Don't get me wrong, I have a bunch of rack pull servers and they're great for the price but I colo mine for less/server than the power bill/server would be at home and have them ona faster connection. I stick with low power options for light in-home usage
Modern processors do some clever tricks to minimize using power if it is not needed, and have gotten progressively better at it. For home use cases, it's often worthwile to spend more money to get newer or otherwise more efficient PC components. This is especially true in areas where electricity costs are higher (e.g. average price per KWh can be almost twice as high in the Benelux when compared to the US).
One thing to get an indication about how good a CPU/chipset is is idle power usage of a system. It seems Ryzen is even better at this than Intel's already excellent Sky/Kaby Lake architectures [1], possibly because of the fact that Ryzen motherboards contain fewer components. On the contrary, the Ivy Bridge architecture of the chip mentioned by the parent cannot be considered competitive from a power consumption perspective, despite still being a great performer.
[1]: https://www.pcper.com/reviews/Processors/AMD-Ryzen-7-1800X-R...