Heating oil vs gas in Ireland: which costs less?
Which is cheaper depends on your oil quote, your gas tariff and your heating system, so an annual bill for an “average house” won't settle it. Compare the cost of heating the same home, then add standing charges and the cost of switching.
Updated
Compare the cost of useful heat
Oil is sold by the litre and gas by the kilowatt-hour (kWh), and boiler losses change how much of either becomes heat in your home.
SEAI's domestic fuel comparison puts heating fuels on a common cost per useful kWh. It is a reference comparison, not a quote for your home, and it rests on the table's date and efficiency assumptions.
For your own comparison, collect these for each fuel:
| Heating oil | Natural gas |
|---|---|
| Delivered total and litres for your address | Unit rate and any standing charge |
| Expected annual consumption | Expected consumption for the same heating demand |
| Oil boiler efficiency and servicing | Gas boiler efficiency and servicing |
| Any tank or boiler work needed | Connection, installation and oil-system removal costs |
If an installer promises a saving, ask for the consumption and efficiency figures behind it.
Check whether your address can get mains gas
Use the Gas Networks Ireland address checker before paying for a changeover survey. A gas main on your road does not by itself confirm a connection or its price.
Gas Networks Ireland runs the network but does not sell you gas; you choose a retailer to supply and bill you. The CRU explains the distinction and connection process.
A cheaper running cost may not repay the changeover
Get an itemised quote for the connection, boiler, internal work and removal of the old oil equipment, and set it against the annual saving after standing charges and maintenance.
A €4,000 changeover that saves €200 a year has a simple payback of 20 years. Those are example numbers, not current prices or a forecast, and future fuel prices and repair costs can change the result.
If the existing boiler needs replacing anyway, count only the extra cost of switching over the replacement you would otherwise buy.
Keeping oil for now
When a replacement is due, assess other suitable systems as well as oil and gas. SEAI's home energy grants page lists current support; a grant alone does not tell you the running cost.