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Smith Knowledge Turbo OTG Fan Goggles Review

Smith Knowledge Turbo Fan Goggles

Smith no longer makes the Knowledge Turbo OTG Fan Ski Mask. It’s been replaced by the <a href=”″>Smith Elite Outside the Wire Turbo Mask</a> although the fan is the same.

I’ve owned a pair of Smith Knowledge Turbo OTG Fan Goggles for a couple of years now. They have a built-in battery-powered exhaust fan that prevents fogging, which can a real problem on winter hikes when you need to wear full-face protection in high wind. Available in an OTG size for people with glasses, and well as a regular (non-OTG) version, they’re my go-to hiking goggles when I need to protect my face against frostbite on above-treeline hikes.

Smith Knowledge Turbo OTG Fan Goggles - Front
Smith Knowledge Turbo OTG Fan Goggles – Front

Before I got these Smith Knowledge Turbo Fan Goggles, my goggles and glasses would often fog up on winter hikes, forcing me to turn around before reaching the summit. This happened the first time I tried to climb Mt Washington in winter which was a big disappointment for me since we were so close to the top. There was a period of time after that hike where I carried two pairs of goggles on high-exposure above-treeline hikes, so I’d always have a second pair of goggles available if the first pair fogged up.

Smith Knowledge Turbo Fan Goggles - Fan Housing
Smith Knowledge Turbo Fan Goggles – Fan Housing

Since I switched to these Smith goggles, my fogging issues have disappeared. I’m still careful not to wear my goggles on my forehead before they’re needed, which often causes moisture/sweat buildup and can lead to uncontrollable fogging. I also don’t put my goggles on until they’re really needed, usually because I have to wear them with a full Serius facemask and balaclava, which I’d rather avoid as long as possible since it’s so claustrophobic and cuts down on my peripheral vision.

But once I put my Turbo Fan Goggles on and switch on the fan, they stay clear and unfogged, which is great because I have the added complication of being a glasses wearer. The secret sauce is the tiny exhaust fan built into the center of the goggle, which vents moist air and prevents it from condensing inside of the goggle.

Smith Turbo Fan Goggles - Power Pack
Smith Turbo Fan Goggles – Power Pack

You have the option of turning the fan on or off, or running it on a high or low setting depending on your needs. It just requires two AAA batteries: I recommend you use a Lithium-Ion type like the Energizer Ultimate Lithium which are cold-resistant for winter use and very long-lasting. There’s also a tiny switch on top of the battery housing which locks the power off, so you can’t inadvertently run down the battery when the fan is not in use.

When the fan is in operation, it makes a gentle whirring sound. But the sound is so low, that I can still hear what people around me are saying even though I’m also wearing a full balaclava over my ears.

The weight of the goggles with the battery is just 6.0 ounces. Smith claims that the batteries last for 50 hours before requiring a change, even when the fan is run continuously on a high setting. The goggles also have a dual-lens and are coated with an anti-fogging agent inside for further anti-fogging prevention.

Over the years, I tried other goggles and a variety of liquid and paste coatings to keep my goggles from fogging up on winter hikes above treeline, but none of them have proven to be as reliably fog-free as my Smith Knowledge Turbo Fan OTG Goggles, Highly recommended!

Disclosure: The author purchased this product with his own funds. 

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  1. Michael Brouillette

    With I could a afford a pair for my thru hike I don’t mind a little extra weight if it works to make my hike safer and more fun

    • When are you doing your thru hike? I have to admit carry goggles wasn’t even on my list to bring for a thru hike.

      • I can’t imagine why you would need snow goggles for an AT thru-hike unless you plan on hiking New Hampshire and Maine in winter, in which case a straightjacket would be more apropos. Do your trip planning homework. I don’t think this gear is necessary of you’re doing a typical AT thru from April – September. Good luck with your hike!

  2. Thank you for the excellent review. I was wondering if you- or your readers- have a recommendation for a anti-fog treatment for glasses for less demanding but similarly frustrating situations (for example, hiking in the tropical humidity that we often get in the Northeast US during the summer) that tend to fog the glasses.

  3. Scuba shops sell liquid drops you can smear onto the inside of lenses to prevent fogging.
    The McNett Sea Drops work very well. The difference between brands becomes very noticeable well scuba diving in cold water.

  4. Have you ever tried a tunnel hood instead of the mask/goggles combo?

    • Greg – I like my nose too much. When I need to use goggles, it’s important to have every part of exposed skin covered to prevent frostbite.

      • I guess I could take or leave my nose. :) I had seen that the ADK (in their manual) Winter School suggests tunnel hoods as an acceptable alternative to the mask/goggles combo, especially for glasses-wearers, so I picked up a military surplus one. I also remember Walter C. who was at the BPL meet up a few years ago has written about using his in the Whites in winter. I hear you though–it’s a little daunting to “test-drive!”

  5. I, too, wear goggles over glasses, usually downhill skiing but also on winter hikes. I find that it’s the glasses and not the goggles that fog up. Frustrating as fogging is while hiking, it’s ever more dangerous while skiing. Anyway, Cat Crap and other anti-fogging measures have not worked well for me, and a friend says his prescription goggles even fog, and he’s thinking of going to goggles with a fan. I might, too, but for now I’m using a smaller pair of glasses under the goggles, which leaves more room for air to circulate. It’s been a modest improvement.

    • David, I us a Nikon anti-fogging lens wipe on the inside of my glasses and goggles. It seems to work ok. I usually re-apply it twice on a long days hike. Being able to see is kind of important. I’m going to try the McNett Scuba Anti Fogging stuff that John noted above.,

  6. I’ve been using Smith Turbo Fan Goggles for quite a long time. They are indeed a godsend for those of us with fogging issues

  7. I also use smith fan goggles but with a prescription insert so I don’t need my glasses. I mostly do it for downhill so the minor extra weight isn’t an issue but it is marvelous both to avoid fog and to never have my glasses askew because they are built into the goggles

  8. Any problems with the fan drying out the eyes when you wear the goggles for longer periods?

  9. Tried these goggles on MT. Washington yesterday. They worked great! No fogging what’s at all. Thanks for letting me know about them.

  10. Got these last winter. Have since talked several friends into them as well. Great use for a rechargeable battery so I always know what I’m starting the day with!

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