I am a professor at a research university with a research interest in indoor air quality (IAQ). The CO2 meter is a must for IAQ studies, as CO2 measurements can be used to: indicate CO2 pollution level by comparing the US EPA guideline value; calculate air exchange rates to indicate the ventilation condition; and calculate fresh air supply to ensure occupants’ comforts.
I previously used a Hobo CO2 meter coupled with a Hobo data logger, but this combination requires complicated connections and is costly. A year ago, I searched CO2 meters on the market when I started a new project. In most IAQ field studies, an ideal CO2 meter should fulfill the following requirements:
- Can measure CO2 concentration continuously, and have the ability to log the measurements for a long period.
- Can measure temperature and relative humidity simultaneously.
- Has a wide concentration range but still keep high resolution, precision and accuracy. The ideal range is 0-10,000 ppm.
- Can be easily connected to computer to download and manage the logs.
- Low cost, ideally below $500 USD each.
- An LCD screen is sometimes a negative as it will attract people to watch closely and thus the readings will increase due to breath.
- Minimum buttons on the meters in case people touch it for curiosity.
After a thorough search, I found the K-33 ELG CO2 data logger on www.CO2meter.com had all the features I was looking for. The price was especially attractive at $350 and could be even lower if you buy more. Some extra upsides:
- It is totally quiet when it is logging
- Downloading data is fast
- The meter can be set up easily using the software
The only shortcoming I found is the USB to Serial Custom Cable. The end connecting the meter could be easy to break, and must be handled with care. I found a small flat head screw driver helped.
This meter has many applications in my IAQ studies. As an IAQ professional, I highly recommend this product.