I have come to the conclusion that for me, this method will only work for iced coffee unfortunately, unless (possibly) I remember to leave the concentrate out on the counter the night before I want hot coffee, but really that is more planning then I want to go through for a cup of joe.
I mix the concentrate 50/50 with water so simply pouring hot water into that, even in a prewarmed cup would not do it for me. This morning I tried nuking the concentrate while my water boiled. I put it on for a minute. The mug got very very hot, but I let it cool while the water boiled so by the time the water was ready the mug, while still very hot, was not hot enough to burn me. Once I added the water the coffee was hot, but not as hot as I would have liked. The coffee tasted horribly burnt though. It was not a good cup of coffee. I have drank from this batch of concentrate previously so I know the concentrate is good. As iced coffee it is amazingly good. I guess I will just use this for iced coffee only.