I did 2 approx. 8 hour measurements now.
1 nodemcu 1.0 on a 600 mA adapter.
The nodemcu holds 2 ds18b20 temperature sensors (vreezer & cooler) and a PIR motion sensor.
During 7 hours the constant power consumption was 0.8 Watts.
On a yearly basis that is ≈ 7 kWh for 0,20 Euro per kWh (Dutch rates) ≈ 1,40 Euros.
1 nodemcu 0.9 on a 500 mA adapter for 9 hours.
This nodemcu holds one Keyes relais to control my central heating.
relay off ≈ 0,7 W
relay on ≈ 1,2 W
Extrapolated and calculated with the “night off” period and a normal day on/of schedule at 1-4 °C outside temperature, I come to an average of 0.9 W.
On a yearly basis that would be ≈ 1,75 Euro (Dutch rates).
All not very much and nothing to worry about.
@Rene-Arts : I know that the 100 mA is on the 230 V side. That’s why I calculated the 230 V * 100 mA = 23W. Fortunately it is using far less.
I have about 15 loaders in my house: for my esp8266 nodemcus, my banapi, my pimatic RPi3, my 2 RPi B+ (media streamers; not always on), our phones, my 2 photo cameras, and some more.
All have slightly different specs typed on the adapter. Some require less mA on the 230 V side while delivering more output on the 5V side than others. All my adapters are good quality adapters as I also know from 2 cheap “Action” adapters that they produce a very high annoying beep.
Now see what my RPi3 does simultaniously running pimatic and my video monitoring system motion using a USB cam also doing subsequent video conversion on 720p captured content and rsyncing that to my webserver.