I was lucky to get my hands on 5 proper co2 sensors from university, while I was teaching and working. So plenty of test places.
What I found:
-Just a couple of hours in a office, without ventilation spikes the co2 enough to make everyone dizzy and tired by the end of the day. Keeping eye on the meter and ventilating properly, increased everyones productivity and people werent so tired by the end of the day.
- Classrooms, with 20-30 people are as bad. co2 rises really fast and makes people dizzy. Most often ventilation is too low, as a cost saving measure.
-Closing bedroom door, sleeping alone made bedroom as bad by the morning than classroom or office.
-Main culprit seems to be our perfection with insulating and making rooms airtight. I do live in a cold climate, so having open vents or windows is not common half the year. It seems it has not been such a big issue before plastic windows or in older houses. I think it is getting worse with every new building.
As someone who has built my fair share of houses and worked on many more over the last 25 years, I have to agree that our ability to seal air better than ever is causing problems, especially if you don't have forced air heating and cooling running all the time. People just completely ignore or haven't ever thought about room ventilation, positive or negative room pressures, and where and how to ventilate to the outside. In older houses there was always air leaks, small, but they let the house breath, especially if you had a central fireplace and your house was at negative pressure. I have seen many people purposefully over seal their house in ill conceived ways, to try and improve insulation, but end up causing ventilation problems with mold being especially common. Materials and vents that should let air pass through are commonly replaced with impermeable plastics and sealing tapes, many times in conjunction with a misunderstanding in expansion and contraction joints that have small gaps.
> As someone who has built my fair share of houses and worked on many more over the last 25 years, I have to agree that our ability to seal air better than ever is causing problems, especially if you don't have forced air heating and cooling running all the time. People just completely ignore or haven't ever thought about room ventilation, positive or negative room pressures, and where and how to ventilate to the outside. In older houses there was always air leaks, small, but they let the house breath, especially if you had a central fireplace and your house was at negative pressure. I have seen many people purposefully over seal their house in ill conceived ways, to try and improve insulation, but end up causing ventilation problems with mold being especially common. Materials and vents that should let air pass through are commonly replaced with impermeable plastics and sealing tapes, many times in conjunction with a misunderstanding in expansion and contraction joints that have small gaps.
Sorry, but this is just wrong and is the type of "accepted wisdom" that holds back construction, particularly here in the UK.
Repeat: ventilation and permeability are different things.
Yes, permeability can achieve some ventilation but it comes at the cost of:
1) Not being reliable; it is dependent on pressure deltas around the dwelling.
2) Being potentially deleterious to the fabric of the building where escaping warm air cools and water condenses on surfaces in the fabric.
3) Being wasteful of energy.
The solution is to separate the two:
1) Seal the fabric totally, bearing in mind vapour permeability. The seal should be on the warm side of the insulation.
2) Install a ventilation system which provides reliable fresh air and, ideally, exchanges the heat leaving the building with the fresh air coming in.
We can no longer rely on folksy wisdom. Let's engineer our houses.
Apparently certain residential building codes have air-freshness provisions:
I recently added A/C cooling to a previously heat-only house, and I took the opportunity to ask the company to explain some quirks in the existing system, like how the ventilation fan in the laundry room is on the same breaker as the central heating, and had a hidden timer attached to it.
The house was built (early 1990s) with a particularly powerful vent fan in the laundry room which was on (regardless of the wall switch) a certain number of hours a day, and the forced-air system had an air intake outside the house which mixed with the return air before hitting the filter.
This was all sized such that all the air in the house would be replaced about once every 24 hours, according to WA state's VIAQ ("Ventilation and Indoor Air Quality") code.
That's all been superseded by the International Mechanical Code and International Residential Code.
I have a 100+yr old house, no vents. Old style radiator. Doors have large gaps underneath them, the holes on the floor that the radiator pipes travel through have gaps that you can feel the draft. It's annoying, but the house really does breath and is noticeable comfortable for me unlike houses with forced heat that are sealed well.
And I recently remember hearing forced air is bad for air quality inside! Did I hear wrong or is there something more to the story like “forced air brings in outside air, so if your outside air is bad you’ll have trouble”?
South Africans are (at least historically) quite different in this respect. Everyone is cold in the winter due to complete disregard for insulation (at least, when compared to Europe). People also don't get layering. The comments about construction do hold mostly. In the warmer areas of the country usually you are cold in the winters for only a couple hours per day.
When we go overseas we tend to open all the windows. Maybe this is because we are not used to long winters.
My grandparents were experts at opening select windows in their houses to create drafts in the pre-aircon age.
There is a meme: "If a guy invites you to a braai at his home at 3am, it really is a braai."
Mold is not a ventilation problem, but rather a moisture control problem. Keep the humidity down (especially with whole house dehumidifiers), and eliminate condensation points (by eliminating thermal bridging), and it goes away.
