I think $10 is too low an estimate.
An AirFanta 3Pro on low (2) is 5W, which is $10 on average (but more like $15 in high $/kWh places like MA and CA).
alt Hacker News
An AirFanta 3Pro on low (2) is 5W, which is $10 on average (but more like $15 in high $/kWh places like MA and CA).