The housing situation in South Africa needs serious improvement and intervention. There is a huge amount of housing backlog, and the living conditions, housing quality in low-income areas is beneath an acceptable level. The solution at present is considered to be large scale, low-cost housing projects, supported by governmental subsidies. Providing indoor comfort is a critical issue – the dwellers often don’t have proper means of heating during the cold winter period. Implementing solar energy might possibly be the solution to resolve this problem. This paper evaluates a design of a low-cost house that utilizes solar energy to provide indoor comfort. Evaluation is based on theoretical calculations, dynamic computer simulations, and on-site measurements and testing. The results show positive results. Theoretically the current design for a low-cost house working with solar technology functions sufficiently, even more so if the improvements recommended by this report will be implemented. It was found that factors having strong effect on system performance were: - the heat loss coefficient of the rockbed – installing heat insulation around the rockbed, thus reducing the heat loss coefficient from 11.35 kJ/hm2K to about 5 kJ/hm2K, the low values of indoor night temperatures can be increased from 14?C to about 18?C. - the flow rate of fluid circulating in the closed loop – by reducing the flowrate from 0.32 kg/s to 0.16 kg/s, the indoor temperatures during the night can be increased from 14?C to about 16.5?C. - by combining these improvements, a nighttime indoor temperature of about 22?C can be achieved. Further testing is required to confirm these presumptions, but until then this new, innovative design silution is deemed to be a successful trial in improving indoor comfort through utilizing solar technology.