May 22, 2017

New Energy-Water Calculator Released

3d house blueprint 

Help Build It Green beta-test our new tool to estimate whole-building energy and water use to support utility allowances and zero net energy projects

Build It Green has developed a powerful new cloud-based modeling tool to quantify whole-building energy use, water use and greenhouse gas emissions for single family and multifamily residential projects.

The Energy-Water Calculator represents significant improvements over existing energy modeling tools, including updated algorithms and the ability to capture the energy savings and GHG emissions associated with water use. The Energy-Water Calculator is now ready for beta-testing by raters, energy consultants, builders, affordable housing developers, local government sustainability staff, and other professionals. Apply now to test the tool on your projects and provide BIG with valuable feedback as we finalize our tool for a full release.


Apply Now


6 Ways the Calculator Can Support Your Work

  • Utility allowance calculations: More accurately estimate utility allowances for multifamily tax credit projects, nationwide and in California. The Energy-Water Calculator offers significant improvements over the current California Utility Allowance Calculator (CUAC), with expanded functionality and updated algorithms.

  • ZNE analysis: Analyze a project’s Zero Net Energy potential to inform your design—including solar system sizing—or make recommendations for upgrades to existing buildings. As California and the nation move toward ZNE and low-carbon homes, builders and developers must calculate GHG emissions associated with their buildings, not just energy usage.

  • GreenPoint Rated certification: Identify inputs for renewable offsets and determine whether a project meets requirements to achieve GreenPoint Rated’s ZNE certification.

  • Project investment and financing: Attract investment and financing to your green projects; use the Calculator to showcase the energy, water, and GHG savings of your buildings.

  • Climate action planning: Calculate the greenhouse gas impacts of building projects’ energy and water consumption and take credit in your climate action plan.

  • Tenant energy cost estimates: Prospective renters or property owners can use the tool to estimate energy costs and savings of individual units, as well as the entire building.

Calculator Inputs and Outputs

The Calculator accounts for the following end uses:

  • Domestic hot water use and distribution

  • Lighting

  • Plug loads, including kitchen appliances, cooking, and laundry

  • Photovoltaics and solar thermal

    • The outputs include:

      • Energy (gas and electric) and domestic water usage, broken out by whole home/building and by unit type

      • Associated greenhouse gas emissions, broken out by whole home/building and by unit type

      • Energy and water saving opportunities


running faucetutility meter  thermostat

The calculations have been vetted by national and state experts. In addition, the California Energy Commission has reviewed the domestic hot water calculations. The Energy-Water Calculator was developed by Build It Green thanks to generous funding from the Energy Foundation. Questions about the Calculator? Contact This email address is being protected from spambots. You need JavaScript enabled to view it.