Large multifamily buildings with central heating systems that burn fossil fuels are among the hardest to decarbonize, but new systems such as window-mounted heat pumps, central air-to-water heat pumps, and “mono-block” mini heat pumps provide new options for decarbonizing these buildings. This report finds that window heat pumps generally have the lowest life-cycle capital and energy costs compared to various decarbonization options. 

This guide helps project teams establish strategic decarbonization plans for deep reductions in operational carbon emissions in existing buildings. It aids engineers and building professionals in hastening the transformation of the real-estate market toward a decarbonized state.

Retrofit navigator programs streamline the retrofit process, reach buildings and households that are often left out, and center the most critical community priorities. This document is a step-by-step guide for designing and implementing programs based on best practices. This slide-based report outlines the scope of need, problems with traditional retrofit programs, best practices for designing retrofit navigator programs, steps for designing and launching a retrofit navigator program, and case studies of successful existing programs from Philadelphia, Madison, and New York City.

Retrofitting buildings is a critical climate strategy, but we cannot ignore the embodied carbon impact of these retrofits. The production, transportation, and installation of materials all come with their own carbon footprints. This report provides data to support using low-carbon and carbon-storing materials in deep energy retrofits to reduce net emissions and transform buildings into climate assets. Lower embodied carbon options exist today and can be substituted for traditional materials.

Over half of California’s 3.2 million multifamily units were constructed before energy efficiency standards, resulting in poor performance and high greenhouse gas emissions. To achieve California’s greenhouse gas reduction goals, affordable multifamily housing must improve energy efficiency, reduce carbon emissions, and lower tenant utility bills while enhancing quality of life. Yet building owners face many challenges to improving the performance of their buildings. This report covers the role certain types of energy service agreements, combined with federal incentives, can play in scaling affordable multifamily retrofits.

This document is meant to guide Community Development Financial Institutions (CDFIs), green banks, and other lenders through measurement, verification, tracking, and reporting for clean energy loans for multifamily and commercial properties. It was developed for the HPN CDFI Readiness Cohort, which helped eight Community Development Financial Institutions create strategies to launch and expand clean energy business lending programs by integrating clean energy financing into their existing services.

This document focuses on capitalization sources with funding approaches categorized into "Direct" and "Indirect" capitalization strategies that Community Development Financial Institutions (CDFIs) can access for clean energy lending. It was created as part of the Housing Partnership Network (HPN) CDFI Readiness Cohort, where several leading consultants helped eight CDFIs with launching clean energy-focused lending products.

This report shares opportunities and challenges for financing and executing building decarbonization retrofits for unsubsidized multifamily housing in the Bay Area that have been recently acquired and rehabilitated by nonprofit affordable housing developers or could be acquired and rehabilitated in the near future.

This guide provides design and installation details for a standardized retrofit package serving California’s most common multifamily buildings. Technologies in this retrofit package were selected based on learnings from pilot demonstrations funded by California Energy Commission awards. The guide also includes financing recommendations driven by incentive opportunities for affordable multifamily housing through the federal Inflation Reduction Act and third-party lenders offering energy efficiency financing options for multifamily building owners.

New York State and New York City have enacted climate legislation with ambitious energy efficiency and greenhouse gas reduction targets. New York State’s Climate Leadership and Community Protection Act (CLCPA) and New York City’s Local Law 97 (LL97) impact various housing sector stakeholders, including owners, developers, renters, and financiers. Compliance will require significant investments over the next two decades, especially for high-emission buildings. While market-rate properties can finance upgrades through operating income or debt, affordable housing faces financial challenges.

Recommendations in this paper focus on strategies to make compliance more feasible and accelerate decarbonization for all housing sectors.