Show them how the house runs and bring them into conversations about it. Show them how and where to recycle, or even compost. Explain why it’s a good idea to conserve energy by turning off the lights when you leave a room, or to conserve water by turning off taps when brushing teeth, or taking short showers or shallow baths. Try to avoid single use items, sending them off to school with reusable water bottles and paper bags or lunch boxes rather than packaged or cling film-wrapped food.
Discuss why a second hand piece of furniture, or a toy or a jumper might be better than a new one, or why you’re using an eco-friendly cleaning product, or hanging clothes out to dry rather than tumble drying. As they grow, bring them into major purchasing decisions for the house, like whether or not you really need a car, or a dishwasher, and, if so, whether you can find one that is less harmful to the environment.