So you get up just after the heating comes on - can't be very warm then - and leave the house just when it's reached the desired temperature.
Then it comes on an hour before you arrive home - that means it should be warmer - but goes off half an hour after you arrive home. Why?
Then it comes on at 8:00pm, presumably because you are feeling the cold. and goes off at 9.30pm; I assume you go to bed early because you have to get up early.
It just doesn't make sense.
It's not a case of leaving the heating on all day, but being sensible with your times. Which programmer and room thermostat do you have?
PS If you garage is unheated the house has four outside walls.