Portella Thermal Steel Series products are suitable for the most demanding climatic environments and carry National Fenestration Rating Council (NRFC) ratings with u-factors as low as .19. Thermal Steel Series products are Title 24 Compliant in the state of California. Title 24 is the most stringent energy regulations in the country. NFRC Rating Values for all Portella products are available upon request.
NFRC (national fenestration rating council) has taken on the responsibility of regulating the testing and certification methods for windows and doors. To achieve certification each product is computer modeled and then physically tested to verify the model. The result is a certified core product rating that can be altered depending on the glass type that is used. These results are available on the NFRC website for each company that participates in the program.