Last updated: September 2026
A new gas boiler, supplied and fitted, costs most Irish households €2,200-€4,000 in 2026; a new oil boiler €2,800-€5,000. Bord Gáis Energy's headline offer is from €2,999 for a Worcester Bosch with a 10-year warranty, independent installers quote like-for-like gas swaps from about €2,200, and the extras - a powerflush, a moved flue, a combi conversion, a new oil tank - are what push a job past €4,500. This guide sets out what each type of replacement costs, what changes the price, what the rules require, the one grant that does exist, and when the answer is not a boiler at all.
⚡ Quick Summary
🌿 Gas, like-for-like: €2,200-3,300 installed. Combi €2,500-4,500. System boiler (with cylinder) €2,600-4,900. A 4+ bathroom home with a 30 kW+ boiler sits at the top of each range.
🌿 Oil, like-for-like: €2,500-4,500 installed; oil combi or full system €3,300-5,500. Grant Vortex and Firebird Envirogreen units are €1,300-2,100 before fitting; labour €1,100-2,200 by region.
🌿 Common extras: powerflush €250-400 · flue moved or extended €350-1,200 · relocating the boiler €500-1,500 · regular-to-combi conversion €600-1,200 · magnetic filter €260-390 · smart controls €200-350 · new oil tank from €950.
🌿 No SEAI grant for the boiler. The €700 heating controls grant is the only support, and the Warmer Homes Scheme no longer fits fossil-fuel boilers at all.
🌿 Rules: gas work must be done by a Registered Gas Installer (it is the law); any replacement boiler must be condensing, at least 90% efficient, with proper controls (Part L).
🌿 The saving: from a 15-year-old ~70% boiler to a ~92% condensing one cuts fuel use by 15-25% - €225-375 a year on gas, €360-600 on oil at 2026 prices.
🔥 Gas Boiler Replacement Cost (2026)
Published Irish installer price guides from spring and summer 2026 land in a tight band:
🌿 Like-for-like swap: €2,200-3,200 (independent installers); Bord Gáis Energy from €2,999 (€2,749 with its current €250 discount) for a Worcester Bosch Greenstar 4700i system boiler, 10-year warranty and a free first-year service.
🌿 By brand, supplied and fitted (24-30 kW): Ideal Logic €2,790-2,890 (5-yr warranty); Worcester Bosch €2,890-3,090 (10-yr); Viessmann €3,190-3,210; Baxi and Vaillant €2,000-3,500 depending on model and installer.
🌿 By home size: 1-2 bed (15-18 kW) about €2,500; 3 bed (24 kW) about €2,800; 4-5 bed (30 kW) about €3,000, before extras.
🌿 Combi conversion (removing the cylinder and tanks): packages of €3,995-4,495, or add €600-1,200 to a like-for-like price.
🌿 Budget installers advertise "from €1,699" with a 5-year warranty; check what boiler, what flue work and what controls are inside that number.
🛢️ Oil Boiler Replacement Cost (2026)
🌿 Straightforward swap: €2,000-3,500 (Dublin installers); €3,000-4,500 supply-and-fit is the more typical national range.
🌿 Full condensing install with upgrades: €3,000-6,000.
🌿 The unit: Grant Vortex Utility or External 15-26 kW about €1,830-1,860 trade, 26-36 kW €2,010-2,140; Firebird Envirogreen €1,330-1,550. Grant gives a 10-year guarantee when a Grant-accredited installer fits it with a Mag One filter; Firebird 5 years.
🌿 Labour: €1,100-2,200 - Dublin and Leinster €1,250-1,800; Cork and Munster €1,150-1,700; Galway and the west €1,100-1,650; a complicated retrofit €1,850-2,000+.
🌿 The tank: a new bunded plastic tank of 900-1,200 L runs from about €950 fitted. Insurers increasingly insist on a bunded tank.
🌿 HVO-ready: converting a modern oil boiler to run on HVO costs €300-500 on top; some new units come ready.
🔹 Estimate your own replacement
Indicative ranges only, drawn from published Irish installer price guides and offers (spring-summer 2026, VAT included). Real quotes vary with brand, warranty length, access and region - Dublin labour runs €100-300 above the west and midlands. There is no SEAI grant for the boiler itself; the €700 heating controls grant applies only to eligible controls fitted by an SEAI-registered contractor, and is shown separately. Always get three written quotes from a Registered Gas Installer (gas) or OFTEC-registered technician (oil).
🧰 What Pushes the Price Up
🌿 Powerflush (€250-400): most manufacturers require the system to be flushed before a new boiler goes on, or the warranty is void. Not optional on a 15-year-old system.
🌿 Flue changes (€350-1,200): modern condensing boilers need a flue that meets current clearance rules; an old flue position often does not.
🌿 Moving the boiler (€500-1,500): from a bedroom press to the utility room, say. New pipe runs, new flue, a condensate drain.
🌿 Controls (€200-350 for a smart thermostat, €25-180 per TRV): Part L requires zone and time control on a replacement; a full heating-controls package is what the €700 grant covers.
🌿 Magnetic filter (€260-390) and inhibitor (€50-100): protects the new heat exchanger; often required for the longer warranty.