While the above video, which is from the really good channel by Matt Risinger, is a good introduction, I recommend you also check out the building science stuff put out by Joseph Lstiburek for a more science-y explanation:
My house is absolutely frigid during the winter, and I got quote for resealing it. He told me that afterwards I am either going to have to leave my windows open (no thanks!) or live with mold.
I've heard that you can install vents, but can't find useful info.
My grandparents had a chute vent, and it somehow became a breeding ground for flies and all sorts of ichies. Not sure why.
And short vents sound to me like an always open wondow, which just brings in the cold.
I want the insulation, the circulation, the breathability and the warmth. Is there any way to have it all?
My friend studied Interior Architectural Design, one of his professors there started one lecture a year by getting the CO2 sensors, placing them around the lecture hall, showing the readings at the start of the lecture, closing the doors and then after the hour long lecture showing the readings.
During the lecture he mentioned the figures for CO2 concentration that led to symptoms, e.g. dizziness, sleepiness etc.
The reading at the end of the lecture showed that it was over the recommended limit, and well beyond the threshold that causes people to get sleepy and lose concentration. (I believe it was less than 400ppm at the start and thousands ppm afterwards?)
A simple demonstration using an older building crammed full of students in a closed space, but it was apparently quite impactful in showing the students how there are a lot of features of interior design architecture that aren't really addressed and are only coming to the fore recently.
This now makes me wonder if there is another dimension to the “people who get in early or stay late are more productive than those who work traditional hours.”
I’ve attributed this to “fewer people, fewer distractions.” However, with a CO2 component... hmm.
Well, there is another project idea. Arduino with a CO2 sensor and plotting a running total. Or not displaying and instead have a “I feel productive” dial that would allow for correlation to the recorded data.
>there are a lot of features of interior design architecture that aren't really addressed
Nearly every standard rectangular building should be in actuality built with the energy efficient building design in mind, but we don't... out of simple mental oversight and in the increased cost in construction.
Literally, we could save 20% to 30% in energy costs with every building with possibly only 10% to 15% increase in cost of construction, but we simply don't because we have no congregate valuation of resource consumption, only individual guilt.
Maybe this is why I would feel sleepy during lectures. I always thought it was because I was mismanaging my sleep or the teacher was boring (it was probably a combination of the three).
+1 here. I worked at an IoT startup with a lot of gas sensors. When we tested the CO2 sensor, we immediately noticed a correlation between early-afternoon sleepiness and high CO2 levels. Opening the door to the outside world lowered levels and within 5 minutes we felt more awake. It changed how I work: I still like to be warm and cozy, but now I'll bundle up and endure changing the air rather than seal every door and window as I used to.
I feel like most of these experiments don't control for air temperature. I feel like cold air has a much more rejuvenating effect than just lowering CO2 levels. Not that they don't matter, but it's not like you'll instantly feel better.
This is wildly conjectural, but assuming the "CO2 is causing widespread cognitive problems" hypothesis is true, I wonder if there are whole colleges whose student bodies are getting slightly worse grades because of this. There are a couple of small colleges in my area that are regionally famous for their stuffy buildings.
The worst would be a small leak of CO (not CO2) , even in very small quantities, daily miligrams of CO coming from a leaky(small leak) Gas burning heating system. This will most probably get students scores down, among other extremmely bad health effects.
Bigger CO leaks are extremely dangerous, many people lost their lives because of heating systems.
If you can, change to Oil Flow system with burner outside the house and far and aislated from humans. Or, if you can, electrical system. CO from gas is Really Very dangerous.
(using the word "very" is against Mark Twain's advice[1], and using the word "really" is against my own advice, but there are exceptions, here above was one)
1:
“Substitute "damn" every time you're inclined to write "very" ; your editor will delete it and the writing will be just as it should be.”
Mark Twain
2- "delete all instances of "really" in you text, and your writing will be better"
ImmerseintheImmensity, Also unknown as InfimousInfinity, Also unknown as ParadoxParalax
Curious if you have a link to what sensors you had? Think this is cool and i've been on/off looking for co2/o2 sensors greater than recreational precision
Can’t speak for OP but I’ve been using the IQAir Air Visual Pro and can support everything they’ve said. I try to keep CO2 around 400-500 in my office and home but it spikes surprisingly fast with even one person breathing in a medium sized room.
It can integrate with HomeBridge and has a good API and unlike a lot of IOT stuff it’s well supported and stable.
They were too expencive to buy recreationally, at least for me. Evikon, small company that does science instruments. Sorry, cant find the model anymore, I think it was discontinued.
I do belive now though that even having recreational level sensor will give you at least understanding overall co2 levels and this something we should look into more.
