Boiler comparison: key differences between gas and oil boilers
Which boiler is best for your home in Ireland?
When choosing a new boiler, one of the key decisions is selecting the right fuel type. In Ireland, the most common options are natural gas and oil. Each has its own advantages, depending on factors like fuel availability, cost, efficiency, and environmental impact.
If your home is connected to the gas network, a gas boiler is often the best choice. However, for homes off the grid, an oil boiler may be necessary.
Read on to compare the pros and cons of each option.
Key differences between gas and oil boilers
Below we list some of the main differences between these two types of home heating systems.
FeatureFeature | Gas boilersGas boilers | Oil boilersOil boilers |
FeatureFuel supply | Gas boilersContinuous supply via the gas network | Oil boilersRequires storage tank and deliveries |
FeatureUpfront costs | Gas boilersLower installation costs | Oil boilersHigher installation costs due to storage tank |
FeatureRunning costs | Gas boilersGenerally lower | Oil boilersFuel prices fluctuate, may be more expensive |
FeatureEfficiency | Gas boilersUp to 98% with modern condensing models | Oil boilersSlightly lower efficiency than gas |
FeatureSpace requirements | Gas boilersCompact, no need for a storage tank | Oil boilersRequires space for an external tank |
FeatureMaintenance | Gas boilersLower, annual servicing recommended | Oil boilersMore maintenance needed (e.g. soot cleaning) |
FeatureEnvironmental impact | Gas boilersLower carbon emissions | Oil boilersHigher emissions, but biofuels can reduce impact |
FeatureLifespan | Gas boilers10–15 years | Oil boilers12–20 years |
Keeping your boiler running efficiently
Regular servicing keeps your boiler efficient, safe, and long-lasting. Avoid breakdowns and high energy bills with routine maintenance.
Read expert tipsComparing costs: gas vs oil
The cost of running a gas or oil boiler depends on fuel prices, efficiency, and usage. Below is a rough comparison based on current energy rates in Ireland.
Cost FactorCost Factor | Gas boilerGas boiler | Oil boilerOil boiler |
Cost FactorTypical installation cost | Gas boiler€2,999–€3,500* | Oil boiler€2,500–€4,500 |
Cost FactorAnnual fuel cost (average home) | Gas boiler€1,482** | Oil boiler€1,400–€1,900 |
Cost FactorAnnual servicing cost | Gas boiler€149–€199*** | Oil boiler€150–€200 |
Cost FactorPotential savings with a high-efficiency boiler | Gas boilerUp to 30% on fuel bills | Oil boilerUp to 25% on fuel bills |
While oil boilers may last slightly longer, the ongoing fuel and maintenance costs tend to be higher. Additionally, oil prices fluctuate more than gas, making budgeting less predictable.
*Bord Gáis Energy Local Heroes provide boiler replacement and installation starting from €2,999.
**The Estimated Annual Bill is calculated based on an average annual consumption of 11,000 kWh in gas (as defined by the CRU) and Bord Gáis Energy's standard gas price plan less any percentage discounts.
***Bord Gáis Energy provides boiler services starting from €149 for a once-off service.
Environmental impact
Gas boilers produce lower carbon emissions than oil boilers. Modern condensing gas boilers are also more efficient, reducing waste and energy consumption. Oil boilers, while improving with new burner technologies, still release more CO₂ per kWh of energy used.
However, there are ways to make oil heating more sustainable:
- Biofuels: Some modern oil boilers can run on biofuels (e.g. HVO), reducing carbon emissions.
- Efficiency upgrades: A-rated condensing oil boilers can improve energy efficiency.
If reducing your carbon footprint is a priority, gas is the cleaner choice.
Installation and space requirements
FactorFactor | Gas boilersGas boilers | Oil boilersOil boilers |
FactorInstallation complexity | Gas boilersEasier if connected to gas network | Oil boilersMore complex due to tank installation |
FactorSpace required | Gas boilersMinimal, as fuel is piped in | Oil boilersRequires outdoor space for storage tank |
FactorPlanning permission | Gas boilersNot required for standard installations | Oil boilersMay be needed for new oil tanks |
If you live in a rural area where gas isn’t available, an oil boiler may be your only option. However, it’s worth considering LPG (liquefied petroleum gas) as an alternative. LPG boilers function similarly to natural gas boilers but require a storage tank, similar to oil.
Which boiler should you choose?
Choose a gas boiler if:
✔️ Your home is connected to the gas network
✔️ You want a lower-maintenance and cleaner heating option
✔️ You prefer lower upfront and running costs
✔️ You have limited space and don’t want an external fuel tank
Choose an oil boiler if:
✔️ You live in a rural area not connected to the gas grid
✔️ You already have an oil storage system in place
✔️ You don’t mind managing fuel deliveries and storage
✔️ You’re considering biofuel options for lower emissions
Get a gas boiler quote today
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