#corsirosenthalbox

I keep reading about Corsi–Rosenthal boxes as DIY air purifiers that outperform all commercially available air purifiers. You literally only duct-tape four HVAC filters together and slap any regular PC fan onto them. US-Americans recommend the brand #Filtrete for MERV-rated HVAC filters, but in Europe that brand costs at least twice or thrice as much as in the USA. Are there any equivalent affordable HVAC filters in Europe with a MERV rating of 8 or 13? Or do I simply have to swallow the additional cost because HVAC filters aren't as ubiquitous in Europe as they are in North America? #DIY #CorsiRosenthalBox #CorsiRosenthal #HVAC #HEPA #MERV #AirQuality #AirPurifier #AirFilter

@boiga@kolektiva.social @steter@mastodon.stevesworld.co

How and When to Change the Filters in Your #CorsiRosenthalBox

by WCAHS September 18, 2023

"Corsi-Rosenthal Boxes provide excellent filtration of indoor air, especially for particles containing the virus that causes COVID-19 and wildfire smoke. After assembling and using your Corsi-Rosenthal Box, you may be wondering when and how to change the filters. When to change the filters

"The filters used in Corsi-Rosenthal Boxes generally have a lifespan between 1,000 to 4,000 hours of actual use time on the mid-flow setting. The range varies based on the size of the filter (one inch or two inches), frequency of use, and differences in the indoor environment in which it is being used. For example, it is best to change the filters nearer to 1,000 hours for a dusty indoor setting with carpeting and/or indoor pets. Changing the filters at approximately 4,000 hours is recommended for a relatively clean indoor environment without carpet.

"This filter change recommendation means that you could use a Corsi-Rosenthal Box on the mid-flow setting in an uncarpeted office, for example, for eight hours a day, five days per week and the filters would last for about 25 months. In contrast, a Corsi-Rosenthal Box used for six hours a day, five days a week in a breakroom adjacent to a workshop with people coming and going would need to have the filters changed after about eight months.

"Many people underestimate the life of the filter because they compare it to a filter in an HVAC system or assume that it needs to be changed because it looks dirty. The timeframe for changing the filters in a Corsi-Rosenthal Box is different from changing filters for an HVAC system because the filter width and the air speeds through the filters are different between an HVAC system and a Corsi-Rosenthal Box. In a Corsi-Rosenthal Box, discoloration means that the filter is working and does not necessarily mean that it is time to change the filter.

How to change the filters

- Switch the system off for at least six hours before removing the filters to limit exposure to newly deposited viruses.
- Take the box outside or to a large open area inside. Removing the filters may release a small amount of particles.
- It is recommended to wear a KN95 mask or better while changing the filters.
- Working one by one, cut each filter away from the fan and gently place it in a trash bag. Be careful to not shake or drop the filter as sudden movement can disperse dust and particles into the air. 

• Follow this step again for all filters in your Corsi-Rosenthal Box. Change all filters the same day. Never use a combination of new and used filters in your Corsi-Rosenthal Box. - Tie the bag tight and put it in the garbage. Wash your hands thoroughly with soap and water. - Using new filters, you can now reassemble your Corsi-Rosenthal Box.

Note: If the cardboard base is damaged or worn, you will need to replace the cardboard when replacing the filters in order to properly rebuild your Corsi-Rosenthal Box for maximum efficiency.

Summary

- The filters in Corsi-Rosenthal Boxes have a lifespan of 1,000 to 4,000 hours.
- Many people underestimate the lifespan of a filter.
 - Although risk of exposure from discarding the filters is very low, precautions, such as wearing a KN95 mask or better, are recommended when changing filters.
- All filters should be changed at the same time."

Source: aghealth.ucdavis.edu/news/how-and-when-change-filters-your-corsi-rosenthal-box

#CRBox #AirQuality #DIYAirFilters #WildfireSmoke #AQI #HEPAFilters #CorsiRosenthalBox #AirCleaners

RE: https://social.ridetrans.it/@Andres4NY/116931466428900883 Tagging this thread for #SolarPunkSunday... Discussions about building one's own #CorsiRosenthalBox from folks who have built them. These ones use computer fans, which is a lot quieter than the box fans recommended in the original instructions by Corsi. #DIY #CRBoxes #AirCleaners

Seeing North Americans post about fan-filter-boxes built with box fans and HVAC filters and am reminded of someone back on Twitter (I think it was Amanda Hu) turning their entire home into a fan-filter-box by putting fans into windows on one side of the house and then putting the filters in windows on the other side of the house. Remember: you want the air to be blowing outward and being pulled inwards through the filters. #FanFilterBox #CorsiRosenthalBox #CRBox #IndoorAirQuality

I clearly need a long-term solution for maintaining my respiratory health when there's wildfire smoke. What are people doing? Anyone recommend specific respirators? (I don't particularly want to rely long term on being able to get a very specific type of filter if that's possible.) Is the Corsi Rosenthal box the best thing for my house? Is there a permanent version I won't hate looking at? (I have basic Levoit purifiers.) #wildfires #MaskUp #corsirosenthalbox

Today, I was asked about effective air cleaners, because wildfires have already begun to flare in North America. Extensive global testing has found that a DIY #CorsiRosenthalBox will outperform almost every commercial HEPA unit while costing less to run. For the US & Canada, the best source of filters to build one is Costco: Filtrete 1900, 2200, or 2500 models with at least one 20-inch dimension. These units also help mitigate allergens and infectious aerosols like #Covid and Influenza. 1/3

Scientists Tested a DIY Air Cleaner – And It Beat Expensive Filters By American Chemical Society, March 24, 2025 Excerpt: "As Corsi highlights during his presentation, he and his colleagues recently tested the durability and performance of #CRBoxes by installing units in four locations across the UC Davis campus. They ran them for 2,500 hours — the equivalent of two K-12 school years. "The CR Box filters performed as well or better than comparable #HEPAFilters. The #DIY system was also more effective at clearing particles 1-3 micrometers in diameter than particles 0.35-1 micrometers. For a sense of scale, typical smoke particles are smaller than 1 micrometer, whereas dust and pollen are 0.5-3 micrometers. "Although HEPA filters are more efficient at removing particles in a single pass than the HVAC filters used in the DIY system, Corsi explains, much more air passes through the CR Boxes, leading to more particles being removed from the air. Although the CR Boxes’ effectiveness diminished over time, they still performed better than new and more expensive HEPA air filters for the larger particle size and performed competitively with HEPA for smaller particles over the extended study period." Read more: https://scitechdaily.com/scientists-tested-a-diy-air-cleaner-and-it-beat-expensive-filters/ #DIYAirCleaner #CorsiRosenthalBox #CorsiRosenthalBox #AirCleaners #AirFilters #DIY #WildfireSmoke