Using a whole-house meter has helped me monitor progress in reducing electrical loads. When I first installed the meter, the typical load with everything off in the house was 500 watts. My previous house with everything off was about 800 watts. By systematically getting rid of phantom loads, the typical load with everything off was reduced to below 100 watts. That is a over a 400 watts saving x 24 hours/day = 9.6 kwh/day. With rates arround $.10/kwh that saves about $1 a day. But for me, this reduction meant I saved about $25,000 in PV in order to be net zero energy. Eliminating phantom loads is a big deal.

Currently I use two meters. One meter is hooked to the grid and the other to the solar panels. This way it is easy to see solar production and grid usage.