What is a low-energy house?

A low-energy prefabricated house is an energy-efficient house. In Croatia, a low-energy house is defined as a house that consumes less than 40 kWh/m² of heating energy per year. Such energy consumption can be expressed more clearly as the equivalent of 2.7 litres of heating oil per m², which is why a low-energy house is also called a three-litre house.