The rules of venting - venting out of a high level window

Hi all, I’m awaiting my GF+ (due in 2 days) and need some advice in regards to the positioning of the exhaust hose.

Please excuse my naivety on this but will I be ok to vent my exhaust (I’m also adding a 6" external Infinity fan - as recommended by other GF owners) out of a window that is about 5 feet from the ground?

The setups I’ve researched all have mid-level/waist height windows but mine are all higher up and I was a little concerned that although the fan should easily push the air through vertically, I wanted to be ‘surely sure’ as opposed to just doing it and hoping for the best!
Many thanks in advance for your advice.


You should be fine with just the internal fan, especially so with an external booster fan. That is assuming the exhaust run is within the 8’ length of the provided duct or slightly more also depending on how many turns in the duct.
The machine is SO much quieter with an external fan than the 13,000 RPM internal fan. Place the external as close to the building exit as possible, so the run is under negative pressure. That way any leaks will be drawing air in.

You are in for a thrill, enjoy the adventure!


Thanks so much for the advice! I bought an extra 10m hose but my machine is situated almost directly under the window I’ll be venting from so the external fan was going to be positioned just behind the GF unit.
I’m certainly looking forward to being able to hear myself think with the aid of the quieter fan but based on what you said, to truly benefit, perhaps I should vent in a window further away from the machine?
So if I used the full length of the hose supplied, run that to the external fan and then used my extra hose to go from the external fan to the window, that should extract the fumes and smoke proficiently then?

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You should place the fan at the window. Any duct downstream of the fan will be pressurized, not a problem as long as it is airtight.


I’d get a 4"-6" adaptor for the back of your :glowforge: use your 10’ hose (presuming it’s a better quality than the one provided) and don’t stretch it out all the way - put the fan at the end in the window. If you’re just placing the fan in an open window you might end up with blowback. You can either create a window with a hole in it (with whatever material is appropriate for your weather situation), or run the short hose from the fan around the corner of the window.

I’d also get/cut a blast gate for the back of your :glowforge: so you can shut off air getting back in when you’re not actively using it.

There have been some pretty fancy set-ups for high windows (search for basement window to get more)


Excellent! Thanks so much! I’ll see what I can muster!


Interesting you should say that; I was thinking about getting an adaptor as I’d seen others using them too. Thanks for the tips, I’ll do some more research and see how it fits with my setup/studio space.
Much appreciated! :grin:

Small thing, but I think helpful advice, is to think about cross-ventilation bringing clean air into your workspace.

Lately I’ve been GF’ing at night, and closing our craft room door… otherwise my son comes down every 10m telling me I’m being loud (it’s not that loud).
With the door closed, there’s not a lot of air that can come into our craft room, so I find I’m getting air drafting back in the window that I’m suppose to be venting out of.

It’s reasonably well sealed, although I’m going to try to make that better. But last night I tried just opening one of the other windows on the opposite side of the room from the venting window, and this created just enough clean-air input that I got significantly less dirty air coming back in.

So think about pressure, and clean air too, when planning your ventilation.



Thanks for the advice Jestelle - I think I’ve got the clean air situation covered as I’m in a room with great access all round and lots of windows to choose from in terms of positioning - it’s definitely the airflow and pressure that has been the biggest concern so I appreciate the tips! Thanks for taking the time to reach out!


One thing for sure is, you will find out when you hook it up. I have found that people have different tolerances or sensitivities to the odor. I thought I had mine vented well at first but when i had some long sessions cutting material, the smell built up and became bothersome. I added an inline fan to the existing ductwork I already had and it has made a huge difference. Now I run the laser without the internal fan running and the inline fan does the job.


Indeed, it’ll certainly be trial and error regardless but I have already purchased the extra fan so I can turn off the internal one and it’s the one recommended by so many other GF users so I hope it will do a good job.

Appreciate you reaching out!

I’m commenting a little late but thought my experience might help someone. My setup is Glowforge connected to → 4” flexible vent tube that they included connected to → a custom window vent connected to → an additional booster 4” tube fan, connected to → 10’ flexible vent tube. The additional booster 4" fan (110cfm) is to keep air flow vending odors after the printer shuts off. This is super effective at negating most odors indoors because it runs all the time. The additional 10’ of flexible vent tube to push the odors away from my house.

Some miscalculations…
I notice my vent tube between the Glowforge and the window vent expanding a lot when I start a print. I realized this is back pressure from the booster fan not spinning as fast as the fan inside the glowforge. It was also from the additional 10’ of flexible vent tube that the fan needs to now push air thru. This was not allowing the Glowforge to vent as fast as it should and the Glowforge can get dirty a little faster.

I didn’t want to remove the extra booster fan because it is so awesome and keeping odors out of my house, so I ordered and I am awaiting deliver of a much more powerful fan so I can keep my booster fan. I should also be able to keep the extra tubing outside, but I will have to test that.

One feature request to Glowforge would be to add a variable setting to the fan allowing it to run high when printing but run at a lower speed between prints but keep a constant positive air flow out of the unit.


If you have the external fan, why not just turn off the internal fan? One of the main reasons so many of us get external fans is if you turn off the internal the entire operation is SO much quieter.

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If you have an external fan, open up the GF and remove the internal fan and the machine will be quite a bit quieter. Even unpowered, the windmilling built-in exhaust fan makes quite a racket.

*If you’re out of warranty and good with tools and electronics.

Yeah. And that, too. :slight_smile:

Thank you for the advise (and thank you to the rest of you as well. I attached the new high power fan… which is sooooo quiet. I changed out the foil tube for a pvc one, and it seals real nice. I also found the setting in the glow forge app “Glowforge filter attached” which just about shuts off the noisy fan inside. It puts it to a really low state. The system works great and is sooooooo quite now.