Deemed savings refers to using equations or factors to calculate resource consumption savings from a range of actions.
The calculations are developed from a set of assumptions that should reflect an average scenario for the action or behaviour.
Ecological and carbon footprint calculators use deemed savings to calculate changes to footprints.
The Victorian Government Black Balloon campaign is also a good example of deemed savings.
An example of a deemed saving
|Electricity reduction from changing from incandescent to compact fluorescent light globe||2970 black balloons (50g of CO2e- per black balloon)||75W incandescent replaced with 15W CFL, on for 5h/day|
For examples of a deemed savings calculations table, click here. (TO BE SOURCED FROM SV )
The Australian National Greenhouse Factors can be use to calculate deemed greenhouse gas emissions savings for a range of actions, for example savings from waste or energy.
Examples of projects that have used deemed savings
|1-2-3 Campaign Against Global Warming|
|Participants were asked to commit to three actions 1) reduce their household thermostats by 1 degree in the heating season; 2) reduce their driving speeds by 2 miles per hour from the speed they'd normally drive when traveling 60 m.p.h. or more; and 3) replace 3 regular light bulbs used extensively at home with compact fluorescents. These three actions estimated to reduce carbon dioxide generation by 1,300 pounds per year. Evaluations based on number of pledges made, and follow up survey to see if pledge had been followed through. Estimated annual CO2 reduction by approximately 580,000 pounds|
|Greenhouse Games Workplace Challenge|
|The Greenhouse Games Workplace Challenge was an initiative of Sustainability Victoria that actively engaged 822 households in its pilot phase.
The project consisted of an 8-week online challenge that required households to commit to undertaking self-selected behaviours, based on a preliminary household survey.
Combined, participants reported completing 25,436 individual actions ranging from 953 one off changes to 24,483 daily behaviour change actions.
Assuming a best-case scenario that encompasses truthful reporting of actions and no drop-off in behaviours,the project achieved a total of 1394.51 annualised tonnes of GHG abatement, and over 15 million litres of water saved annually.
Source: National Centre for Sustainability and Sustainability Victoria
Pros and Cons of Deemed Savings
|Provides an estimate of resource savings from individual or grouped behaviours||Subjective estimate of calculations|
|Provides context to changes in resource consumption patters||Potential for unreliability based on untrue answers, or inaccuracy of assumptions for calculations|
|Overcomes constraints of collecting metering data||May not capture unintended consequences|