Where will your water heater be installed? In a basement, with no access to outside air?

I don't have one installed but needed a new water heater a few years ago and considered getting a heat pump model. I decided against it, and in favor of an electric Rheem Marathon, for a couple of reasons:

1. Heat pump water heaters are more mechanically complex than traditional electric, with more opportunities for failure. This was the main reason.

2. A heat pump water heater extracts energy from the ambient air and uses it to heat your water. If you're in a Philly rowhouse and your water heater is in the basement, the heat pump is going to be less efficient than it could be because it's extracting energy from your basement air, which is:

• Heated by your home heating system, which will have to work harder to make up for the lost heat.

• Limited in energy capacity because there isn't much air volume in your basement and it doesn't move around much.

So it's not as efficient as, for example, a mini-split heat pump you'd use to heat your house, where part of the system is outside the house and it can pull energy from the outside air, which is a "free" source of energy and also there's way more of it available.