Passive House window selector
Answer four questions on climate, target U-value, opening type and project size. The engineering assistant matches the project to an F1 FRP window series, explains the role of PHI Component-ID 2491wi03 and points to the calculation and project references.
- PHI component
- 2491wi03
- Efficiency class
- phB
- Climate zone
- Cool-temperate
Enter the project target. Whole-window performance depends on dimensions, glazing, spacer and frame configuration.
How the selector works
Step 1
Define the thermal context
Choose the PHI climate class and the target whole-window U-value, so the recommendation starts from the right performance envelope rather than a generic frame claim.
Step 2
Add the opening configuration
Select casement, tilt-turn, sliding or fixed facade. The configuration narrows the practical range across the 65, 70, 80, 90 and 140 series.
Step 3
Review the evidence and next steps
The answer gives a series recommendation, the certification context, a comparable project and a path to U-value calculation, drawings, fabrication review and quotation.
It organizes early inputs before a detailed EN ISO 10077 calculation or a project-specific review, for architects, facade consultants, window fabricators, energy modelers and procurement teams comparing frame depths and certification evidence at concept or tender stage.
Why FRP instead of thermally broken aluminum
Thermal bridging
An FRP frame has no metal path through it. Pultruded GFRP conducts about 0.3 W/m·K, against about 52 for steel and 160 for aluminum, so there is no thermal break insert to rely on.
PHI component reference
PHI 2491wi03 covers the stated 90-series configuration at efficiency class phB in the cool-temperate zone. For a project in a harsher climate, see Qinling Station in the Antarctic Ross Sea.
Color and finish
Through-colored profiles carry the pigment in the resin, so there is no applied paint layer to chip in coastal or high-altitude exposure. Coated finishes are specified separately.
Coastal exposure
FRP does not corrode in salt air the way steel and aluminum parts do. See the Yancheng Talent Apartment project on the Jiangsu coast.
Selection method and technical references
The selector uses climate class, opening type, target U-value and project scale as screening inputs. It does not calculate a certified whole-window value by itself. Whole-window performance depends on the frame U-value, glazing U-value, spacer linear transmittance, frame and glass areas and the exact test or reference dimensions; check those terms with the EN ISO 10077-1 method and confirm them for the proposed glass build, spacer, sash, hardware and installation interface.
PHI Component-ID 2491wi03 supports the certified 90-series configuration; it does not certify every project size or glazing combination. Use the certificate and published data as evidence for the matching build, and document any variation through the project’s energy model, window schedule, supplier calculation and certification process. PHI certificate (PDF)
Inputs to verify before accepting a series
Climate and certification route
Identify PHI, PHIUS, the local energy code or project-specific modeling, and the required climate or performance class, instead of treating the programs as interchangeable.
Reference size and opening type
Document the tested or calculated window dimensions, sash configuration, frame fraction, mullions, transoms, reinforcement, hardware and allowable operating size.
Glazing and spacer
Record Ug, pane build, coatings, gas fill, spacer linear transmittance, edge conditions and the supplier data used in the whole-window calculation.
Installation interface
Review the rough opening, anchors, support blocks, membranes, insulation continuity, sill drainage and the linear thermal bridge between frame and wall.
Non-thermal performance
Confirm structural wind pressure, water penetration, air leakage, acoustic target, security, fire, durability, condensation, hardware cycling and local fenestration standards.
Supply and fabrication model
State whether the project needs finished windows or pultruded lineals, who fabricates and glazes, quantity, colors, quality plan, certification labels, packing and destination.
While these inputs are open, keep the recommendation conditional. A useful concept-stage answer says the 90 series is the likely baseline, subject to an exact Uw calculation, an opening-size check, the installation detail and a review of the certificate scope. That is more defensible than presenting one nominal frame value as the performance of every finished window.
Compare the first candidate with the published 65, 70, 80, 90 and 140 series rather than treating it as the only option. Request section drawings, frame and sash dimensions, reinforcement limits, glazing range, hardware compatibility, drainage details, finishes and the certificate pages that support the proposed build. Run at least one representative window through the U-value calculator, then repeat the check for unusually small, large, subdivided or operable units, because the frame fraction and edge length change the result. Record the accepted configuration in the window schedule so later substitutions are reviewed against the same basis.
What the selector can and cannot decide
The selector can narrow the series range, explain why climate and opening type matter, locate the relevant certification and case-study evidence and prepare the questions for a supplier review. It cannot replace a certified U-value calculation, structural and hardware verification, condensation analysis, airtightness detailing, a local code review or approval by the project’s responsible professional.
Treat the output as an auditable selection brief: verify every stated input, keep the calculation record, confirm the exact frame and glazing build, and request the drawings, certificate scope, test reports, lead time, packing and commercial terms that apply to the project.
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Send the window schedule for a series recommendation
Send the climate, target U-value, window types and sizes, quantities and whether you need finished units or profiles. We reply within one business day.