We recently launched the WegoScore , the simplest distillation of a multifamily building's water and energy efficiency. In addition to energy use, we calculate a building's carbon footprint based on fuel choice and region. This graph shows how the Carbon WegoScores relate to the Energy WegoScores.
You can use the filters in the top panel to restrict which buildings are displayed. The visualization quickly reveals several insights:
- Carbon WegoScores do not track perfectly with on-site energy performance. Electrically-heated buildings (click to change the graph) generally receive lower Carbon WegoScores than their gas-heated peers with the same Energy Wegoscore. Both on-site performance and responsible fuel choice are important for energy management, but one does not necessarily imply the other.
- The fuel mix used to generate electricity significantly impacts Carbon WegoScores. Notice the buildings in the lower right corner with high Energy WegoScores but terrible Carbon WegoScores. Most of them are located in Midwestern grids, where the average amount of CO2 produced per unit energy is twice that of New England.
- The distribution of WegoScores is not flat. This is easy to see when you look at the marginal histograms on the top and right of graph. In essence, we don't have a quota for A's or F's; a great building gets a 100 no matter how many other 100's have been awarded. This also means there are a lot of buildings with the worst score of 1—these have the greatest savings potentials.
Each dot represents a single building (this graph shows a random sampling of buildings). When you hover over a dot, the lower panel shows a stacked bar graph, with each section corresponding to the energy use associated with one meter in the building. The meters are color-coded by fuel. This is useful to understand how each fuel contributes to a building's performance.
To derive a score, only buildings of the same building type and in the same climate zone are compared. Heating fuel is not taken into account, but you can filter by it in the top panel to gain intuition. Note how different the yearly usage bars are between mixed-climate low-rises and cold-climate low-rises. Buildings in the cold climate use much more energy, but are not handicapped because the owners cannot move the building to more temperate regions.
- Some features have been combined for aesthetics: e.g., the 'hot' and 'mixed' climate zones each combine two distinct zones, and the 'low-rise' building type combines multi-unit houses and larger low-rise buildings.
- The 'streaky' appearance of electrically-heated buildings derives from the specific CO2-conversion factors for each large geographic area.