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Hall of Fame of Corsi/Rosenthal Boxes – or ideas for your own box!

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    These are pictures of each tweet of someone who has built a CR Box, and all are linked to the actual tweet. This is by design so that you can click on the tweet, and ask any questions you might have directly of them. Such as, “What is the name of that contact paper?”

    This first CR Box is very, very well done. It has the shroud, which with the Utilitech fan will result in a 47% improvement of performance. If the fan is a Lasko fan, it would be a 38% performance increase.

    It is on casters for ease of movement, and is the 5 filter version, which is why it needs to be raised. The bottom is a filter as well. Bravo!

    This next fan is the actual Tweet so that you can click on it and play.

    It’s the 4 filter version, so the bottom is not a filter, but it is absolutely brilliantly done, looking like a record player.
    The middle of the “record” is actually a downloadable picture.


    Next up, we have a fantastic 5 filter CR Box with a Utilitech Fan, raised slightly to allow the air to come in the bottom. Great usage of colored duct tape – the possibilities are endless!

    You’ll notice his filters are from Tex-Air Filters, which is owned by Jim Rosenthal – the R part of the Corsi-Rosenthal Box. Thanks to Jim’s industry knowledge, he was able to build Dr. Corsi’s concept, and he also innovated the usage of the shroud.

    This next CR Box is a very nicely done 3 Filter build. It was one of the first to use contact paper over the cardboard, and is just tres chic.

    This next one is an excellent example of the 5 Filter build. And the spacing below it is to really maximize the amount of air flow. Well done!

    It should be noted that the fan optimally would be flipped the opposite way, pointing to the ceiling. This accomplices 2 things. First, it is a safety feature. It’s entirely possible that infectious respiratory aerosols have been dried out and drifted to the floor. If the fan aimed down, it could lift them back up.

    Secondly, by pointing up, you are helping the air move around more efficiently. Dr. Poppendieck talks about this here.

    This next 4 Filter build has a very cool use of clear packing tape, not often seen.

    And brings up a topic – be very careful buying filters from Amazon. FilterBuy, these filters, had some of their filters knocked-off and sold on Amazon. Always check with an authentic distributor.

    Your health is no place to decide to save a couple of bucks.

    This very nicely done fan is set up in a classroom. It’s also an interesting one, where the shroud is set in the bottom of the fan, instead of the top. For optimal performance, putting the shroud on top is recommended.

    Also – if you have a standard classroom, at least 2 CR Boxes are recommended – especially in a windowless room.

    Beautifully done, and very nice use of white duct tape!

    Amazing creativity! Class Mascot? Should be the Pandemic Mascot!


    ThIs one shows off the creativity and fun the whole family can have. “Sharky McSharkerson”!

    This next filter is a 1 Filter build, using the box that the fan came in a as an offset.

    Per David Elfstrom
    , this is a “1” filter with box offset to maximize exposed filter area instead of having it flat against the fan housing and corners”

    Very slick use of the duct tape to give it a great, almost commercial appearance!

    Here is a great little sideways-aimed 4 Filter Build. It would be better aimed up at the ceiling, but having a sideways-aimed CR Box is way better than having no CR Box!

    The staging here with the books is just brilliant!

    Great use of duct tape to make the shrouds below!

    You might think this is a double-decker CR Box. It is not, just staged on top of each other.

    And that brings up a great point. Usually, it’s better to have a couple of CR Boxes
    spread around a room.

    This next CR Box is a classic 4 Filter Build with duct tape shroud. It’s an example of fun for the whole family! Kids really get into building these!!

    And if you are a teacher, you might think – hey – Science Project! And we got you!

    Fantastic usage of 2 CR Boxes in her classroom (and really good placement) – and a great DO NOT TOUCH sign.

    Should you be worried about kids touching these? Not really – and here’s why.

    Talk about a clean looking CR Box! Good looking!

    This box is demonstrating great spacing from walls. Sometimes you have to put them right next to walls for safety reasons, but spaced away is better!

    This next box has a very chill masculine vibe. Guys have lungs, too!

    This next CR Box – wow! The staging!

    Using 20X25X 1 filters (often HomeDepot and Lowes have MERV13 1900 20X25X1’s at almost the same price as the smaller 20X20X1 filters)!

    More bang for your buck!

    I highly recommend you click on the pic – complete documentation of performance specs!

    Dr. Corsi, shown below in the red nose. (IN THE LEFT PICTURE). Is famous for bringing red clown noses.

    This next build is great because it shows the journey to clean lungs.

    Fantastic use of colors, and such a great family project!!!

    Huge projects like these ARE possible!!!!
    If you need help persuading your principal or superintendent to go forward with this, we’ve got a letter prepared for you!

    Perfection in one picture – that’s what this is!

    Chic, cheeky, and Corsi/Rosenthal Boxes. Say goodbye to CoVid – (remember those masks!)

    Great collection of 3 and 4 filter boxes! And – make sure you tag David if you do big groups of them!

    Love to see the giving spirit!! There’s a newspaper article there – click away!

    Great use of the box it came in to form the bottom!

    Showing the shaka – right back at you, sir! Love the spirit, the 5 Filter Build – and innovative handle to move it around! Mahalo!

    A CR Box is also handy for when you cook bacon! Very practical! Think about the summer with fire season!


    Beautiful blue and yellow CR Boxes all ready to go! 18 of them. About $1800 in cost. But delivering about $16,200 in clean air. Priceless!

    Incredibly beautiful box. Inspirational to tell the truth!

    Don’t forget – we have a letter AND tactics to help you in your quest to protect your loved ones’ lungs!

    A rare international build from Switzerland. These are the filters you want if in Switzerland!

    One CR Box above, there was an inspirational box. This one is inspirational for the location. Every church needs air cleaners!!!

    People have been asking if this will help a windowless classroom? YES! If you have no opening windows, then you especially need these!

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