The €12,500 SEAI Heat Pump Grant is the cornerstone of Ireland's National Retrofit Plan. However, heat pumps operate at lower, high-efficiency water temperatures (35°C to 45°C) compared to traditional oil or gas burners (75°C). To ensure your radiators heat your home comfortably on sub-zero winter mornings, your home must pass the Heat Loss Indicator (HLI) check.
What is the Heat Loss Indicator (HLI)?
The HLI calculation (expressed in W/K/m²) quantifies how many watts of heat escape from your home for every degree difference between indoors and outdoors, divided by total floor area.
- HLI ≤ 2.0 W/K/m²: Automatic Pass. Eligible for direct heat pump grant approval.
- 2.0 < HLI ≤ 2.3 W/K/m²: Technical Assessment required by certified BER assessor.
- HLI > 2.3 W/K/m²: Fail. Fabric insulation measures (attic / wall wrap) must be completed first.
How to Reduce Your HLI Score Fast
If your home currently scores between 2.4 and 3.2 W/K/m², you do not need a complete whole-house rebuild. Typically, two targeted measures bring 90% of Irish homes under the 2.0 limit:
- Attic Top-Up to 300mm: Reduces roof U-value from 0.44 to 0.13 W/m²K (€2,500 grant).
- Cavity Wall Pumping or External Wrap: Reduces wall transmission by up to 70% (€8,000 grant).
Check Your Heat Pump Suitability Today
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