The thermal design of a nearly zero energy one-family house, in North-Centre Italy, is described. The house has a timber frame, a wood-fiber thermal insulation for the roof and a wood-fiber plus YTONG blocks thermal insulation for the lateral walls. Forced ventilation with high efficiency heat recovery is employed. Heating and cooling is provided by an air-to-water heat pump connected to floor radiant panels. Domestic Hot Water is supplied by a thermal solar collector and a heat pump for DHW. The electric energy for the heat pumps and for the forced ventilation system is supplied by PV collectors, which provide also most of the electric energy for lighting and appliances. The thermal design is based on dynamic simulations performed through the code TRNSYS 16.