Air to Water, Air to Air and Ground Source Heat Pumps Explained
How the main types of domestic heat pump actually differ from each other.
Read guideHeat Pumps in Ireland
An independent guide to heat pumps for homes in Ireland: what makes a home a strong candidate, why your Heat Loss Indicator matters more than your BER, radiators, positioning and noise, current grants, and what to check before requesting quotations.
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Grants and criteria explained in plain English
How it works
Your heat pump journey
Four steps to help you make an informed decision, in your own time.
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Understand suitability, costs, grants and installation.
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Review likely costs and available grants before requesting quotations.
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Heat Pumps
What this guide covers
Installing a heat pump is a bigger change to how a home is heated than swapping one boiler for another, and the questions worth answering before you request quotations are not the ones most general explainers cover. This guide focuses on practical decision making: whether your home is a likely candidate, why your Heat Loss Indicator matters more than your BER letter, what happens to your existing radiators, where an outdoor unit can realistically go, current grant support, indicative installation and running costs, and what to check before and during installation. This guide focuses on the air to water heat pump most homeowners in Ireland mean by the term. See our guide to air to water, air to air and ground source heat pumps if you want to confirm which type applies to your project first.
Suitability
What makes a home a strong or weak heat pump candidate?
Heat pumps suit some homes more easily than others, and a few practical factors will tell you a lot before you contact an installer.
- Fabric insulation. Well insulated walls and attic help a heat pump maintain comfortable temperatures at lower flow temperatures.
- Heat Loss Indicator. This figure, not your BER letter, actually determines grant eligibility and realistic suitability.
- Radiators. Radiators sized for a boiler may need upsizing. Underfloor heating suits a heat pump well.
- Outdoor space. Keep it clear of boundaries and bedroom windows.
- Indoor space. Room for a larger hot water cylinder and indoor equipment, typically in a hot press or utility room.
Suitability check
None of these factors rule a heat pump out on their own. A proper Heat Loss Indicator assessment, either from a valid BER or an SEAI registered Technical Advisor, is the only way to confirm suitability for your own home.
Heat loss
Why heat loss matters more than your BER rating
A Building Energy Rating is a useful general indicator, but it is not the figure that determines heat pump grant eligibility. That figure is your Heat Loss Indicator, a measure of how much heat your home loses for each degree of difference between inside and outside temperature.
Two homes with a similar BER can have different Heat Loss Indicators, depending on wall construction, window performance and how consistently insulation has been installed. Based on current SEAI guidance, the standard threshold for the Heat Pump System Grant is a Heat Loss Indicator of 2.0 W per K per square metre or lower. A home between 2.0 and 2.3 may still qualify where additional SEAI criteria are met. The figure is confirmed either by a valid BER or by a Technical Assessment carried out by an SEAI registered Technical Advisor. Homes built before 2007 usually need a Technical Assessment unless a valid BER already shows this figure directly. Homes built from 2007 onwards do not need one under the current process, though one can still be arranged.
Ask about your Heat Loss Indicator
A reputable installer or SEAI registered Technical Advisor will confirm your Heat Loss Indicator before you commit to a system size or a quotation. Treat any suitability claim made without this figure with caution.
How it works
Why heat pumps run differently from a boiler, and what that means for your radiators
A gas or oil boiler typically heats water to a high temperature in short bursts, then stops until the next call for heat. A heat pump generally works the other way: it runs for longer periods at a lower flow temperature, extracting heat from the outside air even in cold weather rather than burning fuel to generate it directly.
This difference matters for your radiators. Radiators sized for a boiler's higher flow temperature may not give out enough heat at the lower temperatures a heat pump typically runs at, particularly in larger rooms or poorly insulated parts of a home. Some rooms may need larger radiators, and underfloor heating, which already works at lower temperatures, tends to suit a heat pump particularly well.
This is exactly why a proper room by room heat loss calculation, not a general estimate, should be part of any heat pump quotation. This is covered further in Comparing quotations below, and in more depth in our guide to checking whether your radiators need upsizing.
Indoor equipment
Indoor space for cylinders and equipment
A heat pump system usually needs more indoor space than a combi boiler. A hot water cylinder stores the water the heat pump heats, since most heat pumps do not produce hot water instantly on demand the way a combi boiler does.
