6 ms·

The more we study it, the more we learn how harmful the air inside our homes is. That's why fresh air is key. Crack a window or two open. Buy an air monitor th

The more we study it, the more we learn how harmful the air inside our homes is. That's why fresh air is key. Crack a window or two open. Buy an air monitor that monitors CO2 (good proxy for overall freshness), VOCs (sometimes these build up much faster than CO2), and PM2.5. If CO2 or VOCs are high, open windows more. If PM2.5 is high and coming from outdoors, turn on an air filter. Yes, this means your heating and cooling bill will be a bit higher. But for your health and concentration, it's worth it.

fnordian_slip 1y ago
I bought an aranet 4, it's quite eye opening how you sometimes get a lot of CO2 buildup without even noticing. I mostly solve any issues with VOC by "Stosslueften", but if that's not enough because the air quality outside is too bad, a CR box is an effective, easy to build and almost perfectly silent design, especially if you do it with decent quality pc fans.
- agwa 1y ago
  A CR box only removes particulates, not VOCs. To remove VOCs, you need a filter with many pounds of activated carbon.
  - fnordian_slip 1y ago
    Ah, my bad, I thought that everyone built CR boxes with carbon, but that's not the case. The standard design doesn't use carbon at all. Thanks for the correction.
Etheryte 1y ago
This is advice that gets thrown around a lot, but it's missing the important bit of how to buy a meter that's both reasonably accurate and affordable. There are countless articles online showing how widely commonly sold meters vary in their readings. What's more, paying more often does not mean you'll get a more accurate reading. Sure, there's diminish returns and past a certain point it doesn't matter, but many meters are completely unreliable.
- crazygringo 1y ago
  The Awair Element is the best option for consumers who want something easy and relatively inexpensive. Hackers may prefer other options.
  - entropie 1y ago
    Awair is awesome and very sensitive but pretty expensive (150€ for mine) but integrates well in HA
- Night_Thastus 1y ago
  The problem is there are a lot of effectively 'fake' CO2 monitors. They can't monitor CO2, they only monitor something else and work backwards to estimate CO2 levels. The cheapest real ones I've found are on the order of ~$150
  - buckle8017 1y ago
    Unless your CO2 monitor has purge gas to calibrate it's going to underestimate indoor CO2. They all assume that they will be exposed to atmospheric concentrations of CO2 at least once a week.
    - imp0cat 1y ago
      In their defense, they usually mention this requirement in the manual.
      - buckle8017 1y ago
        Sure but do you take your CO2 meter for a walk?
        Etheryte 1y ago
        And in similar vein, when was the last time you read the manual for a household appliance?
privatelypublic 1y ago
Those monitors are useless. Unless they're VERY expensive they only show a change over a short period of time
- homebrewer 1y ago
  My cheap Chinese PM2.5 sensors (PMS7003) installed both outside and inside provide accurate readings all year round. They track official government data very closely (monitored by expensive and certified equipment that goes through calibration every year). My problem with this advice is not that it's difficult to measure pollution levels (it really isn't), but that there's no "fresh air" outside for many of us. In many parts of the world, the air is significantly worse outside than inside even without running an air purifier (and with a purifier the difference in particulate levels can run into 100× or more during winter). Some years ago I looked at the few papers that measured the difference in gaseous pollutants (like NO2 and SO2) inside and outside with windows open and windows closed, and for some reason closed windows do provide limited protection against them. Nobody really understands why AFAIK, it shouldn't work that way since they're mixed with air in a gaseous mixture from which they can't be filtered out without a specialized chemical filter, but it does help.
  - agwa 1y ago
    We should clarify what type of sensors we're talking about. It seems to be easier to find accurate inexpensive sensors for particulate matter (PM) and CO2 than it is for VOCs.
  - mschuster91 1y ago
    > and with a purifier the difference in particulate levels can run into 100× or more during winter No surprise. A lot of homes are still being heated by combustion. Gas heating is relatively clean if the burners are properly maintained, oil burners are a hit and miss, but everything else... wood pellets are often declared as the "green" alternative, but that's only valid for CO2 (and even there, the actual benefit for the climate is massively debated) - these things spew an awful lot of particulate emissions, brick-wood ovens are even worse, especially when people illegally throw in too humid firewood or, worse, garbage that has no business being incinerated outside of an industrial high temperature facility with proper exhaust stack treatments. Unfortunately, as you say, in many parts of the world people are too poor to afford proper heating fuel sources, and it's costing them and their countries so much productivity and money in the long run... and in developed countries, there still are a sizable amount of people who have no idea how to properly heat their ovens, how to prepare their firewood or that just outright skirt garbage disposal fees. Jörg Kachelmann, founder of the weather service Meteomedia, has extensively written about that topic in the past [1] and keeps ranting on social media about it under #holzofengate. [1] https://www.t-online.de/nachrichten/panorama/id_84671908/kachelmanns-donnerwetter-feinstaub-aus-holzoefen-die-gemuetlichen-dementoren.html https://www.t-online.de/nachrichten/panorama/id_84671908/kac...
seper8 1y ago
Crack a window open (Except if you live in a city)
cameronh90 1y ago
The challenge with opening the window isn't even the cost - which is substantial - from about £250/month to £400/month if I have my windows open even a little bit. The bigger challenge is with my windows open, my heating just can't even keep up! It'll be maxed out and only 18c. I do the German-style luften twice a day, but if our interiors are just absorbing the compounds and releasing it when the windows are shut, then that's not even going to help much.
