Description
Twin Double Hung Window Features
Our twin double hung windows combine historic craftsmanship with modern engineering, featuring dual operable sashes designed for enhanced functionality. Built with vertical-grain Douglas fir or thermally modified ash frames (1.75″ thickness, ASTM D1037 compliant), these units deliver:
Precision airflow control – Open both sashes simultaneously for 38 CFM ventilation capacity
Thermal optimization – Triple weatherstripping achieves U-factor 0.28 (exceeds ENERGY STAR® by 15%)
Structural integrity – Mortise & tenon joinery withstands 150 PSF wind loads (ASTM E330 certified)
Technical innovations include:
True divided lite – 7/8″ wood muntins replicate historic profiles (National Park Service compliant)
Smart counterbalance – Spring-loaded mechanism supports 40 lb sash weight for single-finger operation
Hybrid glazing – Choose between 92% VLT clear glass or Low-E coating (SHGC 0.24)
Benefits of Twin Double Hung Windows
1. Climate-Adaptive Ventilation
Stack ventilation – Open upper/lower sashes creates chimney effect airflow, reducing cooling costs by 18%
Humidity control – 45° tilt-in function prevents condensation buildup in 80% RH environments.
2. Architectural Authenticity
Period-accurate details – 12-over-12 grille patterns match Victorian/Colonial façades
Material continuity – FSC-certified woods maintain original home character in preservation zones.
3. Maintenance Efficiency
Full-access design – Removable sashes enable exterior cleaning from indoors (no ladder required)
Self-lubricating tracks – PTFE-impregnated channels maintain smooth operation for 25+ years.
4. Energy-Smart Construction
Thermal break – Aerogel-insulated frame cavities reduce heat transfer by 41%
Air infiltration <0.15 CFM – Compression seals outperform standard double hung windows.
5. Customization Versatility
Stain matching – 60+ custom tints replicate historic wood patinas (Munsell Color System)
Hybrid configurations – Pair with fixed transoms for light/ventilation balance.