I founs a paper using the same sensors that measured co2 in schools. In all cases, at certain times the measurement was higher than norm. occassionally over 2000. I can now understand much better kids getting sleepy and unable to concentrate in classroom.
We're on track to reach 1000ppm by the end of the century, if levels continue to rise at their present (accelerating) rate. This is about the threshold where cognitive effects become reliably detectable. However, such levels also bring climate change on such an apocalyptic scale (4.5+ degree temperature rise) that industrial activity could well wind down as society collapses.
Indoor air co2 only lowers due to outdoor filtration. So, higher outdoor co2 will make us reach higher indoor levels faster. A change of outdoor air to 500 from 400 ppm, for example, means there's 16% less difference with indoor air at 1000 ppm.
All/most modern houses (10-15 years old) have central ventilation systems here. This allows for great insulation while also having great ventilation. The central system sucks out warm air from bathroom/kitchen and uses it to warm up incoming air from the outside.
My previous employer had excellent air quality and I often stated this to others as one of the things I liked about working there. A lot of people look at you kind of funny if you say that but it really was remarkable, and I really felt a difference when working in that building compared to when I went to school and a lot of other places where you stay inside for a prolonged time. I felt much less tired there than most other places!
It seems it has not been such a big issue before plastic windows or in older houses. I think it is getting worse with every new building.
That's because the focus on energy efficiency means installing HVAC that recirculates and setting the recirculation ratio to as high as they can get away with. Before that, buildings were taking in 100% outside air to heat/cool, which was extremely inefficient but also gave no chance for CO2 to build up.
> buildings were taking in 100% outside air to heat/cool
This hasn't been true since fireplaces stopped being used for heating. Even very basic furnaces, such as the coal-fired one my grandparents had in the 1940s, recirculated the air inside the house. (It was an unforced / gravity "octopus furnace", fired with soft coal, with the house temperature controlled via a damper on the chimney.) But it took its combustion air from inside, and was vented via a chimney to the outside, so the house was constantly at a very small negative pressure, and combined with the natural draftiness of prewar construction there was naturally some fresh air intake. But certainly not 100%!
I think it's the newer high-efficiency furnaces where you start to have very high recirculation ratios and consequent CO2 issues. Because they pull combustion air from outside, there's no incidental exhausting of interior air to outside (which would tend to pull in outside air through gaps in the building envelope). Great for efficiency, though.
Vaisala makes good probes, acceptable for use in life science applications. They are expensive and you need an rs485 adapter for the ones I used. The serial protocol is nice and simple though.
Any ventilator. Heat recovery is optional - it is really hard to recover heat from lukewarm air without actually recirculating most of it.
The pressure drop requires more electricity due to more power in the pumps, making it a relatively bad trade - only heatpipe systems are worth anything.
The recommendation here in Denmark is to air out for ~10 minutes, 3 times a day, ideally with all doors and windows open, making sure to get good airflow between rooms.
I think very few people actually air out that much, but I've found that it's very helpful for my sleep quality to air out just before I go to bed. Airing out in the morning also helps eliminate moisture from showering, as my bathroom doesn't have a window, nor any forced ventilation.
This is one of my regular arguments in the office, I open a window, someone says "aren't you cold??" and I say "I don't want it colder, I want it fresher, less stuffy".
I've certainly worked in poorly ventilated offices, and my bedroom is even worse. But I don't think I've ever gotten dizzy in an office. Is this something that affect different people at different rates?
There was an NBA coach who use to obligate his players to sleep with at list some inches/centimeters of air access in their windows hotel rooms the night before playing an important game/match. Don't remember what Team.
I've worked on environmental sensing iot projects and have seen the cost of co2 sensors. Almost all the cheap ones are VOC sensors which infer a co2 level by assuming the VOC output is from humans (rather than paint for example).
Given the cost of the device I would be amazed if it wasn't a VOC based sensor. The cheapest CO2 sensors I've seen are well over $250, even in bulk. CO2 is quite innert, so it requires very precise and accurate components
Looking at their materials[1], it's IR based and needs calibration. I'm sure it's output is interesting, but likely not super accurate given their started assumptions for the calibration process. Better sensors may be required before drawing any conclusions!
i’ve noticed this casually as well. i bought an airthings wave plus [0] a few months ago and the co2 and total voc readings seem pretty (but not perfectly) correlated.
i live in a drafty pre-war building and my co2 peaks at around 1500-1600 ppm at night with doors and windows closed. it troughs at around 500 during the day when i have the doors and windows open (~400 is ambient from what i understand). tvocs typically peak around 600 ppb and trough at around 20 (under 100 is considered safe iirc), with the same cycle as co2.
The "TFA Dostmann AirCO2ntrol" devices are popular in Germany. Searching for "co2 meter" on Amazon.com one of the top results is an identical looking device.
