Large windows are becoming popular. It is only natural because larger windows let more light into the interior. External blinds can protect these large windows (up to 22m2 for vertical blinds and up to 30m2 for horizontal blinds) from the sunlight without any sort of middle guides. The external sun protection keeps the sunlight out, even before it hits the window so that the temperature inside remains under control. Therefore, in warmer seasons, the inside stays up to 7°C cooler, without the need for an air conditioner.