A solar energy collector is disclosed. The collector has a frame, a window and an absorber enclosed by the frame and a combined heat trapping and heat shielding arrangement between the window and the absorber. The trapping and shielding arrangement consists of a series of vanes extending from side to side of the frame and, in a heat trapping position, from the window to the absorber. In a heat shielding position, the vanes overlap when projected upon the plane of the absorber so that incident radiation must pass through plural vanes before reaching the absorber.