Power consumption and Cost saving of Using Ooma (revised)

After awhile, I observed that this Ooma + router consume less power when the temperature is lower.  In the previous blog, I said the average power when its idling is 27 W @ 25 C, but in the early morning when temperature is lower (at about 20 C), the idling power is only 14 W and 17 W when the handset is off-hook.