Adding a fan

I have an inline fan that I’ve been thinking about
attaching to my window and then attaching the hose to that so that it would draw the smoke out faster. Is this a good idea or a bad idea??

Unfortunately adding 2 fans in series doesn’t increase the flow as you would expect. It can increase the vacuum pressure but not the cfm flow. Also consider the case openings for the vent air to get into the glowforge and then eventually out the duct were sized for a particular fan flow. So this can also limit the increase in air flow you might expect from multiple or larger fans.

What kind of issue are you seeing that you think more flow is really needed?

@dwardio has a killer vent setup with an in-line fan and others too. Search the forum for “booster fan”, you will find more info than you bargained for. Get a snack and do the reading, you’ll be an expert in no time.


For most people who have done this it’s not about ‘more flow’ but ‘consistent flow’.

  1. The ducting is longer than the specified 8’ with at most two 90 degree bends.
  2. To keep all interior ducting seams at negative pressure to avoid effluent seepage.
  3. To have a fan run after the job is complete to more completely vent out remaining smoke and odors.

I believe the fans displace somewhere in the neighborhood of 200 CFM. My setup with a 4" 190 CFM booster works splendidly.

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Makes sense for those cases. OP didn’t mention extending the hose so I didn’t consider that.

I have a booster fan in line even though my line is quite compressed. To me it’s about constant positive pressure going out the window. That and the dryer vent help make sure that air is always flowing out. It reduces the chance rain will make its way back in, and it keeps air moving out long after the glowforge fan has stopped.

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