Hy-Lite Glass Block Window 5×5: Pre-Fabricated Privacy Without the Mortar

Hy-Lite’s 5×5 glass block window (41-1/4” × 41-1/4” rough opening) delivers real glass block privacy without the traditional installation headaches. The completely prefabricated unit arrives ready to install with a nail-fin frame — no mortar mixing, no block-by-block assembly, no mason required.

At 117 pounds, the window runs 25% lighter than conventional glass block construction, which matters when crews are hauling units up ladders or positioning them for upper-story installations. The frame-based installation uses standard silicone caulk instead of mortar, cutting installation time from hours to minutes.

Thermal Performance and Weight Specifications

The window achieves a U-factor of 0.51 (approximately R-1.96), matching the energy performance of double-insulated glass. That’s adequate for Montana’s Climate Zone 6 requirements when combined with proper wall insulation. The thermal performance comes from vinyl spacers between blocks that break thermal bridging while maintaining the traditional mortared appearance.

The 2-inch thick blocks use thinner and lighter glass than standard block, contributing to the weight reduction without sacrificing durability. Size options range from the compact 3×3 to the larger 6×6:

Size	Rough Opening	Actual Size	Weight
3×3	25-1/2” × 25-1/2”	25” × 25”	44 lbs
4×4	33-1/2” × 33-1/2”	33” × 33”	77 lbs
4×5	33-1/2” × 41-1/4”	33” × 40-3/4”	96 lbs
5×5	41-1/4” × 41-1/4”	40-3/4” × 40-3/4”	117 lbs
6×6	49-1/4” × 49-1/4”	48-3/4” × 48-3/4”	168 lbs

Frame Options and Installation Details

Contractors can choose between thermally-broken aluminum frames (available in white or tan painted finishes) or vinyl frames (white and tan). Both options include nail fin offset choices of 7/8” or 1-3/8” to accommodate different wall thicknesses and siding applications.

The nail-fin installs directly into the prepared rough opening, with silicone applied along the spacer lines for a traditional mortared look. The system works with standard wood, vinyl, or aluminum framing in both residential and commercial construction. White silicone caulk comes included to complete the mortar-line appearance.

The pre-assembly eliminates several traditional glass block installation challenges. No mixing ratios to calculate. No cleanup of excess mortar. No waiting for mortar to cure before moving to the next construction phase. Reviews consistently praise the ease of installation in bathroom remodels.

Who Should Consider This Window

Bathroom and basement applications dominate the use cases. The clear wave pattern (with ice and other patterns available) provides privacy while transmitting natural light — solving the classic bathroom window dilemma. The thermal performance works for heated spaces, though unheated garages or workshops might benefit from lower U-factor alternatives.

The weight reduction matters most for remodelers working solo or with small crews. At 117 pounds for the 5×5, one strong installer can manage the unit. Traditional glass block construction of the same size would require multiple workers or mechanical assistance.

Hy-Lite backs the windows with a 10-year limited warranty. AAMA and NFRC certifications confirm third-party testing of the performance claims.

Frequently Asked Questions

How does the U-factor compare to triple-pane windows?

At 0.51 U-factor, these windows match double-pane performance but fall short of triple-pane units that typically achieve 0.20-0.30. The privacy benefit often outweighs the thermal difference for bathroom applications.

Can these windows be used in shower enclosures?

While suitable for bathrooms and designed for easy installation with silicone caulk, the windows work with standard residential and commercial framing. Direct water exposure applications would require additional waterproofing measures.

What’s the actual time savings versus traditional block installation?

The pre-fabricated unit with nail-fin installation eliminates mortar work entirely. A window that might take 4-6 hours with traditional block-by-block mortar installation can be completed in under an hour.

Do the vinyl spacers affect the appearance?

The vinyl spacers between blocks maintain the traditional mortared look, especially after silicone is applied along the spacer lines. From normal viewing distances, the window appears identical to traditional glass block.

How does the weight compare for different frame materials?

The 5×5 unit weighs 117 pounds regardless of choosing aluminum or vinyl frames. The frame material choice affects thermal performance and cost more than weight.