Why would I want to use one of these?

Air filters help remove viruses, bacteria, and allergens from the air. Hotel rooms usually have poor ventilation and, especially when crowded, can be prime locations for transmitting respiratory diseases. Air filters can help you and your friends not get sick. They can also help keep those pesky fur fibers out of your lungs, too!

Does this cost anything?

No, borrowing a filter from us is completely free! We want to make clean air available to any fur that wants it.

How long can I keep it for?

At least overnight, and longer if demand allows. Please check in with us every day you have the filter, as someone else may be waiting to borrow it.

Can I borrow more than one at a time?

Yes. Let us know why you’re interested – for example, a crowded room party is a good reason to use multiple air filters.

Will this prevent me from getting sick?

An air filter will NOT eliminate the chance of infection, but it will lower it. We’ve seen a case where a Covid-positive fur did not infect their con roommate after multiple days of sharing a room – they did not mask in the room, but they did run an air filter. We CANNOT guarantee this will always be the outcome, but using an air filter can improve your chances.

Can I use this instead of wearing a mask?

An air filter does NOT provide clean air as effectively as a well-fitting, high-quality N95 mask, particularly in close-contact situations, and should NOT be considered a replacement for one. Multiple layers of protection (e.g. masks and filters and tests) are always the best strategy. However, if you cannot wear a mask, using an air filter will give you better chances of avoiding infection than not using one.

Where should I place the filter?

Place it where it won’t be knocked over or have anything spilled on it – so away from walkways and away from anywhere food and drink are being consumed. Keep at least 6 inches of clearance to the front and back of the filter.

What fan speed should I run it at?

The lowest fan speed of 1 is sufficient, but if you’re not bothered by the noise, you can turn it higher for higher filtration.

Oh no! I spilled liquid on or damaged the filter!

Accidents happen, but please let us know right away so that we can make sure the next borrower is getting a functional filter. Taking pictures promptly will help us evaluate the damage.

Can I put stickers on the filter?

Yes! Put stickers on the cardboard shroud at the front of the filter only, making sure not to block the flow of air. SFW only, please!

Can I use the filter to dry my fursuit?

Yes, but please keep your fursuit in the front (where the fan is blowing out) and keep it at a distance of at least 6 inches. Avoid touching the filter with sweaty fursuits. Don’t brush fur out into the back of the filter.

Can I take silly pictures with the filter?

Yes! We’d love to see pictures of our filters in action and keeping your party safer. Please let us know if we can use them promotionally.

What exactly are these and how did you make them?

Corsi-Rosenthal boxes are homemade air purifiers made out of box fans and furnace filters. They’ve been shown to outperform most commercial air purifiers, despite costing much less. There are many designs of CR boxes; we’re using one designed by Devabhaktuni Srikrishna called SAFE, and you can follow his instructions at Patient Knowhow to make your own. We used Lasko 20″ box fans, 20×20×4 MERV 13 HVAC filters from Tex Air Filters, duct tape, and 3/4″ Velcro tape. Each assembled unit measures 20″×20″×8″ and weighs 7.5 lb. Everything except the HVAC filters was purchased from Home Depot and Walmart. The materials cost to make 6 filters was $359.98, plus taxes and shipping.

Why did you choose this design?

We wanted a design that had high CADR and that wouldn’t take up too much space in a car or in a hotel room. We also wanted something that was cheap and easy to put together and take apart. Since our primary audience is events and parties, we didn’t prioritize getting it super quiet (which can be achieved with PC fan designs). If you’re making your own to use at home, come chat with us about what design will suit your needs best.

What’s the CADR? How many ACH do you get?

We don’t currently have a way to measure (we’re thinking about getting one in the future), but it’s probably in the neighborhood of 300 cfm per unit on the lowest fan speed. ACH depends on the size of the room it’s in, but in a typical hotel room, 300 cfm can get you 6 ACH.

What about the gaps between the fan and the filter?

These small gaps have negligible effect on performance, and we prefer a clean and modular setup over having to seal everything with duct tape. Since the filter has low pressure drop and high surface area, far more air is being pulled through the filter than through the gap.

Can I make my own fleet to lend out?

Yes! One hyena can only go to so many cons – we’d love to have more of these around the world so we can help more people. Get in touch!