It measures with an infrared spectroscopy-based sensor, which should be quite accurate. There are a few good software packages for recording data, e.g. https://github.com/vfilimonov/co2meter.
Repost from my comment above, but for a couple hundred bucks you can get an accurate CO2 sensor that reads out via USB-serial to a computer. I use them at work and we've shown they are quite good over the long term. Plus to recalibrate, you can just take them outside. https://www.co2meter.com/products/k-30-co2-sensor-module
I have developed custom Ethylene sensors in the past for customers, and Dynament (UK) is a manufacturer that I can definitely recommend if anyone wants to do this and go down the DIY electronics route without having to dig through a bunch of Chinese products to find the "right one". https://www.dynament.com/products/gas-sensors/standard-non-e...
Cool! I worked at an ethylene-sensing IoT startup (fruit ripeness natch). What was the core sensor you used? (We were using off-the-shelf, but somewhat pricey, electrochemical sensors)
Just test/calibrate them outside (400-ish ppm). Even if absolute measurements are bogus, they should do just fine to figure out whether it’s time to open the window..
Would be interested to find out because if its just uncalibrated plotting out the relative differences it still would be useful (e.g. seeing a X% increase on whatever scale the sensor using at night versus day could provide enough of an indicator that something is going on and more investigations are warranted.)
Thanks. I was about to get a cheap one on Amazon :D
Sort of related, I'm living in a newly constructed house and I'm interested to know the indoor air quality. Any recommendation for a comprehensive in door air quality test solution (either device(s) or hire someone maybe)?
MH-Z14 or Z19 are cheaper, around 25€. With optical measurement. I have a few of them, they seem accurate enough. I calibrate them every 6 months by placing them outdoors.
It looks like things have moved on quickly since the other year when I was more involved in this! This company does some good products, some of which are fairly easy to interface: https://www.gassensing.co.uk/products/
This is especially pronounced at high altitude, and when running a furnace in the winter. I keep large black tents (4x4 ft or 2x4) in every bedroom in the house, and grow kale, spinach, chard, peas, tomatoes, etc inside (with handmade COB LED lights).
I don't have any sensors to get a real idea of the difference in CO2 it makes, but it allows us to run the furnace less at night (heat from the lights), and makes a noticeable difference in humidity ( very dry air here ).
Also, we get about 1-2 family meals / week of food at full capacity ( total 4x8 grow space and 800 watts of light running only at night ).
Not economical and takes a lot of maintenance, but it's a fun hobby from which we all feel the benefits.
Have the police visited? Sounds like the sort of thing they'd think would be a grow house. (....a marijuana grow house, I mean, not one for eggplants and radishes)
I think it’s as simple as biomass produced vs biomass consumed, and I agree a 4x4 garden is not going to fully replace O2 for two sleeping adults. I’ve experimented with building tower setups which would allow 3-5 times the biomass growth in the same space, but it’s a real pain tending to a garden at eye level, and introduces all kinds of new catastrophic failure possibilities when you have water above high power lights.
Theres no difference in heating efficiency for any source. Heat is heat and it doesn't really matter if it's generated from a heating element in a furnace or an LED light. And with the light you're at least getting dual use out of it.
If they have a gas furnace it might be different but that would also depend on how their electricity is generated.
Extra $38/m, and because the heat is targeted we can leave the unoccupied areas colder.
Certainly not an efficient way to heat the house, but the main concern is oxygen and not generating co2 with the furnace, then air filtration (SLC nasty air), then humidity, then food, THEN heating.
Assuming the furnace is electric too, they should both be the same efficiency, since 100% of the power is being eventually turned into heat, unless the light from the LEDs are going outside.
I really wish I'd read these comments and realised the experiment isn't finished before scrolling up and down the article for five minutes trying to find the conclusion.
> I really wish I'd read these comments and realised the experiment isn't finished before scrolling up and down the article for five minutes trying to find the conclusion.
Gwern.net has useful heading information on each page. This particular one says:
Gwern continues to be one of the most authentically curious and transparent researchers around. I highly recommend perusing his essays. Thank you and keep up the excellent output.
With every similar news I feel dumb. Because my parents and my grandparents used to say same things. It was easy to dismiss all the advice as grumbling, but I really should refresh air before sleeping, humidify air in heating season, eat more vegetables... etc. etc.
Not all of it was correct. My parents' generation "learned" to avoid eating fats to not become overweight. My grandmother knew that you shouldn't eat fresh bread before it cooled down (unhealthy or so).
We researched the latter recently and found out, that this idea was spread after the war so that the children would not eat too much of the freshly baken bread, because it tasted better. No health implications at all.
