All the big Japanese makes have them. They basically look like a water tank with the outside portion of a mini split air conditioner hooked up next to them.

With my power company in Japan, by going "all-electric" (having an eco-cute and induction stove), I qualify for a rate plan where I can trade off solar power peak hours (half price) for the duck curve hours (double price), so I have my water heating only running during cheap hours and cut down on air conditioning during the expensive hours.

Ours is from Mitsubishi and is just the builder-grade one from our fix-rate renovation company. It will connect to the wifi so you can start a bath from an app on your phone on your way home from work. There's also an intercom between the bath and the kitchen so mom can tell the kids to get out of the bath, dinner is done. Traditional Japanese values.

Mitsubishi https://www.mitsubishielectric.co.jp/home/ecocute/

Panasonic https://sumai.panasonic.jp/hp/

Daikin https://www.ac.daikin.co.jp/sumai/alldenka/ecocute/structure

Corona https://www.corona.co.jp/eco/

Noritz https://www.noritz.co.jp/product/kyutou_bath/ecocute/