Air conditioning always switches on at start

Hi! I bought a SEAT Ibiza Freeze from the year 2000. Now it’s the case that the air conditioner (“AC” on “car” at the start. In the manual it says that this causes a high fuel consumption. I want the heating to be on only when I activate it to save fuel (which is relatively important as a student). I want to: Engine on -> Ventilation off. I drive 3-4 km, the engine is warm and then I want to turn on the ventilation first to warm my car. How can I get a car? when starting the air conditioning will always be annoying in the long run. Thank you for your answers