The problem is that parental figures previously based such general information on gut feelings, personal anecdotes and old wives tales. A lot of what parents say can be correct, but when there is a lack of information to fill the gaps to a childs understandable inquisitiveness it's filled with ignorance or scorn by the parents that are going through the motions who have no answer. It's an interesting dynamic with the resources available for information to the general public that it will be the children that can quash misconceptions perpetuated by parents. We all, including future generations, will become better parents for it.
I agree, but at the same time I feel that we are losing some of this common folk knowledge. It is strange, because we are in this information age, however it's full of noise. I'm not saying that it's bad to know how things are extensively with scientific rigor. It's good, but we are sometimes throwing the baby out with the bathwater.
My parents had limited vocabulary, but in a way they meant the same thing. Stale air (a hopefully faithful translation from my language) can have many meanings, but in context it means air with high CO2 concentration. I'm wondering how much of this is also the disconnect caused by fast technological progress and evolving language with it.
I thought the same. Rearing a newborn recently, I find that much of the parental/pre-parental advice works well. However, I just now realized, they probably actually understood the problems. But since only the advised actions stuck in my mind, without the problem analysis, I came to think they would act on gut feelings. I think this is sort of a child/grandchild bias.
This leaves aside parental scorn/ignorance as you describe it. Sounds like stressed-out parents, if I may say so. However, I don't know how future generations will get better at it, only that you may get better at it.
well it would have helped if they explained it or knew why. they just “felt” those things. if I knew it’s because co2 was building up and it can make you dizzy, i’d open the window
There's one big problem with this entire idea of co2 levels affecting sleep quality or humans in general:
Even though there are cognitive effects of CO2, most often the CO2 levels in indoor rooms are simply a sign of low oxygen levels. In fact, there should be an inverse relationship between CO2 and oxygen in rooms. So an experiments would need to take this into account and supply pure oxygen to make up for the oxygen that has been used up.
It should be noted though, that the effects of low oxygen are already very well known and well understood, thanks to decades of research funded by air and space agencies.
It should therefore be pretty easy for CO2 researchers to control the outcomes of their experiments against the known physiological effects of hypoxia, to determine what effects are actually caused by CO2.
And aside from that, the dosages being discussed here are far, far lower than would be a noticeable dent in the amount of oxygen in the atmosphere. 1000 ppm CO2, the lower bound of observed cognitive effects, is 0.1% CO2, way less than the point where hypoxia is known to cause problems. The atmosphere is 20.9% oxygen at sea level and while I am not an expert in the math of partial pressure, a decrease of atmospheric oxygen to 20.8% doesn't strike me as sufficient to explain the observed effects. That's a 0.4% decrease in the partial pressure of oxygen, or about the equivalent of a 300 foot increase in altitude, or taking an elevator to the 20th floor of a building, nowhere near enough increase in altitude to make you light-headed.
The symptoms of slight sub-clinical hypoxia are in line with the observed effects of people in high CO2 office rooms: headaches, concentration problems, tiredness, etc.
In a closed small room, the oxygen is mostly used up after a couple of days.
One person in a small tightly closed room will lower the oxygen level significantly, by 5-10% (consumption is around 20 cubic feet, and a small room has about 200 cubic feet oxygen in volume in total)
CO2 and oxygen work in tandem in the human body, and studies in the medical field have shown that an increase in carbon dioxide increases breathing rate, breathing volume, heart rate and metabolic rate.
The result is an increased need for oxygen, which will not be met in a closed room.
Thus I speculate that an increase in CO2 with an accompanying increase in oxygen (or at least a stable flow) will mostly negate the observed symptoms.
My preliminary working theory would be that the previously observed effects from high CO2 in rooms (office rooms for example) are due to the interaction of both high CO2 and low O2.
That's intuitively appealing but when you look at the numbers it's almost certainly false. When CO2 goes from 400 ppm to 1000 ppm then oxygen will go from 21000 ppm to 20400 ppm, a 3% drop which isn't going to be enough to change anything.
No, the body does not use the same amount of oxygen, as the amount of CO2 it exhales.
The amount of oxygen used is way higher.
A person consumes 19 cubic feet of oxygen a day.
Edit: I looked at the composition of inhaled and exhaled air, and now I realize the reason O2 is being taken out of the air in higher amounts than CO2 is introduced, is that the exhaled amount of carbon dioxide is not the total amount of carbon dioxide that has been created in the body.
When the CO2 in the room gets higher, more CO2 is actually taken up again from the room back into the human body, with the exhale rate staying relatively constant. Or in other words, a significant part of the increase in CO2 in the system human <-> room is actually in the human, not in the room. The room measurement thus covers only a part of the CO2 being produced in total, and only the unknown total amount of CO2 produced reflects the totality of O2 being used up.
This means a change of 1000 ppm of CO2 in the air will mean a higher amount of oxygen has been used up.
Most of the CO2 stays in the body, which ultimately means that significantly more O2 is used up than CO2 is introduced back into the air again.
