Yes, but it's actually not that simple. If it blasts too hard there's the chance it will have to start cooling. I suspect cars use linear control for heating a

Yes, but it's actually not that simple. If it blasts too hard there's the chance it will have to start cooling. I suspect cars use linear control for heating and cooling, it's easy to implement and well understood. In that case it will not use max heat until it reaches the target and turning it to max could get you there faster. It's actually really not a simple problem, look into control theory of you're interested.