Wonder Windows is proud to carry the Okna line of Windows. For homeowners in the Northeast investing in top energy efficient windows is a way to stay warmer in the winter and cooler in the summer. Each year EnergyStar.gov designates manufacturers and specific Windows as that years Most Energy Efficient. For 2015 Okna was designated this rating for many of its Windows. There is the selection of Okna Windows designated as 2015 Most Energy Efficient.

OKNA Windows & Doors (Double Hung Windows)

Product Line CPD Number U-Factor SHGC Frame Type PG Climate Zones
Insul Tec – 500 / 5500 Series OKW-K-18 0.15–0.19 0.23–0.26 Vinyl 50 N, NC
Insul Tec – 505 / 3500 Series OKW-K-20 0.20 0.23–0.26 Vinyl 50 N, NC
Precision Weld – 400 Series OKW-K-22 0.20 0.26 Vinyl 50 N, NC
Enviro Star – 800 Series OKW-K-23 0.16–0.20 0.23–0.25 Vinyl 60 N, NC, SC, S
Starmark – 900 Series OKW-K-32 0.15–0.20 0.22–0.24 Composite 45 N, NC, SC, S

OKNA Windows & Doors (Casement Windows)

Product Line CPD Number U-Factor SHGC Frame Type PG Climate Zones
Casement – 700 Series OKW-K-26 0.16–0.20 0.22–0.24 Vinyl 70 N, NC, SC, S

OKNA Windows & Doors (Picture Windows)

Product Line CPD Number U-Factor SHGC Frame Type PG Climate Zones
Insul Tec – 510 / 5510 Series OKW-K-19 0.14–0.20 0.24–0.27 Vinyl 75 N, NC
Precision Weld – 410 Series OKW-K-27 0.20 0.28 Vinyl 75 N, NC
Enviro Star – 810 Series OKW-K-28 0.20 0.27 Vinyl 75 N, NC

OKNA Windows & Doors (Sliding Windows)

Product Line CPD Number U-Factor SHGC Frame Type PG Climate Zones
Insul Tec – 520 / 5520 Series OKW-K-21 0.16–0.20 0.23–0.26 Vinyl 40 N, NC
Precision Weld – 420 Series OKW-K-24 0.17 0.25 Vinyl 35 N, NC, SC, S
Enviro Star - 820 Series OKW-K-30 0.20 0.25 Vinyl 50 N, NC, SC, S
Starmark - 920 Series OKW-K-33 0.15–0.20 0.22–0.25 Composite 40 N, NC, SC, S