Hi JLo,
8 degrees is just above the temperature where the aux' heater steps in to provide additional heat to warm the engine. Even so, as long as your journey is sufficiently long (time and distance) and fast, you should be getting some heat. Rather than turn the climate control off, I would drop the temperature down to 19 degrees and see what happens. I would suggest that your car possibly has a stuck engine thermostat.
John