This study investigates the feasibility of energy conservation and economic viability through the implementation of two distinct energy conservation measures (ECMs) aimed at reducing transmission loads via thermal mass. The first ECM involves the utilization of commercially available Gypsum-based cow dung (Vedic) plaster for fly ash brick (FAB) cavity walls, while the second ECM entails applying cool paint to the roof. Experimental analyses were conducted to assess temperature variations and heat flux within an experimental facility located at MNNIT Allahabad campus (25°27'N and 81°51'E). The experiments measured heat flux, indoor and outdoor temperatures for both base and proposed building envelope cases. The calculated U-values from experiments were 2.58 W/m^²K for a standard fire clay brick wall, 0.6370 W/m^²K for Vedic plastered FAB cavity wall, 2.891 W/m^²K for a standard roof, and 2.8 W/m^²K for a roof with cool paint. Replacing conventional brick with Vedic plaster FAB cavity wall and cool roof on the conventional roof results in a 56% reduction in the total thermal load of the base case building. The implementation of these energy conservation measures results in a monthly electrical energy saving of approximately 18.6 kWh/m² per unit envelope area, with a corresponding reduction in GHG emissions of up to 20.4 kg CO2eq/m² per unit envelope area. These calculations assume a 20-hour operation of HVAC systems with a coefficient of performance (COP) of 4. The uncertainties associated with the measurements were also calculated to assess the feasibility of the experiments. The uncertainty associated with heat flux, inside and outside temperature measurements are ±7.5%, ±3.2% and ±2.5% respectively.