U-values · checked 3 November 2026
Triple glazing and the window grant
Every new window and door needs a U-value of 1.4 W/m²K or lower. Triple glazing is only needed facing north. Here's what to ask for in the quote.
Figures checked against MyHome and seai.ie on 3 November 2026.
windowgrants.ie is not SEAI or a government body and does not award grants.
- €4,000 detached, €1,800 mid-terrace, €1,500 apartment
- Plus €800 per door, up to two
- One SEAI-registered contractor rings you
Only for north-facing windows. Under the SEAI windows and doors grant, every new window and door must reach a U-value of 1.4 W/m²K or lower, and windows facing north must be triple glazed. Double glazing is enough on the other sides.
That's the standard as reported by MyHome on 4 March 2026. The 1.4 figure is also in the Irish Examiner on 24 March, quoting SEAI, and West Cork People in April. SEAI's own grant page doesn't print a U-value: its test is the home's heat loss after the work (seai.ie, checked 3 November 2026).
Do I need triple glazing for the window grant?
Only on north-facing windows. MyHome's summary of the scheme rules says: "Triple glazing must be fitted on north-facing windows; minimum double glazing is required for all other windows" (MyHome, 4 March 2026). The other reports we checked give the 1.4 W/m²K figure but don't mention the north-facing rule, so ask the contractor to confirm it against SEAI's current terms.
What U-value do the windows need?
1.4 W/m²K or lower, for windows and doors alike (MyHome, 4 March 2026; Irish Examiner, quoting SEAI; West Cork People, April 2026). A U-value measures how fast heat passes through: lower is better. Ask the contractor for the U-value of each window and door in writing, for the whole unit, frame included.
| Glazing | U-value (W/m²K) | Meets the grant? |
|---|---|---|
| Single glazing | 4.0 or more | No |
| Older double glazing | 2.5 to 4.0 | No |
| Newer double glazing | 1.6 to 2.5 | No |
| Good double glazing | 1.4 or lower | Yes, except facing north |
| Triple glazing | 1.4 or lower | Yes, on any side |
The glazing bands are the ones we use for SEAI's BER register on this site. The 1.4 W/m²K standard: MyHome, 4 March 2026, Irish Examiner, West Cork People, April 2026. The north-facing rule: MyHome, 4 March 2026.
How far off are the windows in Irish homes now?
A long way. On BER certificates for homes built before 2011, the median window U-value is 2.71 W/m²K. 7.3% are still single glazed and 58% have older double glazing at 2.5 or worse. Only 5% already have windows at 1.6 or better (SEAI's BER register, 751,617 certificates).
| Glazing (U-value) | Share of certificates |
|---|---|
| Single glazing (4.0 or more) | 7.3% |
| Older double glazing (2.5 to 4.0) | 58% |
| Newer double glazing (1.6 to 2.5) | 30% |
| 1.6 or better | 5% |
Source: SEAI BER Research Tool, the full public file downloaded 29 October 2026: 751,700 certificates for existing homes built before 2011, leaving out the BERs done for grant claims. Bands are ours.
Is triple glazing worth it on every side?
The grant doesn't pay more for it: SEAI pays a fixed amount by home type, €1,500 to €4,000, whatever glazing you pick (seai.ie). Triple glazing costs more and is heavier. Good double glazing at 1.4 or lower meets the standard on the east, south and west. Ask for a price both ways, with the U-values, and decide on the difference.
Do frames matter?
None of the sources above names a frame material. The standard is the U-value of the finished window, so uPVC, aluminium and timber can all meet it if the whole unit reaches 1.4 W/m²K or lower.
The test that decides the grant
New windows alone don't secure the grant. After the work, the home's BER advisory report must show Good or Very Good heat loss, and an HLI below 2.3 meets it (seai.ie). A post-works BER is needed to claim (West Cork People, April 2026). How the heat loss test works.
FAQ
Glazing questions
Do I need triple glazing for the SEAI grant?
Only on north-facing windows. All new windows and doors need a U-value of 1.4 W/m²K or lower; double glazing is allowed on the other sides, as reported by MyHome on 4 March 2026.
What U-value do windows need for the grant?
1.4 W/m²K or lower, for windows and doors.
Does triple glazing get a bigger grant?
No. The grant is a fixed amount by home type, €1,500 to €4,000, whatever the glazing.
Do aluminium windows qualify?
The standard is the U-value of the whole window, not the frame material. An aluminium window that reaches 1.4 W/m²K or lower meets it.
Does SEAI's page give the U-value?
No. SEAI's windows and doors page sets the heat loss test on the BER instead. The 1.4 W/m²K figure is from SEAI as quoted by the Irish Examiner, and the north-facing rule from MyHome's summary, both March 2026.
Your grant
Your window grant in 3 taps
Tap your home type, when it was built and what you're replacing. Your SEAI grant shows as you go. Then leave your number and one SEAI-registered contractor who covers your area rings you with a price.
Where these numbers come from (4 public sources, checked 3 November 2026)
Sources (1)
Prices and facts on this page were checked against these published pages. We are not connected to these businesses.
- West Cork People: westcorkpeople.ie