Clean the glass of your stove with a 4:1 mix of wood/turf ash and bicarb of soda, with enough flash liquid to turn it to slurry.
Keep a large plastic jug by your sinks and basins. When running off water from the hot tap, fill the jug until the hot comes through. Then use the jug when you want cold water instead of turning on the cold tap. I watch my water meter and it does make a difference.