The best choice for a typical Australian household is usually a mix of different controllers.Knowing Co2 level might be important in a child room, but unnecessary in the living room.The air + room sensor is ideal for rooms with a lot of traffic in and out, but not ideal in bedrooms.Purchase "Air" family products if you are a HomeKit user or plan to be.A good example for an Aussie home with 5 rooms would be:Sky's for the bedrooms (Air if you're going down Home Kit path).Airpro in living room/Air + room sensor for 2nd living area.