A method of fabricating a condenser tube having a pre-determined tube length and multiple channels including the steps of forming an aperture in a flat strip of metal; moving the flat strip through a plurality of forming operations to fold into an enclosed tube containing channels, which channels include the aperture in their sides and bottoms; and severing the enclosed tube across the aperture to separate the enclosed tube into one condenser tube. The aperture eliminates the need for the channel sides to be severed, hence only the portion of the condenser tube enclosing the channels requires severing. Each pair of apertures is spaced from the next pair of apertures by the pre-determined tube length so that each sever produces one condensing tube of the pre-determined tube length with the apertures being divided into open notches. The invention also includes a heat exchanger utilizing the condenser tube with channel sides containing portions of the apertures.