It takes a few minutes for my tankless water heater to warm up, so we end up wasting a lot of water in our shower. Is there a way to avoid this? A friend mentioned a “comfort valve” or something? What is it and how does it work? Or is there another solution? Thx!
If you're worried about the water being waste recirculation pumps would do. Set them to run based off motion in your bathroom and kitchen.