What is the best insulation to use in a solar oven?

The best insulation for a solar oven is typically a material with high thermal resistance, such as fiberglass or foam board insulation. These materials effectively reduce heat loss, allowing the oven to maintain high internal temperatures. Additionally, using reflective materials like aluminum foil can enhance the heat retention by redirecting sunlight into the cooking chamber. Overall, a combination of good insulation and reflective surfaces will optimize the oven's efficiency.