I would suggest to debug the gas and electric installations. That means monitor if there is any abnormal consumptions or leaks. Changing light bulbs types is l

I would suggest to debug the gas and electric installations. That means monitor if there is any abnormal consumptions or leaks. Changing light bulbs types is like a blind hit. My brother installed solar panels and could thus monitor consumption. He noticed abnormal consumptions and with his kids search the origin. They found a useless heater left on in some basement room. Problem solved. The nice thing is that it turned out as a game for the small kids and at the the same time they became more careful about devices consuming electricity for nothing.