To limit the probability that different values for the proposed and reference houses with regard to floor area, heated volume and number and types of rooms will be used as input in the energy model calculations, which could lead to inaccuracy of the model, which could lead to overestimation of the energy used by the reference building or underestimation of the energy used by the proposed building, which could lead to excessive use of energy, which could lead to an unacceptable effect on the environment.