I needed a pair of thermal curtains for a bedroom in my house that has a very large window and gets very cold in the winter and very hot in summer, regardless of the temperature throughout the rest of the house. I put these up, and they've done a great job of keeping the cold out so that the room feels more comparable in temperature to that of the rest of the house. I have yet to see how they work with the heat, but thus far, they have served their purpose. Also, these were the best thermal curtains I could find in terms of price that were large enough to fit the window in question. At first, there was concern of how the black curtains would look in the room, but because they are made of a microfiber material, it is kind of a soft black, giving the curtains a bit of a warmer, more inviting appearance than was originally expected.