I guess the problem is with the price of the sensors. Just look how expensive the Aranet 4 home shown in article is. There are worse devices for less like the IKEA alpstuga. I also don’t know how much electricity they pull.
I would hesitate to say the IKEA is worse. Inside the IKEA is a reputable Sensirion all in one sensor module. It's much cheaper and smaller because the CO2 sensor in it is using different (newer) technology that only released a few years ago from Sensirion.
(Upd: the IKEA does have lower accuracy, with ±100 ppm instead of ±30 ppm. From the SEN63C datasheet)
Worse specs? Sure. Worse value? I don't think so. Worse accuracy? Perhaps not either.
A price of 30 EUR makes this sensor really easy to pick up. For the same price as one Aranet (~180 EUR) the typical household can place a sensor in every room of the house. Which provides far more accurate readings for the whole house than just one high-end sensor in one room.
I have one IKEA Apstuga on my desk, sitting right next to a good CO2 monitor.
Since Apstuga uses worse approach (heat) rather than light as the good sensors, it diviates around +/- 100 ppm. For example the correct CO2 is 610 ppm and IKEA's sensor shows 552 ppm with is reasonably close. So the trend will be correct and the values will not be.
But when it goes over the safe limit it should be enough to decide to ventilate.
No, it is crap. Yes, it is Sensirion, but it uses a thermal conductivity sensor, which is a very indirect method of measuring CO2. One part of the sensor emits heat and the other senses it and the idea is that heat transfer changes with different CO2 concentrations. However, a lot of other factors influence this as well, such as ambient temperature/humidity (which is why the sensor incorporates measurements from an SHT sensor), but also gas mixture, etc. You only get good readings at lab conditions. Even below 1000 ppm, I would often see readings that are 300 ppm from more expensive, known-good CO2 meters.
If you want a CO2 meter on the cheap, either wire up an optical NDIR sensor like the SenseAir S88 (22 Euro) up to an esp32, which is possibly the best sensor you can get for the money (slightly cheaper version of the sensor that the AraNet4 uses). Or if you want something standalone with a display, get the SwitchBot Meter Pro CO2 for ~50 Euro, which uses a photoacoustic NDIR, but is still miles better than the sensor in the ALPSTUGA. Can also be hooked up with HA through an ESPHome BLE proxy or with the SwitchBot Hub.
You can find a comparison of the IKEA sensor with other affordable sensors here:
(Upd: the IKEA does have lower accuracy, with ±100 ppm instead of ±30 ppm. From the SEN63C datasheet)
You forget to mention that it is ±100ppm plus ±10% of the ambient ppm, which makes a big difference. At 1000ppm it's ±(100ppm + 0.10*1000) = 200ppm and that's only in an environment with 25C, 50% RH, and 1013 mbar. So, that does not tell you much, given that thermal conductivity is very sensitive to environmental factors.
No, it's not. You generally want to ventilate an office when you reach 1000ppm, but then the IKEA will often warn you already at 700ppm. 700ppm is fine.
"Generally" is a vibe measurement to begin with. You won't notice any difference at all between 700ppm and 1000ppm. It's once you start hitting 2000ppm you are getting noticeable brain fog.
Had bad ventilation in my old apartment (built 1888) so got a co2 monitor. Started feeling the effect at 1100-1300ppm, so would open it in home assistant and check, never below and never above really. During winter when it was -10 so couldn't keep the window open all the time.
I disagree. I feel a very steady and progressive deterioration starting at 600 ppm. It becomes significant at 800 ppm. The studies back up the latter threshold.
Have you looked at the prices of meeting room furniture? A $200 meter is not a significant cost measured against what it costs to furnish the room in the first place. It only becomes significant is you treat it as a line item disconnected from the room it's in
There are good $50 Euro meters. Besides that, I am not sure if that is true, at my wife's workplace, they put high-end CO2 meters in every larger room where multiple people meet. Admittedly, this was during COVID, so a lot of organizations were using CO2 levels as a proxy for finding whether a room was properly ventilated.
Presumably there is still the need to ventilate. So the concentration can also be measured more centrally. That is how the mechanical ventilation unit in my house works. For both humidity and CO2.
I got the ikea sensor, I’d say it’s way more accurate than you need for personal use. I wouldn’t use it as a scientific instrument but it’s well good enough to see if the room is ventilated enough.