Alongside the cylinder, expect a buffer or expansion vessel, controls and, depending on the system, an indoor unit. A home without an existing hot water cylinder, or with a small hot press, may need to find new space for this equipment, commonly in a utility room, attic or garage.
Outdoor unit
Positioning your outdoor unit
The outdoor unit needs a clear, ventilated spot outside the home, close to where indoor pipework can connect through an external wall, and clear of boundaries, gates and airflow obstructions.
Domestic heat pumps are generally exempted development in Ireland, so planning permission is not usually required, subject to current planning conditions. Since 27 July 2026, the exemption is no longer limited to the rear of the house, though its other conditions still apply. Protected structures, conservation areas or any doubt should be checked with your local planning authority first.
Noise is part of the planning exemption itself. One of its conditions is that the unit's noise in normal operation must not exceed 43 dB(A), or 5 dB(A) above background noise if that is greater, measured at the nearest neighbouring inhabited dwelling. Site the unit away from your own and any neighbouring bedroom windows, and ask your installer for the manufacturer's published sound rating for the model quoted. See our guide to heat pump noise ratings for how to read and compare that figure between quotations.
Check with your local authority
Planning exemption conditions can change and can depend on your specific property. If you are in any doubt, confirm the current position with your local planning authority before installation.
Before you commit
When improving insulation first makes more sense
A heat pump is not always the first upgrade to make. Where a home has a Heat Loss Indicator well above the level needed to qualify for grant support, or where wall and attic insulation has never been upgraded, addressing the building's fabric first, or at the same time, often produces a better outcome than installing a heat pump onto a home that is still losing a lot of heat.
Talk to an assessor before deciding
An SEAI registered Technical Advisor or BER assessor can tell you whether insulation upgrades would meaningfully improve your Heat Loss Indicator before you commit to a heat pump quotation.
Grants
The Heat Pump System Grant
The main financial support for a home heat pump in Ireland is the SEAI Heat Pump System Grant. Based on currently published SEAI guidance:
- Since 6 October 2026, support is made up of three separately capped parts: up to €10,500 for the heat pump system, up to €2,000 towards central heating upgrade works such as radiators, pipework or underfloor heating, and a €2,000 Boiler Scrappage Grant, paid where an oil, gas or solid fuel system or electric storage heating is removed and replaced by the heat pump. The combined maximum is up to €14,500 for a house, and SEAI says eligibility for the central heating and boiler scrappage parts depends on your contractor's installation design. For an apartment, the qualifying maximum is up to €11,500. Where an existing heat pump is being replaced and the extra decarbonisation grants do not apply, support is up to €6,500 for a house and €4,500 for an apartment. A qualifying air to air heat pump can receive up to €9,500.
- Your home must have an MPRN and have been built and occupied before 2021. Eligibility is not limited to owner occupiers, and also extends to landlords, companies, charities, holiday homes and Approved Housing Bodies.
- For a home built before 2007, your Heat Loss Indicator generally needs to be 2.0 W per K per square metre or lower, or between 2.0 and 2.3 where additional SEAI criteria are met, confirmed by a valid BER or by an SEAI Technical Assessment. A home built from 2007 onwards does not need a Technical Assessment and can use SEAI's Self-Declaration form instead. A grant of €200 is available towards the cost of a Technical Assessment where one is carried out.
- The installation must be carried out by a contractor registered with SEAI for the type of work being carried out.
- A Building Energy Rating assessment completed after the works, by a registered BER assessor, is required before the grant is paid. A grant of €50 is available towards this assessment.
Check your own eligibility
Grant amounts, thresholds and conditions can change, and eligibility also depends on factors specific to your home and its history. Always confirm the current grant amount and your own eligibility directly with SEAI before assuming a grant applies to you.
The boiler scrappage grant is not a boiler grant
The €2,000 Boiler Scrappage Grant is only paid as part of an eligible heat pump installation that replaces your existing system. SEAI does not fund a new oil or gas boiler. If your heat pump application was already in progress when the grant was announced, SEAI has said eligible homeowners will receive the additional support. See our guide to new SEAI grants from October 2026 for the other changes that took effect on 6 October 2026.
