Aluminum Windows China Supplier U-Factor Unit Comparison
Put window U-factor entries into the same units before comparing numbers from a China supplier. A value written as 0.30 in US units cannot be ranked directly against 1.60 in SI units. Retain the original entry, convert a separate comparison column, then check whether the documents describe comparable windows.
Separate Product Identity from Thermal Evidence
The RGNL-100P product page identifies a thermal-break aluminum window and several opening and glass choices. Its name and profile dimensions do not establish a verified U-factor for the window in your quotation.
This comparison method is a buyer’s worksheet, not a Rogenilan rating statement. Request the actual supporting record for the proposed configuration. All numbers in the worked example below are hypothetical, not tested results, offered specifications or minimum project requirements.
Verified RGNL-100P Starting Point
| Published product fact | What remains to confirm |
|---|---|
| 100 mm system width | Actual frame and sash sections in the returned drawing. |
| 6063-T5 aluminum; 1.6 mm listed thickness | The configuration to which submitted data applies. |
| Inward, tilt-and-turn, outward and awning modes listed | Selected operation, unit size and evidence scope. |
No catalog thermal figure is adopted here. The model identity helps connect an enquiry to a product; it is not a conversion factor or proof of energy performance.
U-Factor Unit Comparison: Keep the Direction Clear
The NIST conversion table gives 5.678263 for converting BtuIT/(h·ft2·°F) to W/(m2·K). The IT subscript identifies the International Table Btu convention. Confirm the original unit definition if the source is unclear.
SI to US: divide the U-factor by 5.678263.
For the illustrative US entry, 0.30 × 5.678263 = 1.7034789, or approximately 1.70 in SI units. This is conversion of a heat-transfer coefficient, not conversion of an absolute temperature; do not add 32 or apply a temperature-only shortcut.
Keep intermediate precision in the calculation, but display the result with rounding appropriate to the source. Extra decimal places produced by multiplication are not evidence of extra measurement accuracy.
A Mixed-Unit Quotation Example
| Hypothetical source entry | SI comparison entry |
|---|---|
| Offer A: 0.30 US / I-P units as defined above |
Approximately 1.70 W/(m2·K) |
| Offer B: 1.60 W/(m2·K) |
1.60 W/(m2·K) |
The raw 0.30 is not automatically the lower thermal entry. Normalizing exposes the numerical relationship, but does not establish which offer is acceptable. The underlying assembly, measurement or calculation basis and project criteria still need review.
In a spreadsheet, retain source value, source unit, conversion direction, factor, normalized value and document reference as separate fields. Never overwrite the source cell with the converted number. A second reviewer should be able to reproduce the arithmetic from the cited document.
Same Units Do Not Mean the Same Evidence
The US Department of Energy’s window-selection bulletin distinguishes whole-unit values from center-of-glass values. Keep that distinction in the comparison: changing units does not turn a glass-only result into a whole-window result.
Record whether each submitted value concerns glass, frame or the complete assembly. Then identify its window size, opening type, frame and sash configuration, glass build-up, spacer and stated method. Ask the responsible reviewer to resolve differences instead of treating the conversion as approval.
Use three statuses: comparable for the stated review, clarification required, or missing evidence. An unlabelled number belongs in clarification required. A blank performance field is not zero, and an unresolved entry should not silently become an assumed pass.
Release a Traceable Comparison
Attach the original document and its page reference to each comparison row. If the supplier revises the glass, sash or supporting record, preserve the old row and issue a new revision. Check both the original units and normalized result again.
Do not use this worksheet to claim a certification, energy-saving percentage or local compliance. Those decisions require the applicable evidence and project review. A correct calculation can coexist with an unsuitable or unverified product submission.
Align the Quote Before Comparing Cost
A glass alternative proposed to address a thermal target can change the quoted configuration and review work. Keep product supply, requested reports or calculations, samples and delivery scope visible in the comparison. Confirm availability and cost rather than assuming a document or upgraded configuration is included.
Send the Original Data, Not Only a Target Number
- Window marks, dimensions, quantities and selected opening modes.
- Proposed glass, frame configuration and current drawing reference.
- Project target with its full units and required evidence basis.
- Original data sheets or reports, including page and revision.
- Comparison worksheet, unresolved questions and named reviewer.
U-Factor Comparison Questions
Does 0.30 always mean better than 1.60?
No. Confirm the units and evidence scope before comparing the entries. The example uses different units, not two verified product ratings.
Does converting units certify the window?
No. Conversion changes numerical expression, not certification status, test scope or suitability.
What if a quotation omits the units?
Request the original supporting document and written unit confirmation. Do not infer units from the number’s apparent size.
Is a U-factor claimed for RGNL-100P here?
No. This page supplies product identity and a comparison method, not a verified thermal rating for an order.
Make the Data Reviewable
Send Rogenilan the original thermal requirement and window schedule. Connect the RGNL-100P product to the proposed assembly, and review the Casement Windows range without assuming an unverified rating.
