What does NFRC certification actually tell me?
It tells you the whole product — frame and glass together — was measured by an accredited laboratory under one standard procedure, and that the result is published in the NFRC Certified Products Directory under a CPD number. It is not a centre-of-glass figure, and it is not an ENERGY STAR award.
Why the whole-product part is the whole point
A centre-of-glass figure measures the glass and quietly omits the frame. On an aluminum window the frame is exactly where performance is won or lost, so a centre-of-glass number answers a different question from the one a plan checker is asking. An NFRC rating covers the assembled product.
That is also why an NFRC rating cannot be argued with at plan check: it is a public record, not a supplier claim.
What is in a certified record
A CPD record covers a series and an operator type, and lists every certified configuration within it. Our product pages publish the CPD number beside the rating so the figure can be checked without contacting us.
| Field | What it means |
|---|---|
| CPD number | The directory identifier, e.g. DRN-M-8. Search it at nfrc.org. |
| U-factor | Whole-window heat transfer, in Btu/h·ft²·°F. Lower is less heat loss. |
| SHGC | Solar heat gain coefficient. Lower admits less solar heat. |
| VT | Visible transmittance. Higher is more daylight. |
| CR | Condensation resistance. Higher resists condensation better. |
| Operator type | Fixed, casement, tilt and turn, sliding door and so on — certified separately. |
The factory registers a separate CPD record per sash configuration, so a fixed lite and an operable lite in the same platform have different numbers and different ratings.
What an NFRC number does not tell you
It is not an ENERGY STAR certification. ENERGY STAR is awarded model by model and climate zone by climate zone against these tested ratings, by EPA-recognised certification bodies.
It is not a structural or impact rating either. Design pressure, forced-entry resistance and hurricane impact are separate test regimes with separate reports.
Where a product of ours has a CPD record, we publish the certified figures and drop the catalogue energy numbers rather than showing both — a specifier should not have to guess which one belongs on a submittal. Where we hold no certified data, the row is left blank rather than estimated.
Source: NFRC Certified Products Directory records transcribed into lib/nfrc-config.ts; CPD numbers are published on the relevant product pages.
Other questions
- How long do imported aluminum windows take to arrive in the US?
- What U-factor do I need for my climate zone?
- What is a thermal break, and does it matter?
- Tilt and turn or casement: which should I specify for a US project?
- Can imported windows meet Florida HVHZ requirements?
- What documentation should a window supplier give me?
- Can a large window opening ship as one assembly?
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