🌿 Access: scaffolding €200-400; asbestos board removal €300-800 in older houses.
🌿 Converting from oil to gas: a new gas connection is about €250 from Gas Networks Ireland where the main passes the house, plus the gas boiler and pipework.
📋 The Rules You Cannot Skip
🌿 Gas is regulated: since 2009 it has been a criminal offence for anyone other than a Registered Gas Installer to carry out domestic gas work. The installer must issue a Declaration of Conformance on completion; keep it - insurers and buyers ask for it.
🌿 Oil is not, in the same way. OFTEC registration is voluntary in the Republic; use an OFTEC-registered technician anyway and ask for the commissioning certificate.
🌿 Part L of the Building Regulations: a replacement oil or gas boiler must be a condensing model with a seasonal efficiency of at least 90%, with time and temperature controls. Non-condensing boilers are effectively no longer sold.
🌿 New builds have been steered off oil since the 2019 Part L / NZEB rules; there is no ban on replacing an oil or gas boiler in an existing home as of September 2026. The SEAI has called for a date after which no new fossil-fuel boilers could be installed, and no date has been set.
💶 Grants, Loans and the Heat Pump Question
There is no grant for a like-for-like boiler; our boiler replacement grant guide explains why and what exists around it. In short:
🌿 €700 heating controls grant (SEAI): home built and occupied before 2011, SEAI-registered contractor, post-works BER. Fit the controls with the new boiler and claim once.
🌿 Warmer Homes Scheme: free upgrades for households on qualifying payments - but since January 2025 it installs heat pumps, not boilers.
🌿 Heat pump grant, up to €12,500: the alternative to a €3,500 oil boiler in a reasonably insulated home. SEAI's 2025 median heat pump job was €15,000-16,800, so net cost after grant is €2,500-4,300 - within reach of a good oil boiler install, with far lower running costs on a heat pump tariff.
🌿 Finance: the Home Energy Upgrade Loan only covers SEAI-grant-aided works, so it applies to a heat pump, not a boiler. Bord Gáis and some installers offer finance on boilers; compare the APR with a credit union loan.
📉 Is It Worth Replacing a Working Boiler?
A boiler lasts 10-15 years (gas) or 12-20 (oil). Efficiency drops with age: an older non-condensing boiler runs at 65-75%, a new condensing unit at 90-95%. That gap is worth roughly 15-25% of the fuel bill: €225-375 a year on a €1,500 gas bill, €360-600 on a €2,400 oil bill at 2026 oil prices. Against a €3,000 install that is an 8-12 year payback on fuel alone - so replace when repairs start, when parts become unavailable, when it fails a service, or when you are re-doing the heating anyway. Until then, an annual boiler service at €80-150 is the better spend.
⚠️ Common Mistakes to Avoid
🌿 Taking one quote: three written quotes for the same spec routinely differ by €600-1,000.
🌿 Skipping the powerflush to save €300: sludge kills a new heat exchanger and voids the warranty.
🌿 Using an unregistered gas fitter: illegal, uninsurable and a carbon monoxide risk.
🌿 Buying too big: a 30 kW boiler in a 3-bed semi short-cycles and wastes fuel. Ask for a heat-loss calculation.
🌿 Replacing the oil boiler without pricing a heat pump: for a pre-2011 home with decent insulation, the grant closes most of the gap.
🌿 Forgetting the controls grant: €700 back on work you were doing anyway.
❓ Frequently Asked Questions
🔹 How much is a new gas boiler in Ireland?
About €2,200-3,300 fitted for a like-for-like swap, €2,500-4,900 for a combi or system boiler, before extras such as a powerflush or a moved flue.
🔹 How much is a new oil boiler in Ireland?
About €2,800-4,500 fitted for a straightforward replacement, €3,300-5,500 for a combi or full system, plus €950+ if the tank needs replacing.
🔹 Is there a grant for a new boiler?
No. The only SEAI support is €700 towards heating controls. The heat pump grant of up to €12,500 is the alternative route.
🔹 Are oil boilers being banned?
Not in existing homes as of September 2026. New builds have been steered off oil since 2019, and the SEAI wants a cut-off date for fossil-fuel boilers, but none has been set.
🔹 Combi or system boiler?
Combi for one bathroom and limited space (no cylinder, instant hot water, weaker flow to two showers at once). System boiler for two or more bathrooms, or if you want solar thermal or a future heat pump to feed a cylinder.
🔹 How long does the job take?
A like-for-like swap is usually one day; a combi conversion or a relocation two to three days.
📚 Related Guides
🌿 Heat Pumps
🌿 Air-to-Water Heat Pump Cost
🌿 Air-to-Air Heat Pumps
🌿 Heating Oil Prices
🌿 Heating Oil by County
🌿 HVO Fuel
🌿 Gas Boiler Service
🌿 Storage Heaters
🌿 Underfloor Heating
👉 All guides and calculators
Climate Jargon Buster is an independent resource. Prices are indicative ranges from published Irish installer guides and offers, correct as of September 2026 and including VAT; grant amounts are set by the SEAI, with which we are not affiliated - check seai.ie and get written quotes before committing.