- b112 1y ago
  Get a heat recovery exchanger. https://natural-resources.canada.ca/stories/spotlight-energy-efficiency/what-s-heatenergy-recovery-ventilator-need-one https://natural-resources.canada.ca/stories/spotlight-energy...
  - cameronh90 1y ago
    Indeed, but a traditional MVHR would require ductwork which isn't common in the UK and often there isn't really any space to route it. I have been investigating easier to retrofit decentralised MVHR systems such as the Prana Recuperator, Ventaxia Tempra and the Blauberg Vento. They can be noisy (not a problem for me, I don't mind noise) and quite expensive as you have to fit a number of units in different rooms, but still easier than retrofitting ducting.
  - mrktf 1y ago
    It is called recuperator. If it is possible to retrofit i suggest to use mounted in attic (it will be silent). Otherwise, if you want higher quality not and these `breathing` types the box will have similar size like air conditioner (search: mitsubishi vl-100eu5-e)
  - esperent 1y ago
    Good advice if you can do it, but this isn't possible for most people, for example if you're renting or you're in an apartment.
  - whatevaa 1y ago
    It's not something you just add. It's a capital renovation. Requires ducting. Tons of homes don't even have ducting.
coder543 1y ago
Outside air isn’t a panacea. There is often plenty of pollution right outside your window unless you live on an idyllic beachfront property. The humidity level outside is also rarely what you want in your home, whether it is too high or too low. Much better than cracking a window is the use of ERVs (energy recovery ventilators) and air filters on the incoming air. An ERV is a fairly simple device that exchanges air with the outside while mitigating the loss of energy and humidity. Any modern home build likely has an ERV as part of the design, but it’s not like they can’t be retrofitted, and I’ve even seen some DIY-friendly window unit ERVs (but I’ve never heard if those are any good).
- Hnrobert42 1y ago
  I live in an apartment in Washington DC. Opening a window reduces CO2 and VOCs. An ERV is great if you can afford it, but cracking the window is still quite reasonable.
  - coder543 1y ago
    CO2 and VOCs, but what about PM2.5 and PM10? What about pollen? What about humidity control? Cracking a window is also costly, since it directly raises your heating and cooling bills. It's just an "invisible" cost that's easy for some people to ignore since it's hard to directly measure. An ERV pays for itself over time, so it's more a question of whether you can afford to just crack a window? Living in an apartment makes this difficult because your landlord may not let you improve this situation, but just ignoring the cost of opening a window doesn't make the cost go away.
    - encom 1y ago
      Don't leave your windows open all the time. Open them for 5-10 minutes at least once a day. Heating air is cheap, it's heating all the other mass in your home that's hard, so don't let it cool down. If you live somewhere uninhabitable like Texas, change heating for cooling.
      - 1y ago
deleted 1y ago
[deleted]
jbd0 1y ago
I built a window vent with a variable-speed computer fan and an esp8266 that communicates with a CO2 monitor and raises the speed when the CO2 gets too high. I have a very fine mesh on the window screen that's designed to filter out pollen and dust. It works really well. I usually only turn it on at night, because that's when my wife and I are both in the room and the CO2 can really build up.
- J_Shelby_J 1y ago
  I use an ikea air filter that just so happens to fit perfectly in the window + a smart outlet and co2 sensors. I’d like to do a custom build like you so the fan speeds are variable.
nobodyandproud 1y ago
Good advice on the CO2 monitor. Cheap and surprisingly effective. I haven't considered the VOC--any recommendations? As an aside, I open up my window, but sometimes smokers decide to take a break outside and...well. Other times, I have neighbors barbecuing. If I don't shut the windows quickly I've just replaced stale and somewhat harmful air with oxygenated and definitely harmful air.
- twothamendment 1y ago
  I've been using the Awair Element for years. It helped me decide to install an air exchanger an to swap the gas range with induction. Bonus, it has a local API for pulling data. I have a purple air sensor outside. One day I'll get around to making the air exchanger smart enough to turn off when the smoke from fires makes the air outside worse than inside, it turn off the air exchanger when inside air is good enough, etc.
- prewett 1y ago
  I've been happy with the AirGradient One, which does have VOC measurement, as well as CO2, and PPM 2.5. It seems that VOC on the hardware side is relative, so the amount is just compared to a baseline (last 24 hours in the case of the AirGradient One). Also, VOCs are everywhere, but not necessarily harmful: cooking will spike your VOCs, but that's very different than having a can of varnish open.
modeless 1y ago
Every home should have a heat recovery ventilation system. It gives you fresh outside air in the whole home, but filtered to remove PM2.5 and without the inefficiency.
- cryptonector 1y ago
  Can you say more? Maybe link to a useful page or product(s)?
  - throawayonthe 1y ago
    https://en.wikipedia.org/wiki/Heat_recovery_ventilation https://en.wikipedia.org/wiki/Heat_recovery_ventilation
- IncreasePosts 1y ago
  Many new builds will, especially in places with required efficiency standards, but the average house in the US is 40 years old. And leaky as hell.
lupusreal 1y ago
> Yes, this means your heating and cooling bill will be a bit higher. Not even necessarily. People these days are accustomed to keeping their homes at comfortable T-shirt temps even in the dead of winter, but if you dress appropriately for the season you can drop your indoor temperatures 20F or more from what people normally set the thermostat to while still maintaining a safe margin to keep your pipes from freezing.
jerryjerrygeri 1y ago
Yeah thermodynamics though; generation of electricity for that extra heat or cold waste heats up planet.

