The Tenth Edition of the Directory includes energy performance ratings for over 100,000 products from 290 manufacturers, and the list of participants grows every month. NFRC, the country's only independent source of window, door, and skylight energy performance information, is strictly voluntary.
Most manufacturers understand that energy performance is important to their customers.
A national survey conducted by NFRC confirmed that consumers consider energy performance to be the single most important factor in deciding which windows to buy. The survey also found that 84 percent of consumers would prefer to buy a product whose energy performance is certified by an independent rating agency over one that is not certified. The NFRC system lies at the heart of many fenestration energy efficiency initiatives. In the 22 states that have adopted these codes, manufacturers must certify their products with NFRC or rely on a punitive default table when determining whether or not their products meet code requirements. Any manufacturer that wants to sell products in those areas must certify their products.