6 ms·

Interesting, I didn't know this about ISS. I've fought a tiring battle to get my CO2 levels below 500ppm consistently, and it's night and day compared to the 80

Interesting, I didn't know this about ISS. I've fought a tiring battle to get my CO2 levels below 500ppm consistently, and it's night and day compared to the 800-1200ppm I used to measure. Can't even imagine what 5000ppm is like!

nolroz 5y ago
Have you felt benefits from getting your levels lower? What steps did you take? Do you have a sensor you recommend?
- tailspin2019 5y ago
  Also interested in the answer to this!
- dbsmith83 5y ago
  You can just open a window and circulate air in the home to lower CO2 levels. I use a uHoo sensor https://getuhoo.com/ https://getuhoo.com/
  - vkat 5y ago
    How has the uHoo sensor worked for you?
    - dbsmith83 5y ago
      So, I bought one and it was great, but then randomly the CO2 sensor seemed to stop working after a few weeks. It stayed at the exact same ppm level without changing for a while. I sent an email to customer support and they shipped me a new one for free, and didn't even require me to send back the old one. Haven't had any issues since. I'm pretty happy with it.
- sparker72678 5y ago
  Not the OP, but I've been using a model by Awair for a while now (looks like they've released a new product that's a bit more expensive since I got mine). I work in a very small office shed, and if I leave the door and window closed tight it will quickly get over 2000 ppm (45-60 min). At that point I'm typically feeling more tired, and a bit foggy. By keeping the window cracked I can keep the readings down in the 800-1100 range, and I feel much better.
  - Aspos 5y ago
    You may want to look into wall mounted recuperators. They provide decent ventilation while not loosing too much heat.
  - BackBlast 5y ago
    Get some plants?
    - Aspos 5y ago
      Office plants can't absorb 1kg of CO2 per day
- xyzzy_plugh 5y ago
  Yes. I feel much more alert, but oddly I have a much harder time falling asleep. I've since started regular low-dose melatonin which helps a lot. In particular I find I am much less groggy in the mornings, and stepping outside doesn't feel like a breath of fresh air. The changes I made are not options for most. I have an industrial rooftop HVAC unit for a space about 5x larger than my home. The fans run continually and there is no fresh air exchange per se but part of the return duct runs through the attic which is not air-tight, more of an open cavity. I change the air filter every 3 months and keep the returns clean by vacuuming regularly. I try not to close doors to encourage circulation, and my bedroom door had an vent to the hall above it -- not sound or light proof, but doesn't restrict airflow. The key that I've found is airflow. A closed room and a bunch of fans won't help you, but circulating the air of your entire home will make a big difference. It's important that your home breathes. An airtight home is actually very unhealthy, though heating/cooling is more efficient. Lastly, cooking is the worst offender for poor air quality. Having a stove-top exhaust hood that actually filters and vents outside is so important. Cooking without exhaust or fresh air can easily bring the kitchen and surrounding areas near 1000ppm in under an hour. I keep my exhaust vent on more often than not and it makes a big difference. Negative air pressure is good: air is pulled in from outside.
CoastalCoder 5y ago
I remember discussing this a while back on HN, and one issue was that consumer-grade CO2 meters aren't reliably calibated. So just curious for my own designs, how certain are you about those ppm numbers you listed?
- OJFord 5y ago
  Not GP (nor a metrologist) but 50% reduction is surely the important thing anyway, in a home setting, not the absolute figures? I don't think the curve could be much off, since they work by counting particles, so if it's reading high at 800ppm then it should be reading just as high at 500ppm right?
  - CoastalCoder 5y ago
    I agree that presumably less CO2 is better than more. I'm thinking that the specific CO2 concentrations matter if one wants to relate the readings to various research on human mental performance.
- eightysixfour 5y ago
  I have tested quite a few against calibrated commercial hardware at this point and they’re not as poorly calibrated for CO2 as you would think. The particulate counts and VOCs are usually only good for comparative measurements from the same device in my experience, and even then the drift is quite large.
  - JohnJamesRambo 5y ago
    All my CO2 meters read about the same as the one in my grow room that controls the CO2. I don’t think that is a big problem.
  - mdp2021 5y ago
    I am desperately looking for one for the car, do you have anything to suggest? Also, I am finding products that seem to require an Android or iOS device to work: no. They must be independent. If they had a webserver, nice idea, but all connections should be unrequired and switchable to off.
Raz2 5y ago
My CO2 sensor self calibrates to show 400ppm as outdoor / minimal concentration. I was very upset to find out that it's not correct. In the last 5 years outdoor concentration rose from ~400 to ~420. Guess my kids won't be able to maintain < 500ppm.