fnordian_slip 1y ago

I bought an aranet 4, it's quite eye opening how you sometimes get a lot of CO2 buildup without even noticing. I mostly solve any issues with VOC by "Stosslueften", but if that's not enough because the air quality outside is too bad, a CR box is an effective, easy to build and almost perfectly silent design, especially if you do it with decent quality pc fans.

agwa 1y ago
A CR box only removes particulates, not VOCs. To remove VOCs, you need a filter with many pounds of activated carbon.
- fnordian_slip 1y ago
  Ah, my bad, I thought that everyone built CR boxes with carbon, but that's not the case. The standard design doesn't use carbon at all. Thanks for the correction.

Etheryte 1y ago

This is advice that gets thrown around a lot, but it's missing the important bit of how to buy a meter that's both reasonably accurate and affordable. There are countless articles online showing how widely commonly sold meters vary in their readings. What's more, paying more often does not mean you'll get a more accurate reading. Sure, there's diminish returns and past a certain point it doesn't matter, but many meters are completely unreliable.

crazygringo 1y ago
The Awair Element is the best option for consumers who want something easy and relatively inexpensive. Hackers may prefer other options.
- entropie 1y ago
  Awair is awesome and very sensitive but pretty expensive (150€ for mine) but integrates well in HA
Night_Thastus 1y ago
The problem is there are a lot of effectively 'fake' CO2 monitors. They can't monitor CO2, they only monitor something else and work backwards to estimate CO2 levels. The cheapest real ones I've found are on the order of ~$150
- buckle8017 1y ago
  Unless your CO2 monitor has purge gas to calibrate it's going to underestimate indoor CO2. They all assume that they will be exposed to atmospheric concentrations of CO2 at least once a week.
  - imp0cat 1y ago
    In their defense, they usually mention this requirement in the manual.
    - buckle8017 1y ago
      Sure but do you take your CO2 meter for a walk?
      - Etheryte 1y ago
        And in similar vein, when was the last time you read the manual for a household appliance?

