A very easy to build, inexpensive, CPVC liquid (hydronic) solar hot water collector that you can use to heat your home or for domestic hot water. This collector is significantly outperforming my pex collector in testing so far. Enjoy free heat, courtesy of the sun!
Get a programmable thermostat for your water heater = turn the temps down an hour or two after you go to bed, or during the warmer times of the day, or the times when you typically don’t use your hot water. No reason to heat what is not being used!