Paul
I have a TCH and my office is also around 2.5 miles away from my home. I live in GreenBay, Wisconsin and recently the temperature drops to around 30F. I drive through the neighbourhood with couple stop signs and the speed always stay within 25 - 35mph.
Just give you an idea how the TCH performs in my situation. I do not have the Nav, which shows me exactly how my MPG per trip, but there is a trip computer that tells you an approx MPG per trip below the speedometer. My MPG is around 27 - 30 for that approx 2.5 mile trip. Couple month ago when the temperature were still above 60, I can easily reach the MPG above 30 or even 40. I always have my air con on. I am an easy foot driver that I don't accelerate hard. I am expecting the MPG to continue to drop because of a more colder weather a head of Wisconsin.
Hope my info helps your decision on whether to get a TCH or retain the HAH.
Ian