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 (manual, 2026-06-12) (individual scheme).
For what the assessor actually does on the day, see BER assessments explained, and what a BER cert costs for current prices. If your rating is lower than you would like, how to improve your BER rating sets out which upgrades move the most bands, and the eligibility checker shows which of them attract a grant.
Find a BER assessor at seai.ie/ber.
Source: SEAI, source date 12 June 2026 (manually researched)