The implementation of energy efficiency intervention in the residence of the university campus can lead to a reduction in the electricity consumption and electricity bill. The study focused on retrofitting a 12 kW, electric boiler with two storage tanks of 1000 L capacity with a 4.0 kW air source heat pump (ASHP) unit, to provide sanitary hot water at 55oC. A data acquisition system was built and deployed in monitoring the baseline performance of the electric boiler and the actual performance of the retrofitted ASHP water heater. The results depicted that for the electric boiler, the annual energy consumed was 48858.21 kWh, while the annual energy consumed by the ASHP water heater was 14052.27 kWh, respectively. In addition, the annual energy saving due to the retrofitting with an air source heat pump unit was 34805.94 kWh. The payback period of the ASHP unit was 1.7 years using the net present value of money with an Eskom tariff of R 1.50/kWh and an annual tariff hike of 15%, coupled with an annual rate of return of 6.5%. We could affirm that, by retrofitting the electric boiler with a heat pump in the student residence on the University of Fort Hare campus, there is a potential viability of the technology, since the payback period is well smaller than the life span (15 years) of the technology.