The HeatMeter was developed by a couple of MIT grads and is designed to monitor fossil fuel use at the appliance. They are trying to raise money through Kickstarter to ramp up their production line. This could be the answer to tracking pre/post improvement fossil fuel consumption. Check it out.
(BTW, other than being MIT alumni, I have no affiliation with these people or this company but I did make a pledge so I can get a couple of these installed in my house.)
http://www.kickstarter.com/projects/474 ... ave-energy
HeatMeter: Stay Informed, Save Energy