FAQ What is the recommended distance for the CFF4 model from the wall? The recommended distance for the CFF4 model from the wall is 5 ft.Can other types of lamps be used with the CFF4 model? No, only fluorescent lamps are recommended for use with the CFF4 model.Is the CFF4 model suitable for use in large rooms? The CFF4 model can be used in rooms of varying sizes, but the optimal results are achieved when the recommended distance from the wall is maintained.