Are therma tru doors good? This question evaluates the quality and performance of Therma-Tru entry doors. Therma-Tru is a well-known manufacturer of fiberglass and steel entry doors for residential and commercial properties. Therma-Tru doors are highly regarded for their durability, energy efficiency, and security features. They are constructed using a combination of fiberglass and steel, making them resistant to warping, denting, and rotting. The doors also feature polyurethane foam insulation, which helps to reduce heat transfer and lower energy costs. Furthermore, Therma-Tru doors are equipped with heavy-duty locks and reinforced frames for enhanced security.