The versatility of Frank by Ostaco Enersense windows allows for a huge number of combinations of windows to be built. Mix and match different sizes with fixed and operating windows, along with black paint on the interior and exterior to put your own custom look in your home. The modern look of the Enersense window gives the best option for a contemporary or modern home. Add a smooth fiberglass door from Thermatru with direct set sidelite to maximize glass and you have the perfect modern home.