As for now “Sale” countdown is only available for our Visual Composer element “Products grid”. To activate it there you need to set your “Sale” date schedule for the product and check this option while adding “Products grid” element to your page. If you want to show this countdown also on your shop page or single product page so we will introduce this ability in our next theme release (probably in 7-10 days).
Thanks for the quick answer! Would be nice to implement that as a regular theme function. However, I figured out how to add it to the product page already by using the visual composer code and just adding it to the product description. However, an theme implemented solution for that would be awesome!