Housing has an impact on occupants' health and well-being in addition to providing physical shelter. This study examined the effects of residential design characteristics on indoor environmental quality (IEQ) and occupant health in Nigeria. Significant outcomes were seen when environmental measurements and health questionnaires were combined in data collection from 236 houses. Findings show enhanced ventilation via window design and sustainable materials can alleviate respiratory and tiredness symptoms. The study concludes with a call for health-focused architectural interventions in house design and recommendations centre on design principles customised for tropical regions to foster healthy indoor environments.