My daughter has one, but her kitchen, bath and laundry room are quite a ways away from each other. So she doesn't really like it. It would be better if the heater is really close to the use.
We have geothermal. With that you get free hot water whenever the heater or the air conditioning is running. (Air conditioning comes with it as a freebie. So is the hot water.) So over the summer, we need very little air conditioning, but for the other three seasons, the geothermal unit acts as a pre-heater. We love it. Last summer our electric bill for the month of August showed that we spent $1.27 for running the geothermal, and that just might have been for heat. LOL