1. Compare annual energy on the same mileage
Open the Irish EV cost calculator. Enter the EV's kWh/100 km, the petrol or diesel car's L/100 km, and the percentage of charging you expect at home by night, at home by day and in public. The percentages must total 100%.
The defaults were verified on 31 July 2026: AA Ireland listed petrol at €1.75/L and diesel at €1.73/L; ESB's plan effective 1 July lists PAYG AC at €0.60/kWh and DC at €0.72/kWh. Replace every default that does not match your bill or normal network.
2. Build a purchase-cost row
Use the final on-road cash price for the exact trim, including delivery, paint, dealer charges and confirmed grant treatment. For finance, compare deposit, term, APR, monthly payments, final payment and total cost of credit—not the monthly payment alone.
SEAI states a maximum €3,500 grant for a qualifying new private M1 BEV. From 1 August 2026 the qualifying price ceiling is €50,000. Revenue states that qualifying BEVs can receive up to €5,000 VRT relief through 31 December 2026, with relief tapered above an OMSP of €40,000 and unavailable above €50,000.
3. Add buyer-specific costs
| Cost | Evidence to use |
|---|---|
| Insurance | Written like-for-like quotes for the named drivers and addresses |
| Home charging | Site-specific installed quotation and confirmed SEAI eligibility |
| Servicing and tyres | Manufacturer schedule plus local quotations for the exact wheel/tyre size |
| Finance | Total cost of credit and final payment |
| Resale | A conservative range, stress-tested rather than treated as certain |
4. Stress-test the decision
- Public-only charging: set home shares to zero and public to 100%. Consider charger availability and dwell time as well as price.
- Low mileage: lower annual kilometres; fixed purchase and finance differences then matter more.
- Winter motorway use: enter a higher EV consumption figure rather than relying only on WLTP.
- Used vehicles: compare battery-health evidence, remaining warranty, service history and tyre condition.
Decision rule
An EV can have a clear energy-cost advantage for a buyer with regular home charging, but that does not automatically make it the cheaper car overall. A public-charging buyer may still prefer an EV for other reasons, while an efficient existing diesel may be cheaper to keep than replacing it immediately. The correct answer is the one that survives your written-price, insurance, charging and resale stress tests.