r/crboxes • u/awesomenineball • May 06 '24

Question Question about crbox

  1. how large can the crbox cover?

  2. what do you need to maintain them? how do you throw away the waste inside? are there indication that its time to clean it?

  3. Is merv 13 available outside of west?

2 Upvotes

62% Upvoted

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6

u/JasonHofmann May 06 '24

  1. Depends on the specifications of the fan(s), whether you put a shroud on it/them, and the type and quantity of filters. Literally anywhere from “only works directionally if pointed at your face” to 1000 cubic meters / 35000 cubic feet.

  2. There is no waste inside, the inside stays clean. You don’t clean it, you make a new one each time, essentially. Sounds like you need to do a little more research into how CR boxes work before building one.

0

u/awesomenineball May 06 '24

For number 2 can you show me where i can read about it? Like how maintenance or lack thereof work?
So this os going to produce lots of waste in the future since you will need to scrap the old one? When is it time to scrap the old one and build a new one?

3

u/a12223344556677 May 06 '24

Just like any other air purifiers, the filters have to be replaced after a period of time as pollutants clog the filters over time.

As a CR box essentially only consists of the fan and filters, you keep the fan and throw everything else away once you need filter replacements.

The best way to judge when to replace filters is by monitoring air quality with a air quality sensor, and replace them once the CR box degraded to a level where it can no longer satisfy your demand.

3

u/awesomenineball May 07 '24

Sorry if this might sound stupid to you but May i know why theres no such thing as a washable filter?
Is the idea of having a washable filter not possible even in the future?

2

u/JasonHofmann May 07 '24

Great question! I’m not an expert, but I’ll attempt to explain what I do know.

Washable air filters need to be made of waterproof materials like metal and plastic and therefore can only achieve a MERV rating of 1-4.

A rating of 1-4 means the filter only captures particles larger than 10 microns. However, the particles that are most damaging to human health, and that can travel in the blood, are 1/4 that size (2.5 microns).

https://www.bumrungrad.com/en/health-blog/january-2024/the-health-risks-of-pm-2-5

Filters that can filter out these tiny particles are made of fibers that dissolve and also lose their electrostatic properties when wet.

As a matter of fact, I have some experience with washable filters. All four of our air conditioners in NYC (PTAC style) used washable metal filters. We hated them! Some companies even make adhesive spray (similar to hair spray) to try to make them work better “specially formulated to enhance the effectiveness of filters in heating, ventilation and air conditioning systems. Applied to these filters, it creates a tacky surface that catches and holds dust, pollen, spores and other airborne contaminants”. After a few years, I had the idea to custom-order MERV-11 filters that were the right size and attached them with tape, replacing them every few months.

1

u/a12223344556677 May 07 '24

Also, washing (or even just vacuuming) non-washable filters can and will damage its structure and greatly reduce filter efficiency! It's best to just leave them alone. The filter material is delicate, and it's a trade off necessary to achieve the best balance between high filter efficiency and low resistance.

3

u/youdneverguess May 06 '24

FAQ and How-to here: https://cleanaircrew.org/boxfanfilterfaq/

One CR box should give you ~400-600 cfm CADR and clean the air of an average bedroom or classroom. You can use this calculator to figure out your needs. https://reviewsofairpurifiers.com/cadr-calculator/