When I bought a good CO2 monitor I have discovered how difficult it is to keep CO2 levels down in an apartment that does not have two permanently open windows on two sides of the building.
For example, the most surprising thing I have discovered is that just keeping the window open IS NOT ENOUGH.
In my location, it is common for the outside temperature to be lower than room temperature at night but higher than room temperature during the day.
There obviously is some time in the morning / evening where the temperature inside and outside is exactly the same. At this time, the air stops flowing in and out of the apartment, even if you have the windows wide open. The CO2 starts accumulating at a very high rate pretty much as if the windows were closed.
I was very surprised by the graph showing large spikes up to 1500ppm in the morning while I was asleep. I was suspecting it is causing me to feel poorly in the morning and I started to feel much better when I started to sleep in a room with also the door open so that the air can freely flow through entire apartment.
I don't live in an apartment but I have a basement and I experience the same thing. My CO2 levels constantly hover around 500ppm. Opening windows will clear out CO2 if it gets to critical levels but has diminishing returns at the 500ppm level. I suspect this is because CO2 is a heavy gas that often sits near the floor. My next experiment is to install a small fan near the floor and run it 24/7 to see if I can "pump out" the CO2 while the split units I have are running.
Technically, any level of CO2 causes detriment. Even our ambient level is higher than some decades ago and apparently it is possible to measure the effect on us (mostly related to nervous system).
Personally, I can't discern any difference below 600 any way I tried to measure it.
I carry my Aranet4 with me and in some apartments of my friends and family it is normal for CO2 to not go below 2000ppm in winter. So you are doing pretty well.
I think this is incorrect. You may be thinking about PM2.5 levels of which there are no safe level, any amount is harmful. Similar for CO. But a certain non-zero amount of CO2 is actually required.
a) Good ones are expensive, and the consumer grade ones are valuable mostly for trends rather than precise readings.
b) They do occasionally require re-calibration. Meaning, leave it outside for 24 hours. The ones I have experience with expect an occasional return to atmospheric baseline, but if that never happens naturally - which never does in my apartment - they tend to drift.
c) Your basement might have amazing circulation. I have an air pump (it's a big radon fan) pumping in fresh air to my apartment any time CO2 rises about 700ppm, and the exhaust fan pulling air out as well. In theory, my circulation is quite good. However, even with all that the CO2 is quite high (700-1000ppm) while we're home.
You should consider an energy recovery ventilator. It blows in fresh outside air but it uses exhausted inside air to bring it up to the temperature of your home.
And this will work in a the apartment that OP is living in? Because that sounds like it might involve some invasive installation. If it's just a box one can plug in, maybe a vent hose, that would be great.
I'm surprised that there are no portable ERVs similar to portable AC units that just vent out a window. I have a small ERV in my shed/office that uses a single outdoor and indoor vent for combined intake/exhaust. (ie minimal ducting)
I’ve seen them in a form factor that resembles a short, shallow window air conditioner that you just close your window on top of and optionally lock into place with screws.
Some ERVs come in the shape of a cylinder, about 10cm x 30cm for use in apartments.
Yes, installation requires cutting a hole in the wall, but it is doable.
Yep. You are right. This is my main problem here -- not only the inside installation is extremely invasive. But the local laws basically prevent me from being able to make the large holes in the wall needed to pass the massive amounts of air.
Central Europe. Humidity varies widely depending on weather and temperature, typically ranging from about 40% during the day and 80-90% in the morning on a nice day. Higher on a rainy day.
My plan is to have a heat exchanger to help with this, which will also improve the situation much more on very hot and very cold days when I can't keep windows wide open.
Heat exchanger blows outside air in and inside air out. Both air streams are flowing through the box in opposite directions, without mixing, so that outgoing air heats up and gets cooled by incoming air (assuming outside is colder than inside). These devices can be extremely efficient as they can recover something like 80-90% of energy.
In my case I am not necessarily looking to save up more energy, I am interested in being able to ventilate the apartment better without breaking the bank on energy.
But if your nights are slightly colder and days slightly hotter and humidity is so low then why be so complicated? You don't need heating, don't need AC... unlike tropics with constant +30 and 90% humidity or snowy places where it's -30 in winter, seems like you can just ventilate
See this cool chart btw: https://drajmarsh.bitbucket.io/psychro-chart2d.html (pick your place, select comfort overlay -> Givoni and it will show what you need to be in comfort zone in a given month based on temperatures and humidity)
Because we have winters? Like -20C? And then just opening the window to keep the apartment well ventilated is no longer very practical when you ask for a latte but get frappe if you don't drink it immediately...
Oh, I thought the weather you described was year round... Yeah heat exchanger sounds really cool. From Wikipedia, are they those big industrial things for houses? or can you fit a flat with it, like a window unit or something?
For example, the most surprising thing I have discovered is that just keeping the window open IS NOT ENOUGH.
In my location, it is common for the outside temperature to be lower than room temperature at night but higher than room temperature during the day.
There obviously is some time in the morning / evening where the temperature inside and outside is exactly the same. At this time, the air stops flowing in and out of the apartment, even if you have the windows wide open. The CO2 starts accumulating at a very high rate pretty much as if the windows were closed.
I was very surprised by the graph showing large spikes up to 1500ppm in the morning while I was asleep. I was suspecting it is causing me to feel poorly in the morning and I started to feel much better when I started to sleep in a room with also the door open so that the air can freely flow through entire apartment.