The DIRECTIVE 2002/91/EC of the European Parliament and of the council of 16 December 2002 about “energy performance of buildings” is the beginning of a revolution in energy certification normative. All European members are working to change their local normative. In Italy the directive has been transposed in a decree legislative D. Lgs 192/2005 characterized by max energy consumption value in relation of kWh/m² year and local Day Degrees. The energy dispersion calculation model has not been determined yet. The calculation model should joint thermo-physic building parameters with local climate trends. In some Italian local normative energy dispersion is reported to kWh/m² year measurement. Two examples are: Casaclima method (Bolzano Province) and the Milan Province method. These calculation models use Day Degrees to value weather variations. Several local Administrations have been working around this concept. In this paper we confront energy building consumption, with different north-south orientation. They are calculated according to Italian law (L.10/91- Standardized Energetic Requirements) translated in kWh/m² year, with Casaclima and Milan Province method.