privatelypublic 1y ago

Those monitors are useless. Unless they're VERY expensive they only show a change over a short period of time

homebrewer 1y ago
My cheap Chinese PM2.5 sensors (PMS7003) installed both outside and inside provide accurate readings all year round. They track official government data very closely (monitored by expensive and certified equipment that goes through calibration every year). My problem with this advice is not that it's difficult to measure pollution levels (it really isn't), but that there's no "fresh air" outside for many of us. In many parts of the world, the air is significantly worse outside than inside even without running an air purifier (and with a purifier the difference in particulate levels can run into 100× or more during winter). Some years ago I looked at the few papers that measured the difference in gaseous pollutants (like NO2 and SO2) inside and outside with windows open and windows closed, and for some reason closed windows do provide limited protection against them. Nobody really understands why AFAIK, it shouldn't work that way since they're mixed with air in a gaseous mixture from which they can't be filtered out without a specialized chemical filter, but it does help.
- agwa 1y ago
  We should clarify what type of sensors we're talking about. It seems to be easier to find accurate inexpensive sensors for particulate matter (PM) and CO2 than it is for VOCs.
- mschuster91 1y ago
  > and with a purifier the difference in particulate levels can run into 100× or more during winter No surprise. A lot of homes are still being heated by combustion. Gas heating is relatively clean if the burners are properly maintained, oil burners are a hit and miss, but everything else... wood pellets are often declared as the "green" alternative, but that's only valid for CO2 (and even there, the actual benefit for the climate is massively debated) - these things spew an awful lot of particulate emissions, brick-wood ovens are even worse, especially when people illegally throw in too humid firewood or, worse, garbage that has no business being incinerated outside of an industrial high temperature facility with proper exhaust stack treatments. Unfortunately, as you say, in many parts of the world people are too poor to afford proper heating fuel sources, and it's costing them and their countries so much productivity and money in the long run... and in developed countries, there still are a sizable amount of people who have no idea how to properly heat their ovens, how to prepare their firewood or that just outright skirt garbage disposal fees. Jörg Kachelmann, founder of the weather service Meteomedia, has extensively written about that topic in the past [1] and keeps ranting on social media about it under #holzofengate. [1] https://www.t-online.de/nachrichten/panorama/id_84671908/kachelmanns-donnerwetter-feinstaub-aus-holzoefen-die-gemuetlichen-dementoren.html https://www.t-online.de/nachrichten/panorama/id_84671908/kac...

seper8 1y ago

Crack a window open (Except if you live in a city)

cameronh90 1y ago

The challenge with opening the window isn't even the cost - which is substantial - from about £250/month to £400/month if I have my windows open even a little bit. The bigger challenge is with my windows open, my heating just can't even keep up! It'll be maxed out and only 18c. I do the German-style luften twice a day, but if our interiors are just absorbing the compounds and releasing it when the windows are shut, then that's not even going to help much.

b112 1y ago
Get a heat recovery exchanger. https://natural-resources.canada.ca/stories/spotlight-energy-efficiency/what-s-heatenergy-recovery-ventilator-need-one https://natural-resources.canada.ca/stories/spotlight-energy...
- cameronh90 1y ago
  Indeed, but a traditional MVHR would require ductwork which isn't common in the UK and often there isn't really any space to route it. I have been investigating easier to retrofit decentralised MVHR systems such as the Prana Recuperator, Ventaxia Tempra and the Blauberg Vento. They can be noisy (not a problem for me, I don't mind noise) and quite expensive as you have to fit a number of units in different rooms, but still easier than retrofitting ducting.
- mrktf 1y ago
  It is called recuperator. If it is possible to retrofit i suggest to use mounted in attic (it will be silent). Otherwise, if you want higher quality not and these `breathing` types the box will have similar size like air conditioner (search: mitsubishi vl-100eu5-e)
- esperent 1y ago
  Good advice if you can do it, but this isn't possible for most people, for example if you're renting or you're in an apartment.
- whatevaa 1y ago
  It's not something you just add. It's a capital renovation. Requires ducting. Tons of homes don't even have ducting.

coder543 1y ago

Outside air isn’t a panacea. There is often plenty of pollution right outside your window unless you live on an idyllic beachfront property. The humidity level outside is also rarely what you want in your home, whether it is too high or too low. Much better than cracking a window is the use of ERVs (energy recovery ventilators) and air filters on the incoming air. An ERV is a fairly simple device that exchanges air with the outside while mitigating the loss of energy and humidity. Any modern home build likely has an ERV as part of the design, but it’s not like they can’t be retrofitted, and I’ve even seen some DIY-friendly window unit ERVs (but I’ve never heard if those are any good).