I was shocked to see just how fast CO2 climbs while in a room, and how just opening the window just a crack was enough to restore the room to baseline co2.
The thing runs on usb 5v so the power consumption is negligible. It also plugs in to home assistant great.
I have HA send me a notification to ventilate my office when the air reaches 1000ppm CO2. The IKEA ALPSTUGA is often off by 300ppm even under 1000ppm. If I'd use it, I'd be getting notifications at 700ppm.
It is a thermal conductivity sensor, which is a very indirect way of measuring CO2 and is very sensitive to environment factors. You only get somewhat good readings in lab conditions.
Don't by the ALPSTUGA for anything but very rough trends, there are much better affordable options.
I notice that thinking becomes less clear when going above 1000ppm, so I let HA send a notification at 1000ppm. With ALPSTUGA it would send already at 700ppm. By the way, above 1000 the divergences become even larger due to the inaccuracy also being 10% of the ambient CO2 concentration (in optimal circumstances, probably larger IRL). So, suppose you want to be notified at 2000 ppm, the IKEA sensor might already do so at 1500 or 1600 ppm and it continuously drifts, so it's not like you can use a particular offset.
Besides that, what's the point? There are much better meters in a similar price class. As an additional benefit, they can last months or up to a year on two AA batteries.
In some situations it means opening a windows, with big temperature drops when it is cold outside.
At any rate, this is really a weird discussion, because you can get far more accurate meters at similar price points. Why waste your money on a much worse meter?
I don't think power use is the issue. I have this cheap CO2 sensor: https://www.domadoo.fr/en/devices/5882-heiman-zigbee-air-qua...
which draws 0.5W. This includes thermometer and humidity sensor, Zigbee transmission, and acting as a Zigbee router, but it gives us an upper bound.
It also measures continuously (picks up someone breathing on it within 10s), which is overkill. A phone could measure CO2 levels once every 10 minutes which would average under 0.01W, so that would work.
However, this assumes the sensor would fit in a smartphone, which is not a given. And these things need air flow. And they also wouldn't work while the phone is in a bag or a pocket.
>A phone could measure CO2 levels once every 10 minutes which would average under 0.01W, so that would work.
Not sure about that, at least NDIR sensors have to be at certain elevated temperature to work and they do some preheating when you turn them on from standby.
So it's not possible to just measure less often as then energy would have to be spent on heating the sensor.
I've got a NDIR CO2 sensor about 6 weeks into a supposed 1 year battery life, still reporting 100% battery. Power use is very low since it only fires up the CO2 sensor every 30 mins.
I'm using a bunch of IKEA's "smart home" stuff, all via Zigbee+HA, works great. Look for the Zigbee icon on the package, and the pairing for Zigbee vs their own home controller might have slightly different pairing sequence on the device, otherwise it just seems to work.
They recently overhauled their lineup and replaced all Zigbee devices by Thread + Matter. Some of the new devices (mostly those who support TouchLink, e.g. some of the lights) have a secret pairing mode with which you can use them with Zigbee, but it's only a subset of the new products.
> They recently overhauled their lineup and replaced all Zigbee devices by Thread + Matter.
Uuh, seems not keeping up with social media finally backfired. That sounds horrible! So far IKEA been a great experience when it comes to HA+Zigbee stuff, and I started buying stuff relying on they'd keep just keeping up with that, really sad to hear they've changed course.
The "secret pairing mode" stuff sounds the same as currently/before though, but they only do so for a subset is new and hope they again change their mind.
Thread is significantly better. Zigbee relied on proprietary hubs and apps or hacky work arounds. Matter over thread devices don't need a brand specific hub or app. You can literally control the new ikea products direct from a modern iphone which includes a thread radio, no hub, server or app required.
If you already own the ikea hub, they secretly put thread radio in it which was just sitting unused in preparation for this range.
Yeah, I bought a bunch of INSPELNING smart plugs when they were clearing out the inventory. The new GRILLPLATS switches are more compact though, which is nice.
Ruuvi Air[1] seems to be close to the middle in both price and CO2 measurement accuracy between aranet4 and the IKEA device. I don't have personal experience with Ruuvi Air specifically, but have been using their cheaper Ruuvi Tags (that don't measure CO2) for temperature, humidity and air pressure measurement at home and office.
(Upd: the IKEA does have lower accuracy, with ±100 ppm instead of ±30 ppm. From the SEN63C datasheet)