The comment about submarines is highly interesting to me, I will look into the studies! If you have any sources about that to share, I would love to read them.
They do move in tandem on a molar basis, but because there is so much more O2 in the air, even very high concentrations of CO2 have barely changed the concentration of O2.
Readit News
What I found:
-Just a couple of hours in a office, without ventilation spikes the co2 enough to make everyone dizzy and tired by the end of the day. Keeping eye on the meter and ventilating properly, increased everyones productivity and people werent so tired by the end of the day.
- Classrooms, with 20-30 people are as bad. co2 rises really fast and makes people dizzy. Most often ventilation is too low, as a cost saving measure.
-Closing bedroom door, sleeping alone made bedroom as bad by the morning than classroom or office.
-Main culprit seems to be our perfection with insulating and making rooms airtight. I do live in a cold climate, so having open vents or windows is not common half the year. It seems it has not been such a big issue before plastic windows or in older houses. I think it is getting worse with every new building.
Sorry, but this is just wrong and is the type of "accepted wisdom" that holds back construction, particularly here in the UK.
Repeat: ventilation and permeability are different things.
Yes, permeability can achieve some ventilation but it comes at the cost of:
1) Not being reliable; it is dependent on pressure deltas around the dwelling.
2) Being potentially deleterious to the fabric of the building where escaping warm air cools and water condenses on surfaces in the fabric.
3) Being wasteful of energy.
The solution is to separate the two:
1) Seal the fabric totally, bearing in mind vapour permeability. The seal should be on the warm side of the insulation.
2) Install a ventilation system which provides reliable fresh air and, ideally, exchanges the heat leaving the building with the fresh air coming in.
We can no longer rely on folksy wisdom. Let's engineer our houses.
I recently added A/C cooling to a previously heat-only house, and I took the opportunity to ask the company to explain some quirks in the existing system, like how the ventilation fan in the laundry room is on the same breaker as the central heating, and had a hidden timer attached to it.
The house was built (early 1990s) with a particularly powerful vent fan in the laundry room which was on (regardless of the wall switch) a certain number of hours a day, and the forced-air system had an air intake outside the house which mixed with the return air before hitting the filter.
This was all sized such that all the air in the house would be replaced about once every 24 hours, according to WA state's VIAQ ("Ventilation and Indoor Air Quality") code.
That's all been superseded by the International Mechanical Code and International Residential Code.
South Africans are (at least historically) quite different in this respect. Everyone is cold in the winter due to complete disregard for insulation (at least, when compared to Europe). People also don't get layering. The comments about construction do hold mostly. In the warmer areas of the country usually you are cold in the winters for only a couple hours per day.
When we go overseas we tend to open all the windows. Maybe this is because we are not used to long winters.
My grandparents were experts at opening select windows in their houses to create drafts in the pre-aircon age.
There is a meme: "If a guy invites you to a braai at his home at 3am, it really is a braai."
* https://www.youtube.com/watch?v=CIcrXut_EFA
Mold is not a ventilation problem, but rather a moisture control problem. Keep the humidity down (especially with whole house dehumidifiers), and eliminate condensation points (by eliminating thermal bridging), and it goes away.
While the above video, which is from the really good channel by Matt Risinger, is a good introduction, I recommend you also check out the building science stuff put out by Joseph Lstiburek for a more science-y explanation:
* https://en.wikipedia.org/wiki/Joseph_Lstiburek
On the "perfect wall":
* https://buildingscience.com/documents/insights/bsi-001-the-p...
Presentation on control layer (especially starting around 15m):
* https://www.youtube.com/watch?v=rkfAcWpOYAA
Good webinar:
* https://www.youtube.com/watch?v=sBcNFeiWjrg
My house is absolutely frigid during the winter, and I got quote for resealing it. He told me that afterwards I am either going to have to leave my windows open (no thanks!) or live with mold.
I've heard that you can install vents, but can't find useful info. My grandparents had a chute vent, and it somehow became a breeding ground for flies and all sorts of ichies. Not sure why.
And short vents sound to me like an always open wondow, which just brings in the cold.
I want the insulation, the circulation, the breathability and the warmth. Is there any way to have it all?
During the lecture he mentioned the figures for CO2 concentration that led to symptoms, e.g. dizziness, sleepiness etc.
The reading at the end of the lecture showed that it was over the recommended limit, and well beyond the threshold that causes people to get sleepy and lose concentration. (I believe it was less than 400ppm at the start and thousands ppm afterwards?)
A simple demonstration using an older building crammed full of students in a closed space, but it was apparently quite impactful in showing the students how there are a lot of features of interior design architecture that aren't really addressed and are only coming to the fore recently.
I’ve attributed this to “fewer people, fewer distractions.” However, with a CO2 component... hmm.
