One of the key challenges in building decarbonization is not just identifying what interventions to implement, but determining when to implement them. Retrofit decisions rarely happen all at once; they are shaped by tenant lease lengths and turnover, capital planning cycles, equipment lifespans, and regulatory timelines. The Decarbonization Over Time feature in Carbon Signal allows you to create realistic, phased implementation plans that reflect these real-world constraints.
Decarbonization Over Time takes the results of the baseline building and applies selected interventions across a multi-year timeline. The result is a dynamic emissions reduction forecast that can be used for capital budgeting, investment planning, and communicating long-term decarbonization goals. Rather than a single static intervention package, this feature supports iterative planning.
Creating a Reduction Pathway
By default, each intervention is scheduled for implementation one year after the baseline data year.
To modify when an intervention is implemented, navigate to the Applied Interventions table listing each intervention along with its estimated emissions reduction, implementation year, and capex cost. Click the Edit icon next to the intervention you want to update.
A pop-up will appear where you can change the Implementation Year—this must be a year between 2020 and 2050.
After making your selection, click Save. The Reduction Pathway chart will then refresh automatically to reflect the change, showing the updated carbon reduction occurring in the selected year. This allows you to quickly adjust your timeline and see how different intervention schedules affect your overall emissions trajectory.
In addition to tracking emissions reductions, the Decarbonization Over Time feature is designed to support capital planning by visualizing the estimated capital expenditures (capex) of interventions over time. A bar chart below the Applied Interventions table displays the CapEx costs for each intervention, organized by their specified year of implementation. This helps users align retrofit planning with annual budget cycles and investment timelines.
The chart can also be toggled to show cumulative capital costs year over year, providing a clear view of total spending over the planning horizon.
Understanding the Interaction Between Building Interventions
It’s easy to assume that if one intervention saves energy, and another does too, you can just add the two together. But buildings don’t work that way. When you make one change—like improving insulation—it can affect how much of a difference another change—like replacing the heating system—will make. Since better insulation means the building needs less heat, the new heating system won’t save as much as it would have on its own. These overlapping effects mean that doing multiple upgrades doesn’t always equal the total of their individual savings.
Carbon Signal takes this into account in the Decarbonization Over Time tool. It applies each intervention one after the other and updates the impact along the way. That way, the savings shown are more accurate and avoid counting the same benefits twice.