Hnrobert42 1y ago
I live in an apartment in Washington DC. Opening a window reduces CO2 and VOCs. An ERV is great if you can afford it, but cracking the window is still quite reasonable.
- coder543 1y ago
  CO2 and VOCs, but what about PM2.5 and PM10? What about pollen? What about humidity control? Cracking a window is also costly, since it directly raises your heating and cooling bills. It's just an "invisible" cost that's easy for some people to ignore since it's hard to directly measure. An ERV pays for itself over time, so it's more a question of whether you can afford to just crack a window? Living in an apartment makes this difficult because your landlord may not let you improve this situation, but just ignoring the cost of opening a window doesn't make the cost go away.
  - encom 1y ago
    Don't leave your windows open all the time. Open them for 5-10 minutes at least once a day. Heating air is cheap, it's heating all the other mass in your home that's hard, so don't let it cool down. If you live somewhere uninhabitable like Texas, change heating for cooling.
    - 1y ago

deleted 1y ago

[deleted]

jbd0 1y ago

I built a window vent with a variable-speed computer fan and an esp8266 that communicates with a CO2 monitor and raises the speed when the CO2 gets too high. I have a very fine mesh on the window screen that's designed to filter out pollen and dust. It works really well. I usually only turn it on at night, because that's when my wife and I are both in the room and the CO2 can really build up.

J_Shelby_J 1y ago
I use an ikea air filter that just so happens to fit perfectly in the window + a smart outlet and co2 sensors. I’d like to do a custom build like you so the fan speeds are variable.

nobodyandproud 1y ago

Good advice on the CO2 monitor. Cheap and surprisingly effective. I haven't considered the VOC--any recommendations? As an aside, I open up my window, but sometimes smokers decide to take a break outside and...well. Other times, I have neighbors barbecuing. If I don't shut the windows quickly I've just replaced stale and somewhat harmful air with oxygenated and definitely harmful air.

twothamendment 1y ago
I've been using the Awair Element for years. It helped me decide to install an air exchanger an to swap the gas range with induction. Bonus, it has a local API for pulling data. I have a purple air sensor outside. One day I'll get around to making the air exchanger smart enough to turn off when the smoke from fires makes the air outside worse than inside, it turn off the air exchanger when inside air is good enough, etc.
prewett 1y ago
I've been happy with the AirGradient One, which does have VOC measurement, as well as CO2, and PPM 2.5. It seems that VOC on the hardware side is relative, so the amount is just compared to a baseline (last 24 hours in the case of the AirGradient One). Also, VOCs are everywhere, but not necessarily harmful: cooking will spike your VOCs, but that's very different than having a can of varnish open.

modeless 1y ago

Every home should have a heat recovery ventilation system. It gives you fresh outside air in the whole home, but filtered to remove PM2.5 and without the inefficiency.

cryptonector 1y ago
Can you say more? Maybe link to a useful page or product(s)?
- throawayonthe 1y ago
  https://en.wikipedia.org/wiki/Heat_recovery_ventilation https://en.wikipedia.org/wiki/Heat_recovery_ventilation
IncreasePosts 1y ago
Many new builds will, especially in places with required efficiency standards, but the average house in the US is 40 years old. And leaky as hell.

lupusreal 1y ago

> Yes, this means your heating and cooling bill will be a bit higher. Not even necessarily. People these days are accustomed to keeping their homes at comfortable T-shirt temps even in the dead of winter, but if you dress appropriately for the season you can drop your indoor temperatures 20F or more from what people normally set the thermostat to while still maintaining a safe margin to keep your pipes from freezing.

jerryjerrygeri 1y ago

Yeah thermodynamics though; generation of electricity for that extra heat or cold waste heats up planet.