Well, there is another project idea. Arduino with a CO2 sensor and plotting a running total. Or not displaying and instead have a “I feel productive” dial that would allow for correlation to the recorded data.
Nearly every standard rectangular building should be in actuality built with the energy efficient building design in mind, but we don't... out of simple mental oversight and in the increased cost in construction.
https://kammaliyaa.files.wordpress.com/2013/01/figure-11.jpg
Literally, we could save 20% to 30% in energy costs with every building with possibly only 10% to 15% increase in cost of construction, but we simply don't because we have no congregate valuation of resource consumption, only individual guilt.
Then this must have been before 2016. Atmospheric CO2 concentration has always been higher than 400 ppm since that year.
Bigger CO leaks are extremely dangerous, many people lost their lives because of heating systems.
If you can, change to Oil Flow system with burner outside the house and far and aislated from humans. Or, if you can, electrical system. CO from gas is Really Very dangerous.
(using the word "very" is against Mark Twain's advice[1], and using the word "really" is against my own advice, but there are exceptions, here above was one)
1:
“Substitute "damn" every time you're inclined to write "very" ; your editor will delete it and the writing will be just as it should be.”
2- "delete all instances of "really" in you text, and your writing will be better"ImmerseintheImmensity, Also unknown as InfimousInfinity, Also unknown as ParadoxParalax
It can integrate with HomeBridge and has a good API and unlike a lot of IOT stuff it’s well supported and stable.
I do belive now though that even having recreational level sensor will give you at least understanding overall co2 levels and this something we should look into more.
I founs a paper using the same sensors that measured co2 in schools. In all cases, at certain times the measurement was higher than norm. occassionally over 2000. I can now understand much better kids getting sleepy and unable to concentrate in classroom.
Paper sadly in Estonian only: https://www.google.com/url?sa=t&source=web&rct=j&url=http://...
I have a sensor and try to keep readings low. My girlfriend isn't quite convinced though, especially in winter....
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That's because the focus on energy efficiency means installing HVAC that recirculates and setting the recirculation ratio to as high as they can get away with. Before that, buildings were taking in 100% outside air to heat/cool, which was extremely inefficient but also gave no chance for CO2 to build up.
This hasn't been true since fireplaces stopped being used for heating. Even very basic furnaces, such as the coal-fired one my grandparents had in the 1940s, recirculated the air inside the house. (It was an unforced / gravity "octopus furnace", fired with soft coal, with the house temperature controlled via a damper on the chimney.) But it took its combustion air from inside, and was vented via a chimney to the outside, so the house was constantly at a very small negative pressure, and combined with the natural draftiness of prewar construction there was naturally some fresh air intake. But certainly not 100%!
I think it's the newer high-efficiency furnaces where you start to have very high recirculation ratios and consequent CO2 issues. Because they pull combustion air from outside, there's no incidental exhausting of interior air to outside (which would tend to pull in outside air through gaps in the building envelope). Great for efficiency, though.
Not a great choice if you ask me.
It does't not worth the money to live in Beijing, no matter how rich you can get there, and you can get rich there, but it simply does not worth.
Your life is more important, specially if you have kids.
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The pressure drop requires more electricity due to more power in the pumps, making it a relatively bad trade - only heatpipe systems are worth anything.
I also remember often getting really dizzy working in my previous office, and I couldn't understand why, maybe you're on to something.
Now I'm wondering how all of that has affected my health along the years
I think very few people actually air out that much, but I've found that it's very helpful for my sleep quality to air out just before I go to bed. Airing out in the morning also helps eliminate moisture from showering, as my bathroom doesn't have a window, nor any forced ventilation.
Your anecdata has cemented it as fact(tm).
Only if you skimp on HRV system (which are cheap and works like magic).
It's lame to say it's getting worse, when it's actually getting better.
Given the cost of the device I would be amazed if it wasn't a VOC based sensor. The cheapest CO2 sensors I've seen are well over $250, even in bulk. CO2 is quite innert, so it requires very precise and accurate components
[1]: https://www.netatmo.com/en-gb/helpcenter/air-care/4/installa...
i live in a drafty pre-war building and my co2 peaks at around 1500-1600 ppm at night with doors and windows closed. it troughs at around 500 during the day when i have the doors and windows open (~400 is ambient from what i understand). tvocs typically peak around 600 ppb and trough at around 20 (under 100 is considered safe iirc), with the same cycle as co2.
[0] https://airthings.com/us/wave-plus/
By 2100, we may be at 800ppm if we continue and/or accelerate fossil burning (4 degrees C trajectory). https://www.co2.earth/2100-projections
Already a middling stuffy room, and would increase indoor levels 400ppm over today.
It measures with an infrared spectroscopy-based sensor, which should be quite accurate. There are a few good software packages for recording data, e.g. https://github.com/vfilimonov/co2meter.
https://smartairfilters.com/en/blog/how-accurate-are-common-...
