Assessing Net-Zero retrofit feasibility for CityCare Housing Association

Thesis Abstract

Urban housing associations face mounting pressure to achieve net-zero energy performance amid rising retrofit costs, aging building stock, and evolving regulatory standards. This study addresses the feasibility of net-zero retrofit for CityCare Housing Association, a mid-sizedSocial Housing provider managing 3,200 dwellings across a mixed-use portfolio in a temperate climate. The aim is to evaluate technical, financial, and operational viability of a retrofit program that achieves net-zero carbon emissions by 2035 while maintaining tenant comfort and affordability. Specific objectives are (1) to inventory current building stock, energy use, and carbon footprints; (2) to identify technically viable retrofit packages aligned with net-zero targets; (3) to model lifecycle costs, energy savings, and payback periods under different funding scenarios; (4) to assess tenant acceptance and operability implications; and (5) to develop a decision-support framework to prioritise retrofit actions. The study adopts a mixed-methods approach underpinned by the Technological, Economic, and Social Triage (TEST) framework and guided by the Theory of Planned Behavior and Diffusion of Innovations to capture technical feasibility, financial viability, and stakeholder acceptance. A quantitative phase uses a comprehensive survey of 1,200 tenants to gauge comfort, willingness to participate in temporary relocation, and acceptable rent adjustments, complemented by an asset-level database of 3,200 dwellings, including age, fabric, insulation levels, glazing, heating systems, and controls. Energy performance is simulated using EnergyPlus for representative building archetypes (low-rise social flats, mid-rise-family blocks, and townhouses), calibrated with monthly utility data from the past five years. The financial analysis employs net present value (NPV), internal rate of return (IRR), and levelised cost of energy (LCOE) calculations across three retrofit pathways (a) energy efficiency upgrades only, (b) partial decarbonisation combining heat pumps with envelope improvements, and (c) full net-zero retrofit incorporating on-site generation and storage. Sensitivity analyses explore energy price trajectories, discount rates, and grant/loan scenarios from government and social housing funds. A qualitative component comprises 40 semi-structured interviews with executives, facilities managers, contractors, and tenants to understand governance, implementation barriers, and acceptance drivers, analyzed through thematic analysis aligned with the Theoretical Domains Framework. Expected findings indicate that envelope-first packages with selective heat pump integration achieve net-zero carbon within a 25–28-year horizon under moderate discount rates (5–7%), with NPV ranges from £12–20 million depending on grant uptake. The payback period is projected at 12–18 years for high-uptake scenarios, though affordability constraints and transitional cooling through energy tariffs remain critical determinants. Tenant acceptance is positively correlated with transparent communication, compensation for temporary displacement, and visible comfort improvements in common areas. The study anticipates identifying priority pilots by building archetype and location, along with a decision-support model that integrates technical feasibility, cost-effectiveness, and social acceptability to rank retrofit actions. The contribution to knowledge includes a novel, applied framework for net-zero retrofit decision-making in small to mid-sized housing associations, combining empirical performance data with stakeholder-oriented considerations and a multifunctional financial model. The research extends existing literature on housing retrofit by offering context-specific insights into financing mechanisms, governance structures, and community engagement strategies that enable scalable, equitable decarbonisation of social housing stock. The main conclusion posits that net-zero retrofit is technically feasible for CityCare with staged investments, robust tenant engagement, and targeted funding; the recommendations emphasize early pilot testing, modular retrofit packages, enhanced monitoring, and policy advocacy to unlock grants and concessional finance, thereby advancing practical pathways for net-zero transitions in similar housing providers.