According to Vastu Shastra, windows in a house should ideally be in even numbers such as 2, 4, or 6, as these are believed to promote balance and positive energy. Odd numbers like 3 or 5 are considered inauspicious and may attract negative vibrations. Therefore, while planning or constructing a home, special care should be taken to maintain an even number of windows to ensure harmony, peace, and good Vastu within the living space.