Sort of related, I'm living in a newly constructed house and I'm interested to know the indoor air quality. Any recommendation for a comprehensive in door air quality test solution (either device(s) or hire someone maybe)?
I don't have any sensors to get a real idea of the difference in CO2 it makes, but it allows us to run the furnace less at night (heat from the lights), and makes a noticeable difference in humidity ( very dry air here ).
Also, we get about 1-2 family meals / week of food at full capacity ( total 4x8 grow space and 800 watts of light running only at night ).
Not economical and takes a lot of maintenance, but it's a fun hobby from which we all feel the benefits.
Dear God, what's your power bill? There's no way a LED lights heat is as efficient as just using the furnace.
edit: I meant cheap, not efficient.
If they have a gas furnace it might be different but that would also depend on how their electricity is generated.
Certainly not an efficient way to heat the house, but the main concern is oxygen and not generating co2 with the furnace, then air filtration (SLC nasty air), then humidity, then food, THEN heating.
edit: we vent the tents directly at our beds
Gwern.net has useful heading information on each page. This particular one says:
> modified: 13 Dec 2018; status: in progress;
Presumably the status tag will be modified to "draft" or "finished" once conclusions are available. https://www.gwern.net/About#confidence-tags
We researched the latter recently and found out, that this idea was spread after the war so that the children would not eat too much of the freshly baken bread, because it tasted better. No health implications at all.
My parents had limited vocabulary, but in a way they meant the same thing. Stale air (a hopefully faithful translation from my language) can have many meanings, but in context it means air with high CO2 concentration. I'm wondering how much of this is also the disconnect caused by fast technological progress and evolving language with it.
This leaves aside parental scorn/ignorance as you describe it. Sounds like stressed-out parents, if I may say so. However, I don't know how future generations will get better at it, only that you may get better at it.
Even though there are cognitive effects of CO2, most often the CO2 levels in indoor rooms are simply a sign of low oxygen levels. In fact, there should be an inverse relationship between CO2 and oxygen in rooms. So an experiments would need to take this into account and supply pure oxygen to make up for the oxygen that has been used up.
It should therefore be pretty easy for CO2 researchers to control the outcomes of their experiments against the known physiological effects of hypoxia, to determine what effects are actually caused by CO2.
And aside from that, the dosages being discussed here are far, far lower than would be a noticeable dent in the amount of oxygen in the atmosphere. 1000 ppm CO2, the lower bound of observed cognitive effects, is 0.1% CO2, way less than the point where hypoxia is known to cause problems. The atmosphere is 20.9% oxygen at sea level and while I am not an expert in the math of partial pressure, a decrease of atmospheric oxygen to 20.8% doesn't strike me as sufficient to explain the observed effects. That's a 0.4% decrease in the partial pressure of oxygen, or about the equivalent of a 300 foot increase in altitude, or taking an elevator to the 20th floor of a building, nowhere near enough increase in altitude to make you light-headed.
In a closed small room, the oxygen is mostly used up after a couple of days.
One person in a small tightly closed room will lower the oxygen level significantly, by 5-10% (consumption is around 20 cubic feet, and a small room has about 200 cubic feet oxygen in volume in total)
CO2 and oxygen work in tandem in the human body, and studies in the medical field have shown that an increase in carbon dioxide increases breathing rate, breathing volume, heart rate and metabolic rate.
The result is an increased need for oxygen, which will not be met in a closed room.
Thus I speculate that an increase in CO2 with an accompanying increase in oxygen (or at least a stable flow) will mostly negate the observed symptoms.
My preliminary working theory would be that the previously observed effects from high CO2 in rooms (office rooms for example) are due to the interaction of both high CO2 and low O2.
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The amount of oxygen used is way higher.
A person consumes 19 cubic feet of oxygen a day.
Edit: I looked at the composition of inhaled and exhaled air, and now I realize the reason O2 is being taken out of the air in higher amounts than CO2 is introduced, is that the exhaled amount of carbon dioxide is not the total amount of carbon dioxide that has been created in the body.
When the CO2 in the room gets higher, more CO2 is actually taken up again from the room back into the human body, with the exhale rate staying relatively constant. Or in other words, a significant part of the increase in CO2 in the system human <-> room is actually in the human, not in the room. The room measurement thus covers only a part of the CO2 being produced in total, and only the unknown total amount of CO2 produced reflects the totality of O2 being used up.
This means a change of 1000 ppm of CO2 in the air will mean a higher amount of oxygen has been used up.
This could potentially account for why no ill effects of high co2 were found in submarines. Presumably o2 supply there is well maintained.
Do household air quality standards include o2 levels?
The comment about submarines is highly interesting to me, I will look into the studies! If you have any sources about that to share, I would love to read them.