Comments on: What is a Pre-filter in an Air Purifier, and Why is it So Important? https://www.airpurifierfirst.com/blog/what-is-a-pre-filter/ Objective, Data-Driven Air Purifier Reviews Fri, 02 Feb 2024 18:19:20 +0000 hourly 1 https://wordpress.org/?v=6.6.2 By: Tolis https://www.airpurifierfirst.com/blog/what-is-a-pre-filter/#comment-13852 Sun, 11 Jun 2023 10:40:42 +0000 https://www.airpurifierfirst.com/?p=5278#comment-13852 Very nice reviews and insights in air filtering technologies. Thank you very much for the effort and continuous updates. I am writing to you to talk about the filters order and their lifespan. My background is chemical engineering. First of all there is a debate about the filters order. The most correct way to place filters is mesh, hepa and then carbon. Why’s that? Activated carbon’s surface area will more drastically decrease with dust than the hepa and gases will not stick. So proper way is to filter all particles and then pass the gases through the carbon. I don’t know if this is counter intuitive. Another more interesting issue is the prefilter. Fine mesh vs more coarse like levoit’s. Fine mesh filters are used primarily to protect equipment, like the fine mesh filters found in cloth dryers in order to protect the motor. Both fine and coarse ones end up having the same performance if equipment protection is not vital. Why? Because the mesh doesn’t do the actual filtration! The mesh is there to build dust layers and these exact layers are the filter which makes it efficient. So another thing is mesh filter cleaning. HEPA will clog faster if the mesh filter is regularly cleaned since it will not filter as efficiently. Actually there are two factors to keep in mind here. Filtration efficiency curve and pressure drop through the filter. As time passes, prefilter’s efficiency curve is rising. Dust layers are accumulated on the filter and particles that would otherwise pass the mesh will not due to impacts with these layers and also electrostatic charges. On the other hand these layers will impact air filtration flow due to increased pressure drop. So the sweet spot of cleaning is not so regular but also not too late. I would like to hear your opinion on the above.

]]> By: Zeby Au https://www.airpurifierfirst.com/blog/what-is-a-pre-filter/#comment-9110 Fri, 19 Nov 2021 01:42:52 +0000 https://www.airpurifierfirst.com/?p=5278#comment-9110 I agree! a video showing how to clean pre filters is also something I would like to see. Hence, this is very informative especially for those who owned one but doesn’t know how to clean it.

]]> By: Milan Antonic https://www.airpurifierfirst.com/blog/what-is-a-pre-filter/#comment-7491 Thu, 18 Mar 2021 21:29:15 +0000 https://www.airpurifierfirst.com/?p=5278#comment-7491 In reply to Sandra Willson.

Thanks.
Will do that, definitely!

]]> By: Sandra Willson https://www.airpurifierfirst.com/blog/what-is-a-pre-filter/#comment-7490 Thu, 18 Mar 2021 20:46:29 +0000 https://www.airpurifierfirst.com/?p=5278#comment-7490 Wow, this is amazing! I sincerely hope you are going to make a video where you clean these pre-filters. 🙂

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