A roof truss having a triangular cross section comprising a first side, a second side, and a base, wherein the roof truss comprises: a solar energy collector occupying the first side of the roof truss, the solar energy collector comprising: a transparent layer, a light-absorbing layer, and an inner layer; wherein the transparent layer and the light-absorbing layer define a first channel between them, and the light-absorbing layer and the inner layer define a second channel between them; a connection path located near the base of the roof truss connecting the first channel and the second channel; a first port located in the first channel near the apex of the roof truss; a truss air duct connected to the first port for receiving air that has been heated during its passage through the first channel; and a first air gap located in the second channel near the apex of the roof truss for receiving air from a light collector; characterised by: a light collector occupying the second side of the roof truss, the light collector comprising: an outer glazing and inner glazing, wherein the outer glazing and inner define a third channel between them and wherein the third channel is connected to the first air gap; and an air intake vent located near the base of the roof truss in the inner glazing for receiving air from inside a structure. a solar energy collector occupying the first side of the roof truss, the solar energy collector comprising: a transparent layer, a light-absorbing layer, and an inner layer; wherein the transparent layer and the light-absorbing layer define a first channel between them, and the light-absorbing layer and the inner layer define a second channel between them; a connection path located near the base of the roof truss connecting the first channel and the second channel; a first port located in the first channel near the apex of the roof truss; a truss air duct connected to the first port for receiving air that has been heated during its passage through the first channel; and a first air gap located in the second channel near the apex of the roof truss for receiving air from a light collector; a transparent layer, a light-absorbing layer, and an inner layer; wherein the transparent layer and the light-absorbing layer define a first channel between them, and the light-absorbing layer and the inner layer define a second channel between them; a connection path located near the base of the roof truss connecting the first channel and the second channel; a first port located in the first channel near the apex of the roof truss; a truss air duct connected to the first port for receiving air that has been heated during its passage through the first channel; and a first air gap located in the second channel near the apex of the roof truss for receiving air from a light collector; a light collector occupying the second side of the roof truss, the light collector comprising: an outer glazing and inner glazing, wherein the outer glazing and inner define a third channel between them and wherein the third channel is connected to the first air gap; and an air intake vent located near the base of the roof truss in the inner glazing for receiving air from inside a structure. an outer glazing and inner glazing, wherein the outer glazing and inner define a third channel between them and wherein the third channel is connected to the first air gap; and an air intake vent located near the base of the roof truss in the inner glazing for receiving air from inside a structure.