Hi,
I’m experiencing much too high humidity sensor values with Ikea Vindstyrka in comparison to a dump humidity sensor. First search engine hit was this, which describes my problem exactly (on the wrong platform). Are there more users observing this? Or do I have an especially inaccurate version and yours is working fine?
For me it’s not an suitable option to transform the value afterwards. For that I could have bought a cheaper version without a display.
Too high for a dump one? Guess first thing todo is consult the data sheets of both devices to get an idea what they promise at first 
In case they don’t even tell it might be already a bad sign (expecting like +/-10% or more inaccuracy) - still you could check the sensors/chip’s them self inside the device to still hunt down hard facts 
Hello,
I am having the exact same problem. In my case it is 8% higher than 2 other sensors. I have tried changing the device at Ikea but I got the same pattern with both devices.
Shame …
2 years later I found the same problem with this Ikea sensor: +10% Humidity comparing to other sensors in my home. Since I didn’t find a way to set it right (on the device itself, not in HA), I sned it back and plan to use DHT22 with Arduino. I am still interested if someone find a solution to modify the displayed value for humidity on the sensor dusplay.
And might still be the most correct one…
If +/- 5% accuracy is not enough for you, DHT22 is likely not the best choice.
Which others/What specifications? As relative humidity is temperature depend it would also be necessery to read the tempartues at the same time 
I would skip both. DHT22 when not getting your hands on original ones are extrodianry bad. And arduino doesn’t feature a network interface, a $2 esp32-c3 (supermini) should be superior in every aspect (best obviously running esphome) 
Thank you for reply and advices. My comparison was made in the same time: dehumidifier working with sensor and display, another independent device for temp and humidity measurement indoor + outdoor and new Ikea Vindstyrka. All sensors show 57-59, Ikea show 69 and move just a little bit less even when position in the front of dehumidifier.
I already have several Arduino boards, Ethernet and WiFi shields and few DHT22, for this reason I plan to use them. I also have one BME280, and seems to be more interesting option - I saw the comparison proposed by orange-assistant, thanks.
For DHT it may be possible to adjust the received data on Arduino board.
