Passive House & High-Performance Fiberglass Products
Inline Fiberglass builds fiberglass windows and doors for projects where thermal performance, durability, comfort, and technical documentation matter.
Built for Projects Where Performance Is Not Optional
Passive House and high-performance buildings place more demand on windows and doors than standard projects. Frames, glass packages, spacers, air-tightness, installation details, and product selection all affect the final result.
Inline Fiberglass supports performance-focused projects with fiberglass window and door systems designed for long-term stability, thermal comfort, and clean architectural design.
This page helps you understand which Inline products may fit your project, what documentation to request, and how to connect with the right technical support before specifying or ordering.
Tested and Confirmed to Perform
Our windows and doors meet the rigorous standards of Passive House , Phius & Energy Star certification, ensuring superior energy efficiency and comfort in your home. Designed to minimize energy consumption, they provide a sustainable solution for modern living.
Passive House Certification
Our windows and doors are Energy Star certified, ensuring they meet strict energy efficiency guidelines set by the EPA. This certification helps you save on energy bills while contributing to a healthier environment.
PHIUS Certification
Inline Fiberglass products are certified by PHIUS, guaranteeing that they adhere to the highest performance standards for energy efficiency. This certification reflects our commitment to sustainable building practices and quality craftsmanship.
Energy Star Certification
Our windows and doors are Energy Star certified, ensuring they meet strict energy efficiency guidelines set by the EPA. This certification helps you save on energy bills while contributing to a healthier environment.
400 Series Fixed / Strip Windows
For architectural projects that need large fixed openings, clean sightlines, and strong thermal performance, the 400 Series Fixed / Strip window pathway should be reviewed early in the specification process.
Best suited for:
Large fixed glass areas, commercial projects, modern homes, Passive House and high-performance designs, and projects where fixed units carry much of the building envelope strategy.
600 Series Sliding Patio Doors
The 600 Series Sliding Patio Door supports high-performance projects that need large glass openings, outdoor access, and Energy Star Most Efficient performance when specified with triple glazing.
Best suited for:
Patios, terraces, modern homes, custom builds, high-performance residential projects, and energy-conscious door applications where the correct glazing and performance documents are confirmed.
Other Fiberglass Window Systems
Inline also offers fiberglass window systems for different design and operating needs. For this page, promote PHIUS-certified 325 Series casement/awning/fixed, 400 Series, and 3000 Series tilt & turn/fixed first.
For Passive House or high-performance work, the correct product should be reviewed against the project’s performance targets before being selected.
Certifications, Testing & Performance Documentation
Explore the certifications, testing programs, and technical resources that support Inline fiberglass windows and doors.
Phius / Passive House
PHIUS-certified product pathways include 325 Series casement, awning, fixed, 400 Series, and 3000 Series tilt & turn/fixed.
NFRC Performance
All Inline products have current NFRC listings. Thermal and optical performance information can support product comparison and specification decisions.
AAMA Testing
All Inline products have current AAMA ratings that support structural and operational confidence.
Energy Star
325, 400, 600, and 3000 Series products reach Energy Star Most Efficient when specified with triple glazing.
IGMAC-Certified Glass
All Inline products use IGMAC-certified glass units, supporting long-term glass performance and moisture resistance.
EPD & Sustainability
Inline has Environmental Product Declaration documentation available for sustainability-focused projects and specification teams.
How Inline Supports Passive House and High-Performance Projects
High-performance projects need more than a product brochure. They need the right product path, the right glass package, and the right documentation. Inline can support project teams with:
Product Selection Guidance
Help reviewing which fiberglass window or door series may fit the project’s performance, design, and operating needs.
Performance Documentation
Access to available product data, certification references, NFRC data, technical documents, and related resources.
Select Glass Package Options
Guidance on double-pane, triple-pane, Low-E, spacer, gas-fill, and other glass package considerations where applicable.
Architect and Builder Support
Support for specifiers, builders, and project teams that need technical clarity before quoting, specifying, or ordering.
High-Performance Project Fit
High-Performance Project Fit
Support for Passive House, PHIUS, energy-efficient, custom residential, and commercial project needs.
Project-Specific Configuration Support
Assistance reviewing options and product combinations to help align performance goals with project requirements.
Why Fiberglass Works for High-Performance Buildings
Fiberglass is a strong fit for performance-focused window and door systems because it supports:
Thermal Performance
Fiberglass helps reduce frame-related heat transfer compared with more conductive materials.
Dimensional Stability
Fiberglass expands and contracts at a rate closer to glass, helping support long-term seal and frame stability.
Strength for Larger Openings
The strength of fiberglass can support larger glass areas and clean sightlines without relying on bulky frame profiles.
Lasting Durability
Fiberglass is built for long-term performance across changing temperatures and demanding buildings.
Design Flexibility
Inline fiberglass products can support residential, commercial, modern, and traditional design goals.
Energy-Efficient Compatibility
Supports advanced double- and triple-pane glass packages for improved comfort and energy performance.
Common Project Applications
Passive House Homes
For homeowners, architects, and builders targeting high levels of energy efficiency and comfort.
Custom Residential Projects
For new builds and major renovations where windows and doors are part of the performance strategy.
Commercial and Institutional Buildings
For project teams that need durable fiberglass fenestration and technical documentation.
Energy-Efficient Renovations
For homeowners upgrading older windows and doors with long-term comfort and durability in mind.
Large Glass Openings
For designs that require stronger frame material, larger openings, and improved thermal control.
Common Questions About Passive House & High-Performance Products
Find clear answers to common questions about Passive House & High-Performance Products , including product options, performance considerations, and how to choose the right solution for your project.
Which Inline products are PHIUS or Passive House certified?
PHIUS-certified product pathways include 325 Series casement/awning/fixed, 400 Series, and 3000 Series tilt & turn/fixed. The 3000 Series tilt & turn/fixed is also confirmed as PHI certified.
Are all Inline windows Passive House certified?
No. The confirmed PHIUS-certified product pathways are 325 Series casement/awning/fixed, 400 Series, and 3000 Series tilt & turn/fixed. The 3000 Series tilt & turn/fixed is also PHI certified.
Do Inline products qualify for Energy Star?
Energy Star applies to all triple-glazed Inline products and some double-glazed products. Inline confirms that 325, 400, 600, and 3000 Series products reach Energy Star Most Efficient when specified with triple glazing.
Can Inline support Passive House window specifications?
Yes. Inline can support Passive House and high-performance projects with product guidance, technical documents, performance data, and spec support. Project teams should submit the project type, location, product interest, and performance requirements.
Do you provide drawings and technical documents?
Inline can provide available product specs, drawings, performance documents, certification references, and related technical resources upon request.
Can homeowners buy Passive House windows?
Inline can provide available product specs, drawings, performance documents, certification references, and related technical resources upon request.
What makes fiberglass useful for high-performance windows?
Fiberglass supports strength, dimensional stability, thermal performance, durability, and clean design. That makes it a strong material choice for projects where the window or door system has to support long-term envelope performance.
Do Passive House windows cost more than standard windows?
High-performance products often involve more advanced glass packages, tighter performance requirements, and more technical coordination. Inline should provide project-specific quotes instead of publishing broad pricing claims.
Can Inline help with commercial high-performance projects?
Yes. Inline supports residential, commercial, architectural, and high-performance project needs. Commercial teams should request product data, project support, and technical review early in planning.
Planning a PHIUS, Passive House, or High-Performance Project?
Get the product information you need before you specify, quote, or order. Inline can help you review PHIUS-certified product pathways, Energy Star configurations, public technical downloads, EPD resources, and high-performance fiberglass window and door options for your project.
Tell Us About Your Passive House, or High-Performance Project
Our team will review your request and help you confirm the right next step.
We respect your privacy and will only use your details to respond to your request.