Just bought a mains power/energy monitor (I'll be using it to try building a low-power home server), and here are the results on running the R2H off the mains.
Browsing/downloading using the wireless connection:
- screen off: 15-16W
- low brightness: 15-16W
- half brightness: 17-18W
- full brightness: 18-19W
- pretty much the same results as above.
- ~1-2W higher power consumption than above.
This means in the end the power consumption of the Asus R2H is lower than 0.02kWh in most scenarios.
As a comparison, my XPC Shuttle desktop PC (P4 HT Prescott 3 GHz, 1 GB RAM, Radeon 9600XT, 200 GB HDD) draws ~85W when idle and ~133W under load (Super PI) - the measurements are for the PC alone, monitor not included.