A new roof can indeed help keep a house cool. The choice of roofing materials plays a crucial role in determining how well a roof can resist heat gain from the sun. Certain types of roofing materials, such as metal roofs or specialized reflective shingles, have high solar reflectance and thermal emittance properties, meaning they reflect more sunlight and release heat more efficiently than standard materials. By reducing the amount of heat absorbed by the roof, these energy-efficient roofing materials can significantly contribute to keeping the interior of a house cooler during hot weather.