Why we DON’T shave double coated dogs! 
Shaving a double coat can have some irreversible consequences. The coat is made up of a downy undercoat and a more coarse guard coat. When shaved the undercoat grows faster than the top coat creating a very unappealing look. The guard coat or topcoat can also change texture once shaved. There is only a 50% chance your dogs double coat will recover over a significant amount of time.
Myth: shaving my double coated dog will help them be cooler in warmer weather. FALSE! Shaving them in fact destroys the natural airflow circulation created by the space in between the undercoat and the guard coat.
Shaving your double coated dog comes with other issues too, such as the coat being more likely to Matt as it grows, sunburn, destroying the coats natural ability to regulate your dogs temperature and the coat never being the same again. (Texture, length, ect.)
Alternative: instead of making the ill informed decision to shave your double coated dog get a de shedding treatment. This will get a lot of that Downey undercoat off the dog. Cooling them and flattening the coat. A tight trim along with deshedding will lighten the coat and help you manage the amount of fur while keeping the coat healthy.
By Michelle McCauley - The Mindful Groom @mybestfriendsmunchies