Rapid urbanisation leads to the growing of cities both horizontal and vertical dimensions, what in turns leads to the increased energy consumption and poorer environment quality. Thati is why European Initiative on Smart Cities takes place. The aim is to improve quality of life and local economies through the investments in sustainable energy and reduction of carbon emissions. Residential buildings in Latvia are one of the essential heat consumers during the heating season. The majority of Latvian as well as European residential buildings were constructed within the period from 1965 to 1990. The average heat transfer coeficient of typical homogeneous single layer external wall of Latvian multi apartment building as well as all buildings constructed in USSR is 0.80 till 1.20W/(m2K) (Borodinecs et al, 2013; Latvia State Agency, 2006). This paper presents study on multi apartment buildings renovation specifics in Latvia and its infuence in total energy consumption and possibilities to spread different energy-efficient solutions from single house to the city scale.