Perfect Tempature Inside Auto

An information dash light that tells me how long it will take my auto to warm up to lets say 65 degree tempature inside of the auto. Or how long it needs to run to get cooled to say 60 degree tempature inside of the auto. For those of us in Kasas with tempature
changes and with children we want to run the auto awhile to get a safe tempature. But how long do we need to run it? 15min., 30 min? It's a guessing game. An information panel would be great!!!! Each time I get in and turn on the key my perfect tempature would be preset and the car computer would tell me how long to warm up the auto to get to my preset perfect in car tempature. This would save fuel and customer time each day.
Okay idea. I know sometimes in the winter my auto is sub zero after warming up for 10min. This idea could work.
art hansen 01/29/2012
Letting youre car idde while you wait for it to heat up or cool down does not save fuel. Second thing is in the sunner just rool down the windows to let all the hot air excape. If you live in the north where you get snow just get a block heater that will keep the engine warm so it will be easier to start and warm up faster.