Home Energy Upgrades as a Pathway to Home Decarbonization in the US: A Literature Review

This work aims to characterize how home energy upgrade projects and programs in the US
have evolved over the past decade. It also identifies what changes are needed to drive expansion
of the US energy retrofit market in such a way that addresses carbon emissions from buildings,
improves resilience and upgrades the housing stock. This review focuses on whole-home energy
upgrades, targeting deep energy retrofit savings of >30%. The topics we cover include trends in home
electrification, US and European home energy upgrade programs, energy upgrade measure costs,
business economics, and health effects. Key changes in project design noted in this review include:
(1) the electrification of dwellings with rapidly improving heat pump systems and low-cost solar
photovoltaic technology; and (2) a shift away from high-cost building envelope strategies and towards
more traditional home performance/weatherization envelope upgrades. Promising program design
strategies covered include: (1) end-use electrification programs; (2) novel financing approaches; (3) the
use of carbon-based program and project metrics; and (4) “one-stop shop” programs. Based on the
existing market barriers, we suggest that the industry should adopt new project performance metrics.
Additionally, market drivers are needed to spur widespread energy upgrades in the US housing
stock. Costs must be reduced, and projects designed to appeal to homeowners and contractors.