MacBook Air Haswell Battery Life with Mavericks???

I can't find a single article/video of someone who has mavericks beta on a 2013 macbook air and tested the battery life. One of mavericks key features is drastically increasing battery life buy only supplying power to the tasks your only using at that moment. With mountain lion the 2013 macbook air get 12 hours of battery life, so how much will this improve with mavericks, 14 hours? 16 hours? 18 hours? Well no one knows because no one bothered to test yet. If anyone knows anything about this please post!