Indoor grow rooms come with a lot of advantages, but with these come a few drawbacks. Keeping your house from smelling like an intense hotbox all the time will be hard. You can always try an air purifier or odour-neutraliser, but those won’t keep the dank smell completely out.

Carbon filters will be the best option for you. They provide an air extraction solution that not only keeps the smell out of your house, but doesn’t send it elsewhere. This prevents the threat of unhappy neighbours. If you live in an area where you can’t be too careful about the discretion of your operation, carbon filters are the way to go.


It might seem weird how one device can simply make a smell extinct. But when you get chemistry involved, it becomes clearer. The carbon used is all active. This means it has been treated with oxygen to give it a highly porous surface. Air will pass easily through it, but unwanted smells and fragrances will bind to the carbon. These filters will need to be replaced, but will last you a long time. Be sure to inform yourself better on this depending on the scale of your operation.

Carbon filters are huge, heavy duty tubes with loads of carbon inside. You connect them to your exhaust fan, forcing all the extracted air from your grow room to pass through the filter. If you have a small setup, a granular carbon filter will be enough. In case you run a larger operation, you’ll be needing a block filter. To understand better which choice to make, you should check for the CFM - cubic feet per minute (or cubic metres per minute/litres per second) value of your fans. You have to ensure that your exhaust fans can handle the filter. Purchase a filter with an equal or lower CFM value than that of your fan. The CFM can be easily converted to metric values with simple equations.

Carbon Filter Cannabis Indoor


Once you get the adequate filter, if you don’t set up everything correctly, you’ll be throwing all your money away. It doesn’t matter how expensive your setup is if there is still going to be an air leak. You have to guarantee that all the air that’s being pulled from your room is going through the carbon filter.

The most practical way to do this is to include the filter as part of your exhaust system. Either place it before or after your fan. The air will either be pulled or pushed through the filter, neutralising all odours as a result. The most efficient solution is to place the filter as the first passage of the air when it's being pulled. The fan should be the last element before the tubing that leads outside. Make sure everything is well-sealed. As we mentioned, it’s the “make or break” of the whole process.


Purchasing a carbon filter can cost over €100. If you’re not ready to spend this much money, there is a DIY solution. This one will be ⅕ of the price and can be just as effective, if built properly. Let’s get into it.

You’ll be needing a few materials. These are all super cheap and can be found both at your local store and online shops. The products we’ll be listing are not exclusive. This means that you can probably achieve the same, if not better results, by using other, similar materials you have available to you.

You’ll need:

  • Roll of aluminium screen or chicken wire 
  • PVC cleanout cap & PVC adaptor (both should have an equal diameter) 
  • Dryer vent hose to fit into adaptor 
  • Roll of duct tape 
  • Roll of quilt batting
  • Laundry basket (preferably with lid)
  • Activated carbon

Carbon Filter Materials


Create a tube out of your chicken wire or aluminium screen. Plug the PVC cleanout cap into one of the ends. Duct tape these two elements together securely.

Then, place the upright tube in your laundry basket so that the unplugged side faces up, and trim the edges so both elements share the same height. Next, plug the PVC adaptor into the open end of the wire/screen tube and duct tape them together.

Remove the screen tube from the basket. You’ll be covering it with quilt batting, and lining your basket with it as well. Fold your batting in two, so that the thickness of the material doubles, and use this to cover the outside of your screen tube. Make sure the quilt overlaps, and then duct tape everything in place.

Now, do the exact same process, but to the inside of the laundry basket. Use duct tape as necessary to keep the batting in place. Place the screen tube inside the basket with the cleanout cap side facing down. Once this is all set up, fill the margin between the tube and basket with the activated carbon. 26mm of the carbon layer will be enough. If you feel like you’re using too much of this, your gap might be too wide.

With this done, cover the exposed carbon on the top end with more batting. Remember to also cut a hole through your basket’s lid so that the PVC adaptor is sticking out, and attach the dryer hose to this. Then, attach the opposite end with the cleanout cap to an air blower output.

And that’s it! You’re ready to roll. This will last you about the same time as a store-bought version of the product. Now that you have the system set up, just replace the carbon once every couple of years and you can truly feel safe about stopping odour propagation from your indoor plantation.

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