High-performance glazing retrofit for existing buildings: the glass changes, the frames stay.
- Building modernization without full façade replacement
- Performance limitations of legacy glazing systems
- Enthermal® vacuum insulating glass
- Centre-of-glass thermal resistance comparison
- Enthermal® in retrofit application
- Whole-system considerations
- Retrofit implementation strategy
- Capital comparison: retrofit vs full façade replacement
- Operational energy impact
- Integrated retrofit delivery model
- Initiate a retrofit evaluation
Building modernization without full façade replacement
Glass Only Replacement (GOR) covers insulated glass units (IGU) and vacuum insulated glass (VIG). This page describes the VIG route: the existing glazing units are replaced with LuxWall Enthermal® vacuum insulating glass inside the existing aluminum frames.
Glass-only retrofit enables performance modernization without full façade removal. Installation can be sequenced floor-by-floor or elevation-by-elevation, minimizing operational disruption.
Dura Seal supplies LuxWall Enthermal® vacuum insulating glass for glass-only retrofit and leads its delivery; installation is by local glazing partner crews in major markets together with Dura Seal's own crews.
Performance limitations of legacy glazing systems
Across British Columbia's existing building stock, legacy glazing systems continue to represent one of the most significant constraints to overall building envelope performance.
Single-pane assemblies and early-generation dual-pane insulated units remain prevalent across commercial, institutional, and multi-residential assets, many installed prior to modern energy performance standards.
As regulatory requirements, decarbonization targets, and energy performance expectations evolve, these glazing systems present measurable limitations to building efficiency, occupant comfort, and long-term asset resilience.
Key technical challenges
- Low centre-of-glass thermal resistance
- All three modes of heat transfer (convective, conductive, radiative) through glazing assemblies
- Thermal bridging at framing interfaces
- Seal degradation and gas loss in aging IGUs
- Elevated condensation risk under interior humidity loads
Enthermal® vacuum insulating glass
LuxWall's Enthermal® replaces the air or gas-filled cavity of a conventional insulating unit with a vacuum chamber. Convective heat transfer is eliminated and conduction is significantly reduced, enabling centre-of-glass insulation performance historically associated with opaque wall assemblies while maintaining transparency.
Engineered for retrofit integration, Enthermal® units provide a high-performance upgrade solution without requiring full window or façade replacement.
The unit is two tempered lites with a 0.25 mm vacuum cavity, 8 to 12 mm in total. Centre-of-glass U-factor as low as 0.30 W/m²·K (0.055 BTU/hr·ft²·°F, R-18), LuxWall-published for the triple-silver low-e build.
LuxWall, Inc. is headquartered in Ypsilanti, Michigan, and manufactures in Michigan.
Inside an Enthermal® unit
- Evacuation port
- Clear tempered glass
- Structural micro-pillars
- Thin film getter
- Hermetic edge seal
- Triple-silver low-e tempered glass
Centre-of-glass thermal resistance comparison
Comparative conductive heat transfer across conventional and vacuum insulating glazing assemblies.
| Glazing configuration | R-value | U-factor (W/m²·K) | U-factor (BTU/hr·ft²·°F) | Overall unit thickness |
|---|---|---|---|---|
| Double pane, low-e argon | about R-4 | 1.4 | 0.25 | 24 to 28 mm |
| Triple pane | R-7 to R-9 | 0.6 to 0.8 | 0.11 to 0.14 | 36 to 44 mm |
| Enthermal® | R-18 | as low as 0.30 | 0.055 | 8 to 12 mm |
| Enthermal Plus™ | R-23 | as low as 0.24 | 0.043 | 25 mm |
- Centre-of-glass values for Enthermal® and Enthermal Plus™ are LuxWall-published, calculated with LBNL WINDOW 7 for the best-coating builds; they vary with coating and configuration. Double pane and triple pane values are typical category values, not named products.
- Whole-window performance depends on the frame and is confirmed per project.
- LUXWALL® and ENTHERMAL® are registered trademarks of LuxWall, Inc., used under licence. Enthermal Plus™ is a trademark of LuxWall, Inc.
