Housing is one of the significant contributors to carbon emissions in the UK, estimated to account for approximately 15% of the country’s total carbon emissions. This research evaluates the lifecycle carbon emissions of various modern methods of construction (MMC), particularly category 2 premanufacturing structural panels, compared to conventional brick houses for affordable housing in the UK. The study employs the EDGE application modelling software to estimate the lifecycle carbon emissions of different construction methods and overall housing systems. The comparison of carbon emissions from the four systems reveals that modifying construction methods and materials from conventional to MMCs and local-natural materials can result in significant reductions of up to 75% during the construction phase and up to 15% during the operational phase, contributing to an overall decrease of up to 35% in the total lifecycle carbon emissions of the houses. Moreover, the research highlights that changes in construction methods have a more substantial impact on carbon emissions during the construction phase than during the operational phase. Material and construction method selection in affordable housing is identified as a critical factor significantly influencing the lifecycle carbon emissions. In conclusion, the findings emphasise the importance of adopting sustainable building materials and construction methods in affordable housing to reduce the lifecycle carbon emissions produced by the construction industry. Such measures not only contribute to lowering environmental impact but also enhance the overall sustainability of houses and households.