REALIZE Zero Carbon Deep Energy Retrofit Case Study

This case study details the planned zero-carbon deep energy retrofit of Hano Homes, a 20-apartment affordable housing property in Boston, MA. The project aims to achieve Phius certification by implementing a superinsulated exterior shell, transitioning to all-electric mechanical systems, and installing a rooftop solar array to reach net-zero energy operations.

• The retrofit of Hano Homes is projected to reduce energy usage by 69 percent through electrification and energy efficiency, lowering the Energy Use Intensity (EUI) from 75.2 kBtu/sf to 23.2 kBtu/sf. This reduction is expected to cut greenhouse gas emissions by 50 percent based on current electricity supply.
• The building's envelope will be upgraded to a superinsulated skin, increasing wall thermal resistance from R-10 to R-36.8 and roof resistance from R-20 to R-59.1. The strategy includes 7/16 inch ZIP System Wall Sheathing as an air barrier and 8 inches of carbon-storing wood fiber insulation to eliminate embodied carbon emissions from renovation materials.
• The project will replace central gas boilers and water heaters with a decentralized all-electric system. This includes Minotair Pentacare V12 units—which combine a heat pump, air exchanger, dehumidifier, and HEPA filtration—and heat pump water heaters to eliminate all on-site gas consumption.
• A rooftop solar PV system estimated at 100–110 kW is intended to serve 100 percent of the building's energy load, resulting in a modeled EUI of 0 kBtu/sf and an estimated annual utility cost saving of $43,566.
• The anticipated hard construction cost for the deep energy retrofit is $3,039,995, which equates to $122 per square foot of floor area or $152,000 per apartment. The exterior insulated envelope assembly (wall and roof) accounts for $1,757,855 of this total.

APA

RMI (n.d.). REALIZE Zero Carbon Deep Energy Retrofit Case Study. https://rmi.org/app/uploads/2023/02/hano_homes_case_study.pdf

Chicago

RMI. REALIZE Zero Carbon Deep Energy Retrofit Case Study. n.d. https://rmi.org/app/uploads/2023/02/hano_homes_case_study.pdf.

Wikipedia

{{cite report |author=RMI |title=REALIZE Zero Carbon Deep Energy Retrofit Case Study |url=https://rmi.org/app/uploads/2023/02/hano_homes_case_study.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmindrealize, author = {{RMI}}, title = {{REALIZE Zero Carbon Deep Energy Retrofit Case Study}}, institution = {RMI}, url = {https://rmi.org/app/uploads/2023/02/hano_homes_case_study.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }