This week, three Building Products stocks are improving their overall ratings on Portfolio Grader. Each of these stocks is rated an “A” (“strong buy”) or “B” overall (“buy”).

This week, AAON (NASDAQ:AAON) is showing significant improvement as the company’s rating hops from a C (“hold”) to a B (“buy”). AAON manufactures and sells air-conditioning and heating equipment. In Portfolio Grader’s specific subcategory of Earnings Momentum, AAON also gets an A. Shares of AAON have increased 18% over the past month, better than the 3.5% increase the Nasdaq has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of AAON stock.

This is a strong week for NCI Building Systems (NYSE:NCS). The company’s rating climbs to B from the previous week’s C. NCI Building Systems designs, manufactures, and markets metal engineered building systems and products for the building industry. For more information, get Portfolio Grader’s complete analysis of NCS stock.

This week, PGT Inc. (NASDAQ:PGTI) is making solid headway. The company’s rating improves to an A (“strong buy”) from last week’s B (“buy”) rating. PGT manufactures and supplies residential impact-resistant windows and doors. For more information, get Portfolio Grader’s complete analysis of PGTI stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.