Commercial buildings in Malaysia contribute to 35% of the total electricity demand. During the recent COVID-19 pandemic, the global economy faced a challenging situation that forced many businesses to shut down. However, fast-food restaurants with drive-through features managed to get through this pandemic phase without much effect from the economic impact. Since COVID-19, the operational guidelines have changed for restaurants. However, from an energy perspective, fast–food restaurants are high energy consumers in the retail sector. This paper analyses the load profile of fast-food restaurants and the potential strategies that can be adopted in a free-standing fast-food restaurant. From analysis, it is calculated that a total of RM 97,365.9 of utility savings can be obtained in a year. A total of 91,392.1 kg CO₂, 881.8 kg SO₂ and 385.5 kg CO pollutant emissions can be reduced. The BEI for the restaurant was reduced to 856.4 kWh/m²/year. By converting to energy-saving strategies, the return on investment was 27.3% and 3.7 years, which is a very short period of time and is attractive for businesses of this nature.

This research aimed to investigate the impact of passive design techniques on building envelope design. Whereas assessment of the heat transfer rate through building envelopes is frequently done using the OTTV standards worldwide. The research includes two parameters for measuring the thermal performance of the building facade. The first measurement uses a methodical approach to calculate the wall's thermal transmittance (U-values) and then moves on to calculate the OTTV. The OTTV of the case study was computed using the OTTV formula given by the Malaysian Standard. At the same time, building specifications were determined via a site examination. After that, the OTTV was compared with a recommended standard value for the local climate. New building materials and specifications are proposed when the OTTV value exceeds the standard range. The results indicated that the present OTTV value is 55.31 W/sq.m, more significant than the proposed value for a standard commercial building. It recommended considering 6 mm single glazing low e-glass for all windows on the East, West, South, and North elevations. As a result, the OTTV was lowered to 45.34 W/sq.m. Since air conditioning consumes most of the energy in an office building, lowering the OTTV will result in a slightly reduced airconditioning cooling load.