The hot water from our tank at the back of the house is producing hot water to the kitchen and laundry, but it is only luke warm (if we're lucky) in the bathroom (middle of the house) and ensuite (front of the house).

The house is 18 years old and single story, has PVC water pipes through the roof, and has a new Rheem hot water service installed 2 of 3 years ago.

Why would the temp of the hot water in some parts of the house be steaming hot, and not in the bathrooms ?
Thanks