Duct booster fans are very versatile to cannabis cultivation. They give small-space gardeners peace of mind in knowing that all odors are moved in a controlled flow straight to the exhaust fan.
If you are going to be using a passive intake system using an inline duct booster fan and an exhaust, read on to understand what you’re working with.
We’ll be showing you how to hook up a duct booster fan while also highlighting key insight to keep in mind regarding the rest of your setup.
Hooking Up a Duct Booster Fan to Ductwork
If you have extensive ductwork leading away from your exhaust you can install a duct booster fan to guarantee that the warm air is carried to an outlet at an optimal rate. Buy a duct booster fan that matches the diameter of your ductwork; 6 inches is the most commonly found measure. Metal fixtures will screw on while fiber polymers affix with tape. Some duct booster fans drop into vents; others connect as a part of the ductwork itself.
Once fitted, your duct booster will pull hot air, directing it to an outlet. They, therefore, help control humidity within your growing area and are best used on a dedicated exhaust fan timer.
Using a Duct Booster Fans as a Primary Inlet
Duct booster fans can be used as the primary inlet for small-space indoor growing. They’re ideal for growing in grow tents and perfect for a grow op concealed in a closet or small storeroom. Duct boosters are especially useful as the primary means of cooling for 400W to 600W lighting.
When rigging a duct booster fan as an inlet, make sure that your intake hole is significantly larger than your exhaust, and it should also be on the opposite side. Most grow tents are already built for this.
How to Use a Duct Booster Fan as an Exhaust
Four to six-inch duct booster fans are ideal as exhaust fans for small-space gardening. If your cubic volume is low, perhaps around 150 cubic feet or less, duct boosters make for a worthy consideration as exhaust fans. In most cases, their mid-range power lets you get away without needing a variable speed controller. Set in place a thermostat and the duct booster will blow away the heat.
Don’t Use Duct Boosters With Carbon Filters
Duct booster fans are simply not powerful enough under pressure to run a carbon filter or carbon scrubber. Even if your duct booster fan states a rating capable of handling the filter, it's highly unlikely that the CFM will match up as soon as the air encounters resistance. For example, a 550 CFM duct booster doesn’t push out anywhere as much constant power as a basic, tiny 4” inline fan carrying a low 200 CFM rating.
Avoiding Pressure Reduction Problems
Owning a powerful duct fan which is improperly installed causes high-pressure reduction This results in the pressure dissipating and the volume of air moved far lower than your fan is rated at. If you want to minimize dissipation within your system then follow this checklist to ensure that you don’t suffer a pressure drop.
- Ensure that the inlet has a distance which is greater than 75% of its diameter
- Ensure that the inlet duct is at least the same length as its diameter
- Free the inlet from any obstacles and clean it thoroughly of dust and debris
- Measure the cross-section of the inlet’s duct and make sure that it is between 112% greater and 92% less than the fan inlet’s cross-section itself
- Ensure that the straight length measures at least three times the diameter of the duct after a duct booster fan is placed
- Use 45-degree bends only
- Position exhaust fans exactly opposite to the inlet
Duct Booster Fans – Ever Versatile
The optimal use for duct booster fans is to move air, not generate pressure. They are especially useful for very long ducts either leading to your inlet or from your outlet. It is often difficult to find a vertical exit which is close enough for your exhaust outlet to reach easily. In these cases, you can use a duct booster fan to make sure that you’ve got enough CFM to flush the air away.
Never try to use a duct booster as the primary ventilation in any other than a very small space. As soon as your CFM requirements exceed 100 CFM, an inline fan or active intake is a far better idea.