’s not just a smart way to do that. We suggest you to suspend DIY fan silencer box from the ceiling and walls. Although this process will cost you a little extra effort, but the result will be fabulous. You can use some bungee cords to suspend the boxes over and none of the vibrations and noises will come out of the box. Also, there is ready-made inline fan silencer box available in stores and Amazon. Can be a good choice if you don’t want to take the hassle of making it all yourself. In together, noise-absorbing boxes suspended from the roof will absorb a decent amount of noise, and prevent vibrations to go through walls. Hanging stuff from the ceiling may come handy, and you may need to install a joist in this regard.