RMI, formerly Rocky Mountain Institute, is having a real impact on the residential building sector these days—first, with the introduction of HomebuildersCAN and now with the just-released Green Upgrade Calculator. According to Ryan Shea, manager of carbon-free buildings for RMI, “Energy professionals—contractors, advisors, and analysts—have struggled to provide a better answer than, ‘It depends,’ to common homeowner questions like, ‘How cost-effective is this specific home or vehicle upgrade?’ and ‘Which upgrade reduces the most carbon pollution?’.”

The Green Upgrade Calculator does indeed give a better answer. You can test things like weatherization upgrades or the addition of rooftop solar, battery storage, heat pumps, heat pump water heaters, and induction cooktops. The results tell you the carbon reductions in tons—both upfront and operating—as well as the upfront and annual financial savings. Notwithstanding the illustration with its solar panels and battery storage, it’s not a “green gizmo” approach where you just add more stuff and get greener; it evaluates the effectiveness of each choice.

The tool at a glance

The Green Upgrade Calculator was developed by RMI and seven partners: Abode Energy Management, Arcadia, Electrification Coalition, New Buildings Institute, Northeast Energy Efficiency Partnerships, Pacific Northwest National Laboratory, and Solar United Neighbors.

The calculator is like an onion; there are so many layers that you can keep peeling. To start, you can enter basic data and let the defaults do the work to get a quick-and-dirty answer. The defaults are based on information from the Energy Information Agency and numerous databases, labs, and RSMeans Data.

Get past the defaults, and you can drill down to much finer details. In the weatherization category, for example, you can enter detail on air changes, insulation, windows, and glazing. As an example of the level of detail and complexity, the FAQ…