More likely is that Jeff's house is poorly insulated relative to his neighbors. Or that the "average" presented is extremely skewed and not actually representative. (Is Jeff's house actually <1200 sq ft?) It might be interesting to see how many households get reports indicating that they are "above average".
It doesn't matter how low energy your servers are they are still servers than most people don't have.
Jeff's recent server build (which I believe is going to a colo and not sitting in his house anyway), uses 31 watts at idle and 87 watts at full load. Assuming the middle is typical (and this is likely a serious overestimate), you're looking at 59 watts, or 10kWh/week. You could offset this with a more efficient furnace, or better insulation. You could also more than offset this by hanging 3 loads of clothes per week instead of putting them through an electric dryer (~5000 watt).