nolroz 5y ago

Have you felt benefits from getting your levels lower? What steps did you take? Do you have a sensor you recommend?

tailspin2019 5y ago
Also interested in the answer to this!
dbsmith83 5y ago
You can just open a window and circulate air in the home to lower CO2 levels. I use a uHoo sensor https://getuhoo.com/ https://getuhoo.com/
- vkat 5y ago
  How has the uHoo sensor worked for you?
  - dbsmith83 5y ago
    So, I bought one and it was great, but then randomly the CO2 sensor seemed to stop working after a few weeks. It stayed at the exact same ppm level without changing for a while. I sent an email to customer support and they shipped me a new one for free, and didn't even require me to send back the old one. Haven't had any issues since. I'm pretty happy with it.
sparker72678 5y ago
Not the OP, but I've been using a model by Awair for a while now (looks like they've released a new product that's a bit more expensive since I got mine). I work in a very small office shed, and if I leave the door and window closed tight it will quickly get over 2000 ppm (45-60 min). At that point I'm typically feeling more tired, and a bit foggy. By keeping the window cracked I can keep the readings down in the 800-1100 range, and I feel much better.
- Aspos 5y ago
  You may want to look into wall mounted recuperators. They provide decent ventilation while not loosing too much heat.
- BackBlast 5y ago
  Get some plants?
  - Aspos 5y ago
    Office plants can't absorb 1kg of CO2 per day
xyzzy_plugh 5y ago
Yes. I feel much more alert, but oddly I have a much harder time falling asleep. I've since started regular low-dose melatonin which helps a lot. In particular I find I am much less groggy in the mornings, and stepping outside doesn't feel like a breath of fresh air. The changes I made are not options for most. I have an industrial rooftop HVAC unit for a space about 5x larger than my home. The fans run continually and there is no fresh air exchange per se but part of the return duct runs through the attic which is not air-tight, more of an open cavity. I change the air filter every 3 months and keep the returns clean by vacuuming regularly. I try not to close doors to encourage circulation, and my bedroom door had an vent to the hall above it -- not sound or light proof, but doesn't restrict airflow. The key that I've found is airflow. A closed room and a bunch of fans won't help you, but circulating the air of your entire home will make a big difference. It's important that your home breathes. An airtight home is actually very unhealthy, though heating/cooling is more efficient. Lastly, cooking is the worst offender for poor air quality. Having a stove-top exhaust hood that actually filters and vents outside is so important. Cooking without exhaust or fresh air can easily bring the kitchen and surrounding areas near 1000ppm in under an hour. I keep my exhaust vent on more often than not and it makes a big difference. Negative air pressure is good: air is pulled in from outside.

CoastalCoder 5y ago

I remember discussing this a while back on HN, and one issue was that consumer-grade CO2 meters aren't reliably calibated. So just curious for my own designs, how certain are you about those ppm numbers you listed?

OJFord 5y ago
Not GP (nor a metrologist) but 50% reduction is surely the important thing anyway, in a home setting, not the absolute figures? I don't think the curve could be much off, since they work by counting particles, so if it's reading high at 800ppm then it should be reading just as high at 500ppm right?
- CoastalCoder 5y ago
  I agree that presumably less CO2 is better than more. I'm thinking that the specific CO2 concentrations matter if one wants to relate the readings to various research on human mental performance.
eightysixfour 5y ago
I have tested quite a few against calibrated commercial hardware at this point and they’re not as poorly calibrated for CO2 as you would think. The particulate counts and VOCs are usually only good for comparative measurements from the same device in my experience, and even then the drift is quite large.
- JohnJamesRambo 5y ago
  All my CO2 meters read about the same as the one in my grow room that controls the CO2. I don’t think that is a big problem.
- mdp2021 5y ago
  I am desperately looking for one for the car, do you have anything to suggest? Also, I am finding products that seem to require an Android or iOS device to work: no. They must be independent. If they had a webserver, nice idea, but all connections should be unrequired and switchable to off.

Raz2 5y ago

My CO2 sensor self calibrates to show 400ppm as outdoor / minimal concentration. I was very upset to find out that it's not correct. In the last 5 years outdoor concentration rose from ~400 to ~420. Guess my kids won't be able to maintain < 500ppm.