Many homey-connected devices have temperature sensors, so one can quickly assemble a good idea about the temperature across the house. However, I found out there are significant differences to the usability to put different sensors to control flows (accuracy and precision of readout). The three images attached show graphs of the temperature profile in different rooms (with slightly different temperatures but a similar peak) during a sunny episode. Our netatmo room thermostat shows a precision of 0.1 degree steps, and appears to be very stable, it is accurate. The netatmo radiator valve is also very stable, but only shows 0.5 degree increments, a relatively low precision. The third graph is from a Hue presence sensor, which presents values in 2 decimal digits (very high precision) but appears to make roughly 0,25 degree steps and the readings are noisy (low accuracy).
Does anyone know other devices that give stable readings and 0.1 degree or better precision and are not off-the-charts for their costs?
This is quite a large variation between devices. Are the placed in the same place?
I haven’t seen such a variation on more or less the same spot between my devices.
Apart from that, where do you need a accuracy of less than 0,5 degrees for?
@rwwh Here are some devices that I’m using. Similar to you they are in different rooms and their readings differs from device to device. Keep in minds that Homey by itself also average the numbers in their Insights for older data.
Switchbot Hub 2 and SwitchBot Indoor/Outdoor Thermo-Hygrometer are both similar to your Netatmo thermostatic valves, a bit better but they increment by 0.2:
Thanks. I’m not worried about the differences in the readings: these devices are in different places in my apartment, so that can be expected: bedroom and guest room can be cooler than the living. And if there would be a consistent “misreading” I can easily compensate for that.
The reason why I want better than 0.5 degrees precision is because I am using temperature sensors in the house in control flows for the heating of the (well isolated) apartment with a heat pump, keeping temperature as stable as possible. During a cold night if I would switch off the heater the temperature in the living would drop between 0.1 and 0.2 degrees per hour, and that is also the usual heating rate. So for a reasonable control, I’d like to be able to see those differences: e.g. switch the heater off when the temperature reading goes from 20.4 to 20.5 and back on when it goes from 20.1 to 20.0. That is better than having a single 0.5 degree jump in a temperature reading and base the switching off/on the heater on that: off when it goes from 20.0 to 20.5 and on when it goes from 20.5 to 20.0 gives very little control over the hysteresis.
Homey seems to support Danfoss Ally room sensor. I bet that has accurate readings since Danfoss Ally Gateway is using that sensor to get accurate and frequent readings.
It’s not cheap though and I don’t have it myself so I can’t say how it works. I would just imagine it would fulfill your needs, but don’t take my word for it.
