A BER (Building Energy Rating) tells you how energy efficient your home is. It’s displayed as a colour-coded label from A1 (most efficient) down to G (least efficient), similar to the energy labels on appliances.
The BER scale
| Rating | kWh/m²/year | Typical description |
|---|---|---|
| A1 | < 25 | Near passive house standard |
| A2 | 25–50 | Highly insulated new builds |
| A3 | 50–75 | Modern high-performance |
| B1 | 75–100 | Good modern standard |
| B2 | 100–125 | Decent modern insulation |
| B3 | 125–150 | Adequate, minimum for heat pump |
| C1 | 150–175 | Average 1990s–2000s home |
| C2 | 175–200 | Modest insulation |
| C3 | 200–225 | Older home, partial upgrades |
| D1 | 225–275 | Poor, common in 1970s–80s homes |
| D2 | 275–325 | Very poor |
| E | 325–400 | Energy inefficient |
| F | 400–450 | Major works required |
| G | > 450 | Very old poorly insulated home |
Typical BER by era in Ireland
| Era | Typical BER | Notes |
|---|---|---|
| Post-2021 (new builds) | A2–A3 | Mandatory nZEB standard |
| 2006–2021 | B2–C1 | Improved Part L standards |
| 1993–2005 | C1–D1 | Basic cavity walls, some insulation |
| 1970s–1992 | D1–E | Oil heating, poor insulation |
| Pre-1970s | E–G | Solid walls, single glazing common |
How BER affects your home’s value
Research consistently shows homes with higher BER ratings sell for more and faster. A C-rated home typically commands a premium over a D or E-rated equivalent. An A or B-rated home can attract a premium of 3–8% in some markets.
BER also affects mortgage costs. Some lenders offer preferential “green mortgage” rates for homes with BER B3 or better.
Typical BER improvements from upgrades
| Upgrade | Typical BER improvement |
|---|---|
| Attic insulation (100mm → 300mm) | 1–2 rating bands |
| Cavity wall insulation | 1–2 rating bands |
| External wall insulation | 2–3 rating bands |
| Oil boiler → air-to-water heat pump | 2–4 rating bands |
| Solar PV (3–4 kWp) | 1–2 rating bands |
| All of the above | Often C or D → A2/A3 |
How to get a BER assessment
A BER assessment must be carried out by a SEAI-registered BER assessor. The assessment takes about 1–2 hours and involves measuring the home’s fabric, heating systems, and windows.
Grant for BER assessment: €50 (individual scheme).
Find a BER assessor at seai.ie/ber.
Source: SEAI, 12 June 2026