Are you building a house? Are you at the stage of choosing a heating system? Remember that for you, as the user, the indicator of useful energy is most important. It means the actual electricity consumption you pay for.
You will probably be enticed with the “initial energy standard” index. It results from politics and not from technology. So it will tell you nothing about the energy class of the building.
I recommend the article by Mr. Jurkiewicz. Although written for specialists, but the examples are worth reading. For instance the one comparing two buildings, the first of which actually consumes 10 times less energy than the other. In zloty, electricity supplied to the building with good energy characteristics will cost PLN 1800 annually, the other supplied with pellets will cost PLN 5000.
One building with very good parameters of walls and windows (heat transfer coefficient for walls below 0.15W/m2K), with heat recovery from ventilation, with heat demand (without warm water and auxiliary energy) of, for example, 20 kWh/m2. The annual heat consumption will be therefore 3,000 kWh/year (final energy).
The second building, with much worse wall parameters (heat transfer coefficient well above 1.0 W/m2K), and poor windows, where the heat demand is 200 kWh/m2 per year. Therefore, the annual heat consumption will be 30,000 kWh (final energy).
The first building is heated by electricity (underfloor heating), so
P1 = (3*3,000kWh/year)/150m2 = 60kWh/m2year
EP2 = (0.2*30,000kWh/year)/150m2 = 40kWh/m2yearSource: