Hi. Here in California we need to conserve water. Every time we need hot, we pour all the cold water in the hot pipe down the drain until the hot arrives. Could we use a thermostatic mixing valve at the point of use, fed by a small point-of-use hot water tank on the hot side (140F/60C) and by central hot water on the cold side (70F/25C rising to 110F/43C when the hot arrives)? The heater can run on normal 120V and sized to match the volume of water in the pipe. Thanks!