Enthermal® in retrofit application
High-performance upgrade within existing frame depth
Enthermal® achieves up to 4 to 5 times the centre-of-glass thermal resistance of a low-e argon double unit (U 1.4 W/m²·K) while maintaining existing aluminum frame geometry.
What stays
- Existing aluminum frame, undisturbed
- Maintains existing mullion sight-lines
- No increase in glazing pocket depth
- Reduced dead load compared to triple glazing
Pocket depth by product
- Enthermal® (8 to 12 mm): monolithic and thin glazing pockets. In a standard 1-inch insulating glass pocket it is set with adapter gaskets and setting blocks.
- Enthermal Plus™ (25 mm hybrid unit): standard 1-inch insulating glass pockets.
- Feasibility is confirmed by a frame survey: pocket depth, bite, edge cover, seals.
- Final compatibility subject to frame system review and structural verification.
Glass-only retrofit in the existing frame
Existing glazing assembly: conventional low-e argon dual pane within aluminum framing, about R-4 centre-of-glass
Retrofitted: Enthermal® within the same frame, R-18 centre-of-glass, LuxWall-published
- Existing dual pane unit (removed)
- Enthermal® vacuum insulating glass
- Structural silicone (as required)
- New gasket profile
- Setting block
- Existing aluminum frame (undisturbed)
Interior surface temperature
Centre of glass, at 21 °C inside and −20 °C outside:
Low-e argon double, U 1.4 W/m²·K
13.8 °C
Interior glass surface
Exterior −20 °CInterior 21 °C
Enthermal®, U 0.30 W/m²·K
19.5 °C
Interior glass surface
Exterior −20 °CInterior 21 °C
- Dew point 4.6 °C at 21 °C and 35 % relative humidity: both centre-of-glass surfaces sit above it.
- Calculated, not measured: interior surface temperature = indoor temperature − U × (indoor − outdoor) ÷ interior film coefficient, with an interior film coefficient of 8 W/m²·K and centre-of-glass U-factors.
- Condensation first appears at the edge of glass and at the frame, so it is checked at the actual edge detail for each project.
Whole-system considerations
Whole-window performance reflects combined glazing and frame thermal interaction.
Every thermal value on this page is a centre-of-glass value. In aluminum framing the frame and the edge of glass, not the glass, set the whole-window U-factor.
A whole-window value belongs to the frame it is modelled in, so none is quoted here. Whole-window values are modelled per project to CSA A440.2 / NFRC 100.
- Centre-of-glass
- About R-4 for a low-e argon dual unit; R-18 for Enthermal®, LuxWall-published.
- Frame
- The existing aluminum frame, unchanged by a glass-only retrofit.
- Whole window
- Dependent on frame condition, glazing ratio, and installation detailing; modelled per project.
01Heat flow redistribution
- Increasing centre-of-glass resistance reduces heat flux through vision area
- Overall heat transfer shifts toward framing members through lateral conduction
- System heat flow distribution changes as glazing performance increases
02Frame influence
- Existing aluminum framing remains thermally conductive
- Frame-to-glass ratio influences final whole-window U-factor
- Edge conditions and spacer performance affect perimeter heat transfer
03Retrofit implications
- Glass-only retrofit improves whole-window thermal performance; by how much depends on the frame
- Frame thermal bridging is not eliminated
- Frame condition should be evaluated in conjunction with glazing upgrade
System-level retrofit implications
01Structural continuity
- Existing structural anchorage remains undisturbed
- No modification to perimeter attachment systems
- Load paths remain unchanged following glazing retrofit
02Envelope integration
- Air and vapour barrier interfaces remain intact
- Adjacent cladding systems are not disrupted
- Existing drainage and water management strategies are maintained
03Retrofit implementation efficiency
- Glazing replacement executed within existing frame geometry
- Reduced construction sequencing complexity
- Minimal impact to interior finishes and building operations
- Final compatibility subject to frame system review and structural verification.
Glass-only retrofit enables high-performance thermal improvement while maintaining structural and envelope continuity.
Retrofit implementation strategy
Phased façade modernization within occupied building environments
01Installation phasing
- Work executed from swing stage, rope access, or interior access
- Floor-by-floor or vertical stack sequencing achievable
- Minimal tenant decanting required
02Construction disruption profile
- No removal of primary framing systems
- Reduced demolition and material handling
- Limited interior protection required
03Schedule compression
- Accelerated cycle times vs full window replacement
- Parallel fabrication and installation sequencing
- Reduced overall project duration
Capital comparison: retrofit vs full façade replacement
Relative capital investment required for vision glazing modernization
- 30 to 40 %Typical capital investment for glass-only retrofit, relative to full façade replacement
- 60 to 70 %Approximate cost avoidance
Estimate by the Dura Seal estimating team. Typical range, not a guarantee.
01Capital investment profile
- Lower upfront capital requirement
- Avoids structural demolition and replacement
- Simplified engineering scope
02Construction cost drivers
- Eliminates full façade demolition and disposal
- Avoids structural reframing and slab edge reconstruction
- Reduces swing stage duration and access requirements
- Minimizes interior protection and tenant coordination
- Limits trade stacking and envelope sequencing conflicts
03Capital efficiency
- Avoids full curtain wall replacement cost
- Leverages existing structural framing assets
- Enables phased capital deployment
04Life cycle capital planning
- Defers full façade replacement capital horizon
- Enables phased retrofit aligned with reserve fund planning
- Improves energy performance and operating cost profile
- Preserves capital for complementary asset upgrades
05Asset value enhancement
- Modernizes façade appearance
- Extends service life of existing envelope systems
Operational energy impact
Modelled performance improvements following high-performance glazing retrofit
- 15 to 30 %Modelled reduction in building energy use intensity (EUI)
Estimate by the Dura Seal estimating team. Modelled performance based on cold-climate, heating-dominant conditions with 40 to 60 % commercial glazing ratios. Typical range, not a guarantee.
Estimated savings and payback by glazing configuration
| Glazing configuration | Energy savings | Retrofit payback |
|---|---|---|
| Double pane, low-e argon | 10 to 20 %Dura Seal estimating team | 10 to 15 yearsDura Seal estimating team |
| Triple pane | 15 to 20 %Dura Seal estimating team | 8 to 12 yearsDura Seal estimating team |
| Enthermal® | up to 50 %LuxWall reports, against single pane | 3 to 10 yearsLuxWall reports |
| Enthermal Plus™ | up to 50 %LuxWall reports, against single pane | 3 to 10 yearsLuxWall reports |
- Double and triple pane figures are the Dura Seal estimating team's typical ranges by glazing configuration. The Enthermal® figures are LuxWall's published maxima against single-pane glazing; LuxWall does not publish the method. The rows are not on a common baseline: a project energy model sets the figure for a specific building. Typical range, not a guarantee.
- Actual performance may vary based on framing conditions and installation configuration, climate zone, and HVAC system efficiency.
LuxWall reports energy use cut by up to 50 % against single-pane glazing, and payback of 3 to 10 years for glass-only retrofits. Both are LuxWall's published figures, not Dura Seal's; actual savings and payback depend on the building, its climate and energy prices.
Operational energy reduction
- Reduced conductive heat transfer through vision glazing assemblies
- Warmer interior surface temperatures reduce perimeter heating demand
- Lower peak heating loads during winter design conditions
Mechanical system impact
- Improved thermal zoning stability
- Whether perimeter heating can be reduced or removed is a project-specific analysis, and savings are sized per building with an energy model.
Integrated retrofit delivery model
Retrofit success is governed as much by delivery methodology as by product performance.
Dura Seal operates as an integrated building envelope retrofit contractor specializing in façade renewal, glazing modernization, and performance-driven capital upgrades. Our teams combine technical coordination with high-rise occupied-building execution expertise to deliver constructible, low-disruption modernization programs.
Integrated retrofit project team structure
Owner
- Owner or asset management group
Consultants
- Building envelope consultant
- Mechanical or energy consultant
Delivery lead
- Dura Seal: retrofit delivery lead
Supply and access
- Access logistics
- LuxWall (glass manufacturer)
- Glazing assemblies
Installation
- Installation crews: local glazing partners and Dura Seal
Verification
- Testing and commissioning agents
- Delivery governance structure typical of high-rise envelope modernization projects.
01Retrofit project leadership
Single point of accountability from pre-construction through project closeout.
Project leadership
- Dedicated building envelope retrofit project management structure
- Integrated coordination with consultants, ownership, and asset management teams
- Direct consultant-to-contractor coordination
Pre-construction integration
- Constructibility planning within occupied building environments
- Access, sequencing, and swing stage methodology development
- Integrated design-assist support during retrofit detailing
Occupied building execution infrastructure
- Installation by local glazing partner crews in major markets together with Dura Seal's own crews
- Swing stage and access logistics specialization
- Occupied-building sequencing and safety protocols
- Quality assurance and envelope commissioning procedures
Each program is led by Dura Seal's project management team leads and its construction and quality control team leads.
Meet the team02Consultant and stakeholder coordination
Integrated communication and decision pathways supporting façade retrofit execution.
Design coordination interface
- Envelope consultant peer review of retrofit glazing design
- Thermal modelling validation against project performance criteria
- Structural interface and anchorage validation
- Mechanical consultant review of perimeter load impacts
Submittal workflow
- Shop drawings integrated with existing façade conditions
- Glazing compatibility and sightline confirmation
- Sealant, gasket, and structural silicone compatibility validation
- Manufacturer performance data submission
Construction coordination protocols
- Occupied-building phasing and access planning
- Swing stage and logistics sequencing reviews
- Interior protection and tenant coordination
- Daily field reporting and consultant review sign-offs
03Quality assurance and performance control
Installation verification and performance validation of retrofit glazing systems.
Mock-up and sample validation
- Pre-construction glazing retrofit mock-ups
- Interface detailing confirmation
- Sealant and sightline validation
- Consultant review prior to production rollout
Installation quality assurance
- Pre-installation substrate and framing inspection
- Retrofit glazing dimensional verification
- Structural silicone and gasket interface review
- Installation tolerances monitored and documented
- Field safety and access compliance inspections integrated into QA audits
Performance verification
- Air and water infiltration testing
- Thermal imaging validation
- Sealant adhesion and cohesion testing
- Field commissioning and system sign-off
Documentation and closeout
- QA reporting and photographic records
- Testing certifications and lab reports
- Envelope performance documentation
- Project closeout performance manuals
04Safety, access and risk management
Execution risk mitigation within occupied façade retrofit environments.
Access and workforce safety
- Engineered swing stage and access platform design
- Certified rigging, tie-back, and load validation
- Redundant fall protection and lifeline systems
- Daily access equipment inspection protocols
Occupied building risk controls
- Interior protection and debris containment planning
- Tenant communication and workface isolation
- Noise, dust, and vibration mitigation measures
- After-hours and phased work sequencing strategies
Installation safety governance
- Task-specific Safe Work Procedures (SWPs)
- Manufacturer handling and install compliance
- Structural glass handling and hoisting controls
- Sealant, chemical, and hot-work safety protocols
Dura Seal maintains Certificate of Recognition (COR) safety certification, reflecting independently audited safety management systems aligned with provincial construction safety standards. This framework governs workforce training, hazard identification, incident prevention, and continuous safety performance improvement across all retrofit operations.
Initiate a retrofit evaluation
A structured pathway from feasibility to implementation
Façade retrofit programs benefit from early technical evaluation to align performance objectives, constructibility constraints, and capital planning frameworks. Dura Seal and LuxWall collaborate with Building Envelope Consultants, or engage directly with your existing consulting team, to assess viable modernization pathways prior to detailed design.
Engage our team alongside your Building Envelope Consultant to evaluate retrofit feasibility, performance targets, and implementation strategy for your next façade renewal program.
This opens your email program. Or write to estimating@duraseal.ca, or call 604.472.1919.
- 01
Feasibility and performance review
- Existing façade condition assessment
- Thermal modelling and performance analysis
- Retrofit compatibility within current framing systems
- Coordination with Building Envelope Consultant
- 02
Constructibility and budget alignment
- Framing and interface condition analysis
- Occupied-building sequencing strategy
- Budget framework development
- Consultant-integrated scope validation
- 03
Implementation planning
- Mock-up and detailing coordination
- Specification alignment
- Delivery schedule development
- Field performance verification planning