One of the easier ways to demonstrate emissions reductions is to figure out how much energy you're saving due to the efficiency measure (these can easily be taken from the low-cost measures listed in the energy audit completed as a part of EAp1) and then multiply that amount by the appropriate emissions factor. You can find emissions factors for different fuel types and different parts of the country on the Energy Information Administration's website. Here’s an example:

Energy Efficient Action: Install CO2 sensors to reduce the ventilation during lower occupancy levels.GHG Emission Reduction: CO2 sensors reduce 10 metric tons of carbon emissions each year.