Opinions on mask fans. Worthwhile? Noisy gimmick?

[Altec]

Bunch of my team mates ran homemade fan setups. A couple sub-30mm fans ziptied to the vents with a small battery pack and switch. Worked better than any off the shelf option. Not for cooling, simply to keep fogging at bay in the muggy MD summers.

[lew]

My fan in my JT Spectra works well, but that noise is a problem. Out here, where the humidity is low, it is better to move your head often and introduce airflow. Back in the Midwest, I never had a problem with fogging on a thermal lens.

[JonM]

Let me just say that when I got my ExFog setup, I tested it by wearing it and my mask during a 20 minute workout on my elliptical. By the end, my foam was completely soaked in sweat, yet my glasses and lens were completely fog free. I even turned it off a couple times to make them fog and turning it back on again cleared them both almost instantly.

[nerdcore]

I don't use fans now, but back when I wore glasses under the mask, it was necessary. My glasses always fogged but my mask lenses never did. I never used them to keep cool.

I only used homemade ones similar to those Fanz kits.

[Jaan]

Sorry for resurrecting an old post, but this came up in a Google search on the first page;
I used to wear eyeglasses and struggled with fogging like everyone else. I got lazik and gave my homemade kits away but before I did that I had posted a couple of extensive DIY posts on the old MCB.
If you have a JT shroud, one of my tutorials used a JT shroud but modified.
The key to having the fans quit and efficient is to have them run as slowly as effective, and mount them above the mask. Some of the fan kits I see for sale on eBay the fans are mounted directly to the mask. This will cause a lot of noise (at least the guy doesn't use 25mm fans handing off the edge anymore 😁) The second part of that equation is that I used a pulse width modulator to be able to adjust the fan speed as needed. The one I made was just made up of transistors but I've looked recently and I've seen quite a few pre made circuits on AliExpress (new tutorial might be up soon).
For the JT shroud kit I used a Dremel tool to open it up a little and I was able to get two 25mm fans inside the shroud with a pulse width modulator and 4AA batteries. On a low setting the fans moved a huge amount of air and the 4 AA batteries ran the kit for 10 hours before I stopped counting. It was so quiet I often forgot to turn them off.
The second kit I made for a Profiler mask. I used two 20mm fans but I used simple plastic sheeting to raise them above the mask a little which lowered the sound significantly. You still need to make a shroud out of sheeting so the air is pulled through the mask (just like a car and the radiator shroud). I used the same kind of pulse width modulator but this time since the fans drew less power, I used 4 AAA batteries. I think I got 6 hours of continuous run time on the fastest setting.
See if you can dig up the old post with pictures. My nephew is starting to play paintball and he wears glasses, so I'm going to make him a set of fans. I will make a tutorial and post on MCB when I do.