Building fabric retrofitting is an important first step in improving building energy efficiency. The United Kingdom’s (UK) housing stock is one of the most inefficient in Europe, and Northern Ireland has the second-highest level of fuel poverty in the UK. This Northern Irish case study developed three fabric retrofit scenarios that estimate potential demand reductions, CO2 emissions removals and retrofit costs. The first scenario reduces domestic demand by 10% and removes 6% of domestic emissions. The second scenario is more ambitious than the first, and results in an 18% reduction in demand and 12% of emissions removed. The third scenario proposes fabric retrofitting to PassivHaus standard and results in a 42% reduction in demand and 27% of emissions removed. Furthermore, retrofit schemes can provide up to approximately 350,000 jobs annually between 2022 and 2050 for the Northern Irish population. This study demonstrates how fabric retrofit scenarios can be streamlined to the unique features of a housing stock. It shows that fabric retrofit research is important for the formulation of energy efficiency policy and emphasises that domestic sector retrofitting will yield socioeconomic and environmental benefits locally and internationally.