Gas and heating

Gas boiler replacement

Taking out an old gas boiler and commissioning a new one in its place.

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Whether this needs a licence in Ireland

Ireland

Licence required

Registered Gas Installer (RGI)

Registered Gas Installer (RGI), issued or supervised by the Commission for Regulation of Utilities. Ask for the registration number before the work starts and check it on the public register. Check the register: www.rgi.ie

Wording approved by Talqero; not yet reviewed by a solicitor

Commission for Regulation of Utilitieswww.rgi.ieChecked 11/10/2026

Gas boiler replacement: what the job involves

Removing an old gas boiler and installing and commissioning a new condensing boiler, with its flue, condensate drain and controls, by a Registered Gas Installer. It is also the moment to decide whether a heat pump is the better replacement.

Also asked for as: new boiler · combi boiler installed · gas boiler fitter · condensing boiler · boiler swap

How the job is usually done

Survey the house, existing boiler, flue route, gas supply pipe size and hot water needs.
Agree the boiler type (combi, system or regular), its size, location and controls.
Drain the system, disconnect and remove the old boiler and any redundant tanks or cylinder.
Fit the new boiler, flue and condensate drain, upgrading gas pipework where it is undersized.
Clean the system, fit a magnetic filter and add inhibitor, then fill and bleed.
Commission the boiler, test gas tightness and combustion, set up controls and issue the Declaration of Conformance.

Gas boiler replacement: what is included

Usually included

Removing the old boiler
Fitting and commissioning the new boiler, flue and condensate pipe
System clean or flush, filter and inhibitor
Declaration of Conformance (Cert 2) and manufacturer registration

Usually not included — agree it separately

Moving the boiler to a new room, quoted separately
New radiators or a new hot water cylinder
Making good plaster and decorating where pipes were moved
Changes to the gas meter, which belong to Gas Networks Ireland

Materials and who supplies them

The boiler, flue kit, filter and controls, normally supplied by the installer
Copper pipe and fittings, supplied by the installer

How long it takes

A like-for-like swap usually takes one to two days; converting from a regular boiler to a combi or moving the boiler can take three or more.

When to book

Replace a failing boiler in summer if you can; in winter installers are busy and you may be without heat while waiting.

Gas boiler replacement: the rules in Ireland

What the official sources say, checked against them on the date shown. A summary, not legal advice — follow the link to read the rule itself.

Only a Registered Gas Installer may install, replace, alter, repair or service a gas appliance or gas pipework in a home, whether natural gas or LPG. Every RGI carries a photo ID card renewed each year, and can be checked on the register.
Applies to: the installer, and the homeowner who engages one
Energy (Miscellaneous Provisions) Act 2006; Register of Gas Installers of Ireland for the Commission for Regulation of Utilities · rgi.ie · Checked 9 October 2026
An RGI must issue a Declaration of Conformance (completion certificate) for all gas works and give the customer the original copy as soon as the work is finished. A service, safety check, repair or appliance fit is recorded on a Cert 3; a boiler replacement on a Cert 2.
Applies to: the installer
Energy (Miscellaneous Provisions) Act 2006; Register of Gas Installers of Ireland · rgi.ie · Checked 9 October 2026
An oil or gas boiler installed as a replacement in an existing home should reach a minimum seasonal efficiency of 90% where practicable, which in practice means a condensing boiler.
Applies to: the installer and the homeowner
Building Regulations Part L, Technical Guidance Document L (Dwellings) · gov.ie · Checked 9 October 2026
The Commission for Regulation of Utilities is the safety regulator for gas installers and supervises the RGI register.
Applies to: gas installers
Commission for Regulation of Utilities · cru.ie · Checked 9 October 2026

Grants

SEAI heating controls grant
A grant of €700 towards upgrading heating controls, with or without a new boiler. SEAI does not grant-aid fossil fuel boilers themselves.
Who qualifies: Homeowners, including private landlords, whose homes were built and occupied before 2011, using an SEAI registered contractor with approval before work starts. Not available where a heat pump grant has been or is being claimed.
seai.ie · Checked 9 October 2026
SEAI heat pump system grant, with boiler removal
Up to €14,500 for a house (€11,500 for an apartment): up to €10,500 for the heat pump, up to €2,000 for radiator or underfloor upgrades and €2,000 for removing an oil or gas boiler, storage heaters or a solid fuel system. SEAI announced the removal element on 29 September 2026, subject to final implementation arrangements.
Who qualifies: Homes built and occupied before 2021. Homes built before 2007 need a technical assessment first unless a valid BER shows a heat loss indicator of 2.3 W/K·m² or less. Approval must be in place before any work starts.
seai.ie · Checked 9 October 2026

What gas boiler replacement costs, and why

What jobs on Talqero came to

Not enough comparable jobs yet to publish a range here. Talqero shows a price range only once at least five comparable jobs, agreed prices or offers exist — a range from fewer would describe a handful of jobs, not the market. Post your job and compare the offers you get.

What affects the price

Like-for-like swap, or a change of type or location
Flue route and whether a new hole or a plume kit is needed
Gas pipe size between meter and boiler
Removing old tanks and the cylinder, and capping pipework
Boiler make, output and warranty length
VAT: work on a home is charged at the reduced 13.5% rate by a VAT-registered business, unless materials exceed two-thirds of the price; ask whether the quote includes it
VAT: building work on a home is charged at the reduced rate of 13.5% by a VAT-registered business — unless the materials come to more than two-thirds of the price, when Revenue’s two-thirds rule applies the goods rate to the whole job. Ask whether a quote includes VAT.

Paperwork to ask for at the end

Declaration of Conformance (Cert 2) for the boiler replacement
Manufacturer warranty registration and benchmark or commissioning record
Manuals for the boiler and controls

Safety

Condensate pipes running outside can freeze; ask for them to be sized and insulated properly.
Fit or test carbon monoxide alarms when the boiler is replaced.
The flue terminal must sit clear of windows, doors and boundaries; do not box it in afterwards.

Gas boiler replacement: before you hire

Questions to ask a tradesperson

May I see your RGI card, and will I get a Cert 2?
Is the system being cleaned and a filter fitted before the new boiler goes on?
What warranty comes with the boiler and what servicing does it require?
Would a heat pump work in this house with SEAI’s grant?
Is VAT included?

What you can do yourself

Not a DIY job in any part: gas work is reserved by law to Registered Gas Installers.

What to put in your task

What boiler do you have now?
What do you want to have afterwards?
How many bathrooms and showers are used at the same time?
Where is the boiler?
Have you considered a heat pump instead?

Photos that help

The current boiler with its label and the pipes underneath
The flue outside and the wall around it
The hot press and cylinder if there is one
The gas meter

Gas boiler replacement by county

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Questions about gas boiler replacement

Does gas boiler replacement need a licence in Ireland?

Yes. Registered Gas Installer (RGI), supervised by the Commission for Regulation of Utilities. Source: www.rgi.ie. Ask for the registration number and check it on the public register. Wording approved by Talqero; not yet reviewed by a solicitor.

Is there a grant for a new gas boiler?

No. SEAI does not grant-aid gas or oil boilers. Its heating controls grant can apply alongside a boiler change, and its heat pump grant includes support for removing an old boiler.

Combi or system boiler?

A combi heats water on demand and suits homes with one bathroom used at a time. Homes with several showers in use together usually do better with a system boiler and cylinder.

Can my new boiler go in the same place?

Usually yes, if the flue can meet the clearance rules. Moving it costs more because gas, water and condensate pipes all move.

Often booked with gas boiler replacement

Heating engineers