For a heat pump to run efficiently, your home generally needs a BER of B3 or better — but the figure that really matters is the heat-loss indicator (HLI). SEAI looks for an HLI of around 2.0 W/K/m² or below. Get the fabric to that point and a heat pump will heat your home cheaply at low flow temperatures; skip it and the system will run hard and cost more.
Why the heat-loss indicator matters more than the band
A BER band is a useful headline, but heat pumps are sized and judged on heat loss. The heat-loss indicator measures how much heat your home loses relative to its floor area:
| Heat-loss indicator (W/K/m²) | Suitability for a heat pump |
|---|---|
| ≤ 2.0 | Well suited — efficient at low flow temperatures |
| 2.0–2.3 | Borderline — may need fabric upgrades first |
| > 2.3 | Poorly suited until insulation is improved |
A heat pump delivers heat at a lower temperature than an oil or gas boiler. In a leaky house that heat escapes faster than it’s supplied, forcing the pump to run hotter and less efficiently — wiping out the savings. A low HLI means the home holds heat, so the pump runs gently and cheaply.
Getting your home heat-pump ready
If your HLI is too high, fabric upgrades bring it down. Tackle them in order of impact:
| Upgrade | Effect on heat loss | SEAI grant |
|---|---|---|
| Attic insulation | Large reduction, low cost | Yes — insulation grant |
| Wall insulation (cavity/external) | Largest surface, big reduction | Yes — insulation grant |
| Airtightness & draught-proofing | Cuts uncontrolled heat loss | Often part of works |
| Windows upgrade | Reduces glazing losses | Yes — windows grant |
| Heating controls | Improves how heat is used | €700 |
See our roadmap in how to improve your BER, and the practical detail in attic insulation and insulation grants. Older properties have specific considerations — read heat pumps in older homes.
The heat pump technical assessment
Before committing, SEAI requires a heat pump technical assessment — a qualified assessor checks your home’s heat loss and confirms whether a heat pump will perform well, and what (if anything) needs upgrading first. There’s a grant toward it:
- Heat pump technical assessment grant: €200
This is the smartest first step. It tells you exactly where you stand on the HLI before you spend on the system itself. The heat pump unit grant of €6,500 follows once the home qualifies.
The typical path
Most homes that aren’t yet ready follow this sequence:
- Get a current BER to set your baseline — see BER ratings explained.
- Book the technical assessment to find your heat-loss indicator.
- Upgrade fabric (attic, walls, airtightness) to push HLI to 2.0 or below.
- Install the heat pump once the assessment confirms suitability.
Doing it in this order also means a smaller, cheaper heat pump, since a well-insulated home needs less heating capacity. For full pricing, see heat pump costs in Ireland.
Next step
Find out whether your home already qualifies — and which fabric grants apply if it doesn’t.
Check your eligibility at /grants/check-eligibility/.
Source: SEAI, 12 June 2026 Source: SEAI, 12 June 2026