The house was winterized back in Nov 2013, so the water was turned off and the water meter was removed to ensure the pipes wouldn't freeze (here in Michigan).

We're lucky if it gets a few degrees below freezing around here.

I've always cut the heat off too but with an upcoming vacancy and the 8 degree weather we're having, I've considered keeping the thermostat set to a temp just to make sure the pipes don't freeze.

I do not know where the duplex is located but Heat Pumps do not work well when outside temperatures are in the 30's or lower and with most of the country under an artic freeze I would not jump to conclusions based on his statement.

It seems to freeze or have issues especially over the weekend.

We put anti-freeze (safe type) in water tanks, traps and toilet bowls to reduce the problem even further.

I'm rather new to REI and I'm seriously worried about pipes freezing.

A pipe didnt freeze , a 1/2 inch sweat joint came apart , I just spent the last 4 hours with a rug doctor sucking water out of the carpet , and now have 4 large blowers going .

I told on Monday that I would repair the pipes until she let me know that she was going to be staying in the house again because if I fixed the pipes and she did not have heat then it would freeze and bust again at night.

I think you'd be hard-pressed to argue that the tenants are responsible for standing out in the cold during an historic freeze.