The two-storey house is located in Kastoria in the settlement of Poria. It was built in the early nineties. The increased operating costs of the building and especially the increased annual heating costs led the owners to the solution of a deep energy retrofit.

The interventions chosen for the energy retrofit were the significant enhancement of the envelope insulation (external wall insulation, new insulated roof), while at the same time the windows were replaced with new highly efficient ones.

The interventions in the electromechanical facilities of the house include installing an air-water heat pump system with the use of under-floor heating. Domestic hot water is available from a new solar collector.

After the completion of the energy retrofit, the energy consumption for heating, cooling and domestic hot water decreased by 65%, leading to significant energy and cost savings.