ELI5: Explain Like I'm 5

Heat recovery ventilation

Heat Recovery Ventilation is a way to keep your house warm and comfortable without wasting energy. It works by taking the hot air from inside your house and using it to heat up cold air from outside. That way, the warm air is not wasted and the cold air is heated up without using any extra energy. This can help you save money on your energy bills and keep your home comfortable.