In Lithuania buildings (or parts of them) are classified into 9 classes according to their energy performance: A++, A+, A, B, C, D, E, F, G. Class A++ is considered to be the highest class and refers to a building that is almost energy-free. The energy performance class of a building shall be determined by the value of the energy efficiency index.
The energy performance class of new buildings must be not less than A++ if the construction works will start after 2021 1st of January. The energy performance class shall be not less than C for modernized buildings if the construction works started after 1st of January 2014.
Thermal requirements for partitions of energy efficiency class C buildings: roofs / ceilings U³0.16 W/m2K, partitions bordering the ground U³0.25 W / m2K, walls U³0.20 W/m2K, windows U³1.60 W/m2K, doors U³1.60 W/ m2K.
For class C buildings, the air tightness test is mandatory when the design and construction is financed from the budget of the Republic of Lithuania and (or) the European Union. The air change rate of energy performance class C building at a pressure difference of 50 Pa between the inside and outside of the building shall not exceed 2.00 1/h.
Author: Jurga Kumžienė (KTU)