GE GeoSpring heat pump water heater. I have one of these, as do a number of our clients. No issues, despite the mediocre reviews on Amazon (note they are all 3+ years old.) Probably lots of DIY errors. This is my favorite hot water solution. If you have a larger household (4+ people) get the 80 gallon model. Sadly, this brand is being discontinued due to low sales, but other brands have similar models and pricing (State and Rheem.) There is a $300 federal tax credit as well for them, check GE’s website.