Re: Air purifier
From: Sharon Villines (
Date: Mon, 18 Oct 2021 12:19:01 -0700 (PDT)
> On Oct 18, 2021, at 2:13 PM, Sandy Thomson <sandykthomson [at]> 
> wrote:
> Has anyone purchased an air purifier for their common house dining room to 
> help with the spread of covid?   Which one did you buy and how much was it.  
> We need something to service about 2000 sq feet. 

We haven’t but I did recently find this and recommend we buy one — don’t have 
it yet so haven’t tested it. 

Consumer Lab is an independent testing lab that has recommended CO2 monitors to 
measure room ventilation to reduce Covid Spread. It doesn’t filter but checks 
the air to see who good the ventilation is.

I think this would be a good check of ventilation in the CH and could also be 
borrowed for people to check their units. Their top pick which is $99. It is 
small like a room thermometer and easily moved. 

Room Carbon Dioxide Monitors: A Good Way to Assess Room Ventilation and Reduce 
COVID Spread?

Carbon dioxide (CO2) monitors have become a strategy to reduce COVID-19 spread 
by assessing the quality of air ventilation in rooms. Some places, including 
New York City and the U.K., have distributed carbon dioxide monitors to schools 
as part of pandemic precautions to help detect when ventilation needs 
improvement. These devices cost about $100 to $300 and can be reliable, 
although there are important limitations to their use.

Why use carbon dioxide monitors?
Carbon dioxide is exhaled during breathing and accumulates in rooms with 
inadequate ventilation. Consequently, carbon dioxide levels can be an indicator 
of how well indoor air is circulating and a proxy for how well airborne 
coronavirus is eliminated. In general, a well-ventilated indoor space should 
have a carbon dioxide level of less than 1,000 ppm, although many experts, 
including the CDC, consider 800 ppm a more suitable limit during a pandemic.

Good choices among CO2 monitors
The following are examples of devices that meet the above specifications:

        • Top Pick: IAQ Max CO2 Monitor & Data Logger ($99)

This device is our Top Pick due to its features and low cost. The main display 
screen of this monitor shows the current CO2 level, while a secondary display 
charts readings every 10 minutes over the last hour. The device can also be set 
up to log data every 1, 5, 10, 30 or 60 minutes for up to 30 days, and the data 
can be downloaded to a computer to review. The battery lasts for only 3 hours, 
but the device can be plugged in for longer use, and it can be recharged when 
necessary (it takes about 2 to 3 hours to become fully charged). The unit 
weighs 0.46 pounds, and its dimensions are 5.7" x 3.0" x 3.8". The device can 
be purchased from

There is more information on the site — too long to summarize accurately.

Sharon Villines
Takoma Village Cohousing, Washington DC

  • Air purifier Sandy Thomson, October 18 2021
    • Re: Air purifier Paul Harrington, October 18 2021
    • Re: Air purifier Sharon Villines, October 18 2021

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