This is the grant everyone's been asking about. From 2 March 2026, you can get up to €4,000 towards new windows and €1,600 for doors as a standalone SEAI grant, no need to sign up for a full deep retrofit. For a lot of homeowners with draughty single-glazed or early double-glazed windows, this is a big deal.
But there's a catch that's tripping people up: your home needs to meet a Heat Loss Indicator (HLI) of 2.3 or lower. Most people have never heard of the HLI before this grant came along, so here's the plain English version.
The only way to confirm your exact HLI is through a BER assessment. Your assessor calculates it as part of the survey and the Advisory Report tells you whether you qualify, or what insulation you need first. Don’t order windows until you know your HLI. Book a BER with Homerating.ie →
What is the HLI?
The Heat Loss Indicator is a number from the BER calculation that tells you how quickly heat escapes through your walls, roof, and floors. It's measured in watts per kelvin per square metre (W/K·m²). Lower is better.
In practical terms, 2.3 is the threshold SEAI has set to say "this house is insulated well enough that new windows will actually make a meaningful difference." Replace windows in a house that's losing heat through the attic and walls, and you're pouring water into a leaky bucket. SEAI wants you to fix the bucket first, which is fair enough, and those insulation upgrades come with their own grants.
How to check your HLI
There are three ways to find out if your home meets the 2.3 threshold:
1. Check your BER Advisory Report
If you already have a BER certificate, it comes with an Advisory Report. Look at the insulation sections. If your attic and wall insulation are rated "Good" or "Very Good", you almost certainly meet the HLI requirement. You can look up your existing BER at ndber.seai.ie using your MPRN (from your electricity bill).
2. Already had SEAI insulation grants?
If your home previously received an SEAI grant for attic or wall insulation, you're very likely already below 2.3. SEAI has confirmed that homes with prior insulation grants are generally good to go.
3. Get a BER assessment
If you're unsure, this is the definitive way to find out. A BER assessor calculates your exact HLI as part of the assessment. You'll get a certificate with your rating plus an Advisory Report that tells you exactly what insulation you need (if any) to get below 2.3. It typically costs €200–€350 and pays for itself many times over in avoided mistakes and unlocked grants. If you're in Dublin or the surrounding counties, Homerating.ie can usually get an assessor to you within a few days.
Homes built after 2005 usually meet the HLI requirement already. Homes built 1990–2005 often meet it if they have reasonable insulation. Homes built before 1990 will typically need insulation upgrades first, but those upgrades come with their own SEAI grants.
Grant amounts by home type
| Home Type | Windows Grant | Doors Grant | Maximum Total |
|---|---|---|---|
| Detached house | €4,000 | €1,600 | €5,600 |
| Semi-D / End-terrace | €3,000 | €1,600 | €4,600 |
| Mid-terrace | €1,800 | €1,600 | €3,400 |
| Apartment | €1,500 | €1,600 | €3,100 |
The doors grant is €800 per external door, maximum 2 doors (€1,600 total). You can apply for windows, doors, or both at the same time.
What if your HLI is too high?
If your home doesn't meet the 2.3 HLI threshold, you need to insulate first. The good news: insulation comes with its own grants, and the combination of insulating then replacing windows gives you much better results than windows alone.
The most common path:
- Apply for attic insulation grant (up to €2,000 for a detached home). get that done first
- Apply for cavity wall insulation grant (up to €1,800 for a detached home). if your home has cavity walls
- Get a post-works BER confirming your HLI is now 2.3 or below
- Apply for the windows and doors grant. you now qualify
You claim separate grants for each step. A detached home doing all three could receive up to €2,000 + €1,800 + €5,600 = €9,400 in total grants.
The smartest first move is to get a BER assessment, your assessor can tell you immediately whether your HLI is already below 2.3 or what specific insulation you need to get there. It avoids the situation where you apply for the windows grant and get rejected because of an insulation gap you didn't know about. Get a BER assessment from Homerating.ie →
You must have SEAI grant approval before work begins for each individual grant. Read our full guide on this rule →
Other eligibility requirements
Beyond the HLI, you also need to meet these requirements for the windows and doors grant:
- Home must be built and occupied before 2011
- Must have a valid MPRN (Meter Point Reference Number)
- New windows must achieve a U-value of 1.4 W/m²K or better (most modern double and triple-glazed units meet this)
- Installation must be by an SEAI-registered contractor
- You must get grant approval before work begins
- A post-works BER is required after installation
Check all the grants your home qualifies for
Our calculator covers windows, insulation, heat pumps, solar, and every other SEAI grant.
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