The first thing I did when we bought our new house was install a BlueLine Power Cost Monitor. It’s a simple wireless device that reads the electric meter in realtime, calculates the total cost of the current load based on your local kW/hour price. Then it relays the data it to a tiny screen elsewhere in your house. It’s been running since we bought the house (we still haven’t moved in).
I’m establishing a baseline of power usage for the empty house before appliances, servers, televisions — anything that gets plugged in — gets added. I’ll have a good idea as we start adding our life to the house, how much power each item uses.