So you’re always pumping hot water through your pipes? Does that not end up wasting quite a bit of energy? I guess in winter it’s not a big problem since you’re heating your house anyway, but presumably in summer it is just adding unwanted heat?

In the winter, as you note, it's not much of a waste, and it helps keep the pipes from freezing.

In the summer... this is central Texas, so the sun helps keep the water in the pipes hot, so I imagine that the pump is on less often than in the winter. I've not checked though. My gas bills are not out of the ordinary, so I think it's not a ridiculous waste.