Companies that have facilities which use refrigeration and air-conditioning systems or heating, ventilation and air conditioning systems have to measure changes which are imposed upon them due to greenhouse gas emissions. Additionality is a measure which compares the level of emissions prior to implementation with the levels after a greenhouse gas reduction project has been introduced.

Additionality metrics are part of a monitoring and verification plan, which is set up when a greenhouse gas reduction project is underway. The metrics explain when and how the plan would be implemented as well as who is responsible for conducting the process. As this is a complicated area, software has been developed by specialists to simplify the procedure.

Project specific assessments are implemented by facilities that use refrigerant. Projected greenhouse gas reduction levels are calculated on an individual basis, by creating a baseline of levels to commence. Once a project is in place, a emission levels are compared to the baseline and the actual greenhouse gas emission reduction is calculated.

Specific industries have specific performance assessments, as used to determine additionality. For example, heating, ventilation and air-conditioning system manufacturers or refrigeration and air-conditioning system manufacturers may measure performance improvements as compared to existing standards. This will apply for particular appliances or processes in relation to the reduction of greenhouse gas.

When it comes to slowing global climate change caused by greenhouse gas emissions, additionality plays a key role in determining the effectiveness of a reduction project. Greenhouse gas offset projects are being conducted across all industry sectors. Some examples are renewable energy efforts, methane capture and recovery in landfills, and reforestation.

For businesses, it is important from an accounting standpoint to show the benefits of a greenhouse gas reduction program. In order for it to be a true emissions reduction, additionality criteria must be met. Ongoing monitoring and verification are key components to ensure actual reductions are real and have long-term sustainability. For facilities developing methods to reduce their use of refrigerant gas, automation of monitoring and tracking exists through software and web based applications developed by software providers who specialize in this area.

An important part of an additionality equation involves an examination of the permanency of the project. Risk factors must also be determined, leakage issues addressed and proper accounting maintained through verification and monitoring.

Within the United States and overseas, the debate continues regarding funding. Whether or not funds should be made available to companies to enact programs aimed at reducing greenhouse gas emissions is under question. As a benchmarking system for certain industries is under development, the determination of funding would require feedback through additionality to show that the project went beyond regular business activities. As an example, funding would not be made available if the project would have occurred anyway due to conventional business improvement.