With only five percent of the world's population, the U.S is contributing 25 percent1 of the total carbon dioxide produced in the world. An average American consumes 12,187KWh2 per year of electricity and emits 9.8 metric tons3 of CO2 per year. Residual carbon dioxide from residential sources like home electricity, water, gas, and oil consumption makes up an estimated 10%2 to this total. In our research group we are focused on measuring and motivating energy conservation behavior at the personal level. The ‘Just in Time Carbon Footprint’ project is an effort to study how informing occupants of the home about their energy expenditure and carbon footprint (measurement & calculation of CO2 emitted as part of daily life activities) in real-time might lead to energy conservation. In current work, we are using a facility called PlaceLab, which is a residential observational laboratory outfitted with hundreds of sensors such as electrical current flow, temperature, water flow, object motion, infrared person motion and an extensive audio-visual recording infrastructure permitting researchers to monitor almost every activity of subjects who live in the home. Currently we are analyzing data collected from a couple who lived in the PlaceLab for 13 weeks. Our preliminary research on electricity usage of the couple suggests that of the total electricity expenditure, as much as 40% could have been saved either using a combination of automation and computer-driven interventions that lead to behavior change. Our aim is to develop novel strategies for automation and just-in-time behavior modification systems that exploit ubiquitous computing (i.e., sensors placed in the environment and worn on the body). We then plan to test those algorithms and behavior change strategies to show proof of concept usability and viability in the PlaceLab.