The moderate climates of the tropics had a characteristic day temperature range between 25-30˚C which is now reaching an average peak temperature around 36˚C. This drastic change in temperature profile has given rise to uncomfortable indoor condition in the living spaces. The extra energy that is required for cooling living areas has to be met by producing more electricity which is potentially unsustainable. There is a need to adopt a technique that reduces or eliminates the requirement of extra energy for the space cooling, but still, provide the required comfort inside the building. Providing a thermal insulation to the building is one such technique that could be adopted to achieve maximum energy efficiency. This thesis makes an attempt to explain the performance of passive techniques for reducing the energy consumption in buildings situated in moderate climates. Reflective coatings and building insulation are addressed in this work. This thesis reports experimental investigation on the thermal behaviour of building envelops in moderate climate. Two techniques normally employed for improving building thermal management, namely, reflective coating on roof and building insulation with different materials are explored. A part of a large building with the exposed roof, the south and the west walls has been chosen for the study. The building envelop was instrumented to record the inside wall temperature, air velocity, heat flux, indoor air temperature, humidity, and atmospheric pressure. The tests were conducted for over a month�s duration. Roof coating has resulted in a drop of 4˚C in the indoor air temperature. Several biomass based insulation materials were tested for conductivity results indicates reasonable performance. A typical U value drop of 80% to 85% in walls and 60% to 75% in roofs can be obtained by providing 150mm thick insulation material.