M-F, no specific start time, but I generally start between 7-8, sometimes earlier when I want to get off early or need to get something done before a place opens up.
Typically I work 8-10 hours a day, but there have been plenty of 16+ hour days in the past too. I do the whole commercial HVAC thing, so sometimes you're not done until you're done. Typically I work 40-45 hours a week, rarely get close to 60, but mother nature seems to determine that more than I do.
I'm on call every 3-4 weeks, unless it's heating season, then I generally get all the boiler calls.
Not a bad gig overall, lots of freedom and flexibility for the most part. Sure beats being in an office most days!