Reviews for Okna windows on WindowReplacementCost.co and ReplacementWindowsConnect.com are generally positive, but some reviewers report problems with the windows. Many reviewers say that Okna windows have good U-factor values and qualify them for tax credits, but some complain about high prices and unsafe locking mechanisms.
Okna windows come in different models, including the Starmark 900, EnviroStar 800, Insul-Tec 500 and Precision Weld 400. According to reviews from users, each of the models has unique positives and negatives. Going by expert advice from some of the reviewing contractors, the effectiveness of the windows mostly depends on the window installer and dealer.