Window Energy Rating in Ireland — What the Label Means and Why It Matters for BER
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Window Energy Rating (WER): A+ to E scale. The whole-window U-value is what counts for BER, not the glass alone.
Window Energy Rating (WER) in Ireland: A+ to E scale. The whole-window U-value is what counts for BER, not the glass alone. A+ rated windows: U-value 0.7–0.9 W/m²K. A rated: 0.9–1.2. B rated: 1.2–1.4. C and below: 1.4+. BER A1 needs A or A+ rated windows. Part L 2022 minimum is C (U-value 1.4). The supplier should provide a WER label for every window. The label includes: the brand, the model, the U-value, the solar heat gain coefficient, and the air leakage. Check the label before you order — it's the easiest way to compare windows across brands.
TL;DR
Window Energy Rating (WER) in Ireland: A+ to E scale. The whole-window U-value is what counts for BER, not the glass alone.
A+ rated windows: U-value 0.7–0.9 W/m²K. A rated: 0.9–1.2. B rated: 1.2–1.4. C and below: 1.4+.
BER A1 needs A or A+ rated windows. Part L 2022 minimum is C (1.4). The supplier should provide a WER label for every window.
When this matters most
You're comparing windows and need to understand the labels.
When this doesn't apply
You've already specified the windows.
Frequently asked questions
What is a Window Energy Rating (WER)?
An A+ to E scale rating of the whole window (glass + frame + spacer). The label includes: brand, model, U-value, solar heat gain coefficient, and air leakage. Required for every window in Ireland.
What WER do I need for BER A1?
A or A+. U-value 0.7–1.2 W/m²K whole-window. Part L 2022 minimum is C (1.4).
Where can I find the WER label?
On the window itself, in the supplier's brochure, or on the NSAI website. Ask the supplier for the label before you order.
Sources
NSAI, Window Energy Rating scheme. https://www.nsai.ie/
Frequently asked questions
What is a Window Energy Rating (WER)?
An A+ to E scale rating of the whole window (glass + frame + spacer). The label includes: brand, model, U-value, solar heat gain coefficient, and air leakage. Required for every window in Ireland.
What WER do I need for BER A1?
A or A+. U-value 0.7–1.2 W/m²K whole-window. Part L 2022 minimum is C (1.4).
Where can I find the WER label?
On the window itself, in the supplier's brochure, or on the NSAI website. Ask the supplier for the label before you order.
When this matters most
You're comparing windows and need to understand the labels.
When this doesn't apply
You've already specified the windows.
Where to go next
Branch into
Adjacent decisions at the same stage.