Asiye Aslan, PhD



In light of the current energy problems, building envelopes must achieve thermal insulation in buildings by consuming the least amount of energy, thereby minimising energy consumption.

This study determined the optimum insulation thickness of external walls, ceilings and floors of buildings as well as energy saving and payback periods in 81 city centres in Turkey. The calculations were performed for commonly used walls, ceilings and floor constructions.

The life-cycle cost analysis and Turkish standard TS 825 (‘Thermal insulation requirements for buildings’) were also considered. In the calculations, the decreasing factor applied in TS 825 for surfaces that have no contact with outer air was considered.

The results showed that the optimum insulation thickness of the external walls, ceilings and floors ranged between 3.5 and 20.0, 4.6 and 19.7 and 0.7 and 14 cm, respectively, depending on the type of energy and insulation material used.

These findings suggest the possibility of saving up to 75% energy on the external walls, 90% on the ceilings and 85% on the floors. Additionally, a saving of 12–13% is likely obtainable in Turkey’s total energy consumption when the optimum insulation thickness is applied to all residential buildings in the country.



energy energy conservation thermal effects