Global warming is adversely affecting the UK’s climate, causing an increase in dwelling temperatures and more energy consumption to achieve better indoor conditions, resulting in more carbon emissions. In this research, thermally heavyweight construction benefits are identified and compared with the lightweight building fabric for not only current climatic constraints but also for future projections of London’s temperature till 2080 are simulated. Multiple iterations are performed in the thickness and placement of the thermal mass of walls, floors and roofs to achieve lower temperature profiles and energy consumption for ambient conditions inside dwellings. In all our findings, heavy-weight dwellings performed well under different scenarios to achieve set objectives. We recommended various dwelling construction details which produce low-carbon and can be used as per the availability and suitability of materials.