It is good to use red tiles on the roof in geomantic omen, because from a physical point of view, the wavelength of red is the longest. Aircraft in the air can be clearly identified to avoid unnecessary accidents. This is one of them. Secondly, from an artistic point of view, red is warm and blue is cool. Red roofs give people a warm feeling, especially in northern cities. Thirdly, red is an auspicious color in China, which always gives people a feeling of closeness. So the roof tiles of most villas are red.