Carbon Filters: Should I Use One in My Grow Room?

So you’ve completed setting up your grow room, and you’ve started cultivating some plants. You don’t notice it at first, but eventually you notice your growing area has a rather telling odor.

Whether it’s the strong smell of your plants or a little bit of funk from humidity, chances are you’ll want to keep the aromas of your grow room to yourself. If you want to keep your operation discreet, or you simply want to keep the smells from your growing area out of your house, you should consider using a carbon filter in your grow room.

What Are Carbon Filters?

Like most air filters, a carbon filter is designed to purify the air that comes into it and exhaust fresh air into the room. These metal cylinders are filled with carbon media and connect to a high output fan in order to remove odors and particles from the air in your grow room.

Carbon filters are available in a variety of sizes depending on the size of your grow room and the amount of filtration you’re looking for. When set up properly, all the air from your grow room will go through the filter, and the odors in your grow room will disappear.

How Carbon Filters Work

It’s actually quite simple: Carbon filters work by trapping unwanted smells (odor particles) and dust particles in order to allow fresh, odor-free air to filter through the tube.

There are a variety of materials carbon filters use, but most — including Yield Lab carbon filters — use charcoal. It’s a porous material and useful for many things — from getting rid of certain gases in the air to being used as lining for face masks.

Active carbon has a massive surface area with hundreds of pores. These pores can trap molecules from the air through a process known as adsorption. This process allows molecules like dust, dirt, and odor molecules to stick to the carbon, preventing them from traveling freely back into the air.

Of course, air doesn’t just float into the carbon to be filtered. You force the odorous molecules from your grow room to stick to the active carbon within your carbon filter with an exhaust fan. The fan pulls all the air in your grow room and pushes it through the filter, effectively keeping dust and odor molecules from escaping and spreading odors outside your grow room or grow tent system.

Using a Carbon Filter in Your Growing Area

When it’s time to start using a carbon filter in your growing area, there are some important steps you need to keep in mind.

Find the Right Size

All carbon filters are not made equal. Depending on the size of your growing area and the cubic feet per minute (CFM) value of your exhaust fans, there are different-sized carbon air filters that will be right for you.

In order to determine the CFM value, you will need to follow these steps:

• Measure the height, width, and length of your grow room or grow tent.
• Multiply these numbers in order to calculate the cubic footage of the space you’ll be using.
• Multiply this number by the exchange rate (the number of times you want the air to be completely exchanged each hour). To have a constant flow of fresh air, you’ll want to multiply by 60, which is once per minute.
• Your CFM is this number divided by 60.

The best way to figure out which size carbon grow room filter you should use is to make sure that your filter's CFM value is either equal to or lower than the CFM value of your grow room and your exhaust fan.

For example, say you have a 5ft x 5ft x 8ft grow tent:

• Multiply 5x5x8. You get 200, which is the cubic feet of your growing space.
• Multiply the cubic feet (200) by the number of exchanges per hour (60), which gives you 12000.
• Divide that number (12000) by the minutes of exchange in an hour (60) for a total of 200 CFM.
• Take the 200 CFM you have and look for a filter that meets or exceeds that CFM.

Rule of thumb: It’s always better to go over your CFM requirement than under. If you get a smaller filter than you’ll need, you’ll use up the carbon quickly.

Set Up Your Filter

Once you know which size filter you need, you then need to make sure that you set it up properly. In order for you to make the most of your carbon air filter, you need to ensure that it is filtering all of the air that is in your grow room.

This means you need to connect it to a grow room fan and connect ducting to it, then seal it properly using duct clamps.

Place the fan and filter above or near your plants. Next, position the fan so it pulls air from your grow room and exhausts it into the filter. This setup will make sure that all of the molecules in the air will pass through your carbon filter before any air leaves your grow room.

Maintain Your Carbon Filter

When all of the pores, or adsorption sites, in the carbon are full, your carbon filter will no longer be able to trap new molecules. You can maintain your carbon filter by making sure you clean it regularly — typically once a month.

In order to clean your filter, you should take the filter out of your grow room, then shake out any trapped dust and debris.

Note: Contrary to popular belief, using water and soap to clean charcoal in a filter can actually have an adverse effect. Remember that charcoal breaks down, and with the aid of water, you can speed up that erosion.

Eventually your carbon filter will get to a point where it is unable to trap as many molecules as it used to. Depending on how much work it’s forced to do, carbon air filters should be changed every one to one-and-a-half years. That said, if you start to notice a strong odor even after you clean the filter at home, chances are it’s time for a swap.

Should You Use a Carbon Filter in Your Growing Area?

The answer to that question is a resounding yes!

Carbon filters are the best option for keeping the smell from your growing area out of your house and away from your neighbors. More importantly, they’re the best way to make sure even the freshest air is used by your plants to grow.

It’s worth noting that there are other short term solutions that you can use, like air purifiers or neutralizing sprays and powders. That said, these tools do not completely remove the smell from your growing operation, and they will not completely eradicate any dust particles that come from your grow room. Even worse, a lot of times, sprays and gels that attempt to scrub the air actually harm the terpenes and flavor cells of a plant.

The best way to guarantee that your grow room is safely odor-free and keep smells from escaping your growing area, is to use a carbon filter.

You can start by finding the right filter for your grow room by clicking here!