Predictable Energy Efficiency, or the NFRC Certification
The NFRC certification is a recommended document to consider when choosing windows for export to the United States. You can include this certification, but it is not mandatory.
What does this particular classification refer to?
The NFRC defines the performance of windows and doors. Tests carried out for certification purposes give results in the following categories:
- U-value (heat transfer),
- SHGC (Solar Heat Gain Coefficient: solar radiation transmittance),
- VLT (Visible Light Transmittance): air permeability and resistance to condensation.
Thus, NFRC informs whether a window meets American standards, such as Energy Star and Energy Code. Adhering to NFRC certification methods is essential to meet these standards.
Parameters Allowed by Energy Star
In countries like the USA and Canada, the parameters within the Energy Star framework are as follows:
- Uw: ≥1.53
- U-Factor: ≥0.27
- SHGC: any
Differences in Categories Between European and American Windows
- Heat Transfer Coefficient. Uw - European version; U-value - American version.
- Solar Radiation Transmittance. SHGC - American version; g - European version.
- Visible Light Transmittance. Lt - European version; VLT - American version.
Other Factors in Window Selection
R-Value
Another parameter to pay attention to when considering European windows imported to the USA is the R-Value (heat resistance coefficient). The higher it is, the better the window resists heat flow. For modern triple-glazed windows, the R-Value typically ranges from 3 to 5.
You might ask: What is the difference between R-Value and U-Factor? Both values are used to determine the thermal efficiency of a window. The difference is that the U-Factor focuses on heat transfer through the window and uses scientific calculations to measure this phenomenon. This is important for evaluating thermal performance. R-Value, on the other hand, focuses on the insulating ability of the specific material used in the window. It measures how effectively this material reduces heat exchange between the interior and the outside. The higher the R-Value, the better the thermal insulation.
Air Permeability
Air permeability is a measure that indicates how much air passes through the gaps in a window unit.
The UNE-EN-1026 standard used in Europe classifies the air permeability of windows into four classes: from 1 to 4. The more airtight the window (class 4), the better it retains heat inside the room. However, higher airtightness can make natural ventilation more difficult, which should be considered when designing and using windows.
In the USA, the Air Leakage (AL) parameter corresponds to the air permeability of windows, similar to the classification used in Europe. It is measured on a scale from 0.1 to 0.3, with a lower value indicating better airtightness.
STC
American windows may also be described by the STC number, or Sound Transmission Class. This indicates how well a window reduces airborne sound transmission.
European Windows for the American Market. Offering from Distributors
The most renowned suppliers offer many window models that are perfectly suited for installation in the United States. They meet all the compliance parameters mentioned above with ease.
It is worth collaborating with companies like EUROCOLOR to ensure that importing window joinery from Poland to the USA and Canada goes smoothly.