Next steps
Want to see how this could work for your own home?
Work through the Heat Pump Readiness Check below to see how the practical factors on this page apply to your home, or if you already feel informed enough to take the next step, search for heat pump installers in Ireland now.
Costs
What does a heat pump cost to install in Ireland?
Every home is different, so the figures below are indicative planning ranges cross-checked across independent Irish cost research, not a quotation for your own project. The only way to know what your installation will actually cost is to get written quotations from more than one SEAI registered installer, based on your own home's Heat Loss Indicator and a room by room heat loss calculation.
Air to water heat pump
Typically in the region of €9,000 to €18,000, fully installed, before grant support. Most straightforward retrofits on an averagely sized home cluster towards the lower half of this range, with larger homes, bigger radiator changes or more complex sites pushing costs higher.
Ground source heat pump
Typically in the region of €15,000 to €30,000, fully installed, before grant support. The main driver is the ground works, horizontal trenching or a vertical borehole, which air to water systems do not need. See our guide to heat pump types for why this system suits fewer retrofits.
What a typical installation may include
Coverage varies between installers, but a typical quotation for an air to water system usually covers the outdoor unit, indoor controls and a buffer or expansion vessel, a hot water cylinder, standard pipework and wiring to connect the system, and commissioning and handover. Always confirm in writing exactly what your own quotation includes.
Possible additional costs
- Radiator changes. Upsizing or replacing radiators identified as too small once your room by room heat loss calculation is done.
- Hot water cylinder work. A larger cylinder, or new pipework and space adaptations, where your existing cylinder or hot press cannot accommodate the new system.
- Electrical work. A consumer unit or electrical supply upgrade, if your existing supply cannot support the heat pump's load.
- Difficult access. Longer pipe runs, scaffolding, or awkward access to the proposed outdoor unit position.
- Fabric upgrades. Attic or wall insulation needed to bring your Heat Loss Indicator down to a workable level, covered further in When improving insulation first makes more sense above.
Before and after grant support
The ranges above are before grant support. For an eligible home, current SEAI grant support can reduce the net cost by up to €14,500 for a house or €11,500 for an apartment, but the actual reduction depends on how your quotation splits cost between the heat pump itself, radiators and pipework, and whether an eligible existing heating system is being removed, since each part of the grant is capped separately. Ask your installer to show your quotation both before and after the grant amount they expect you to qualify for.
Why quotations vary
Two quotations for what looks like the same job can differ substantially. The main factors are your Heat Loss Indicator and the system size it points to, the specific brand and model quoted, how many radiators need to change, the hot water cylinder specified, any electrical work required, site access, and whether the price shown is before or after grant support and whether VAT is included. See What to check before and when comparing quotations below for a fuller checklist.
Planning information, not a quotation
The figures on this page are indicative ranges for planning purposes, drawn from independent Irish cost research. They are not a quotation, an estimate for your specific home, or a guarantee of what you will be charged. Only a written quotation from an SEAI registered installer, based on your own home, tells you what your installation will actually cost.
Running costs
Running costs and potential savings
What a heat pump costs to run, and whether it saves money against your current system, depends on your own home and how you use it. There is no single figure that applies to every household, and the following all make a genuine difference:
- Your home's heat demand. Insulation, glazing and your Heat Loss Indicator determine how much heat the system needs to supply in the first place.
- Seasonal system efficiency. The SCOP achieved in your home, covered further in COP, SCOP and flow temperature below.
- Required flow temperature. A system designed to run at a lower flow temperature generally runs more efficiently than one forced to run hotter.
- Electricity unit price and tariff. Standard, smart and night rate tariffs can produce meaningfully different running costs for the same system.
- Hot water demand. How much hot water your household uses, and at what temperature it is stored.
- Controls and weather compensation. Whether the system automatically adjusts its flow temperature to outdoor conditions, and how well it is set up.
- The system and fuel you are replacing. Oil, mains gas, electric storage heating and an older heat pump all give different starting points for comparison.
Be cautious of generic savings claims
You may see marketing claims that switching to a heat pump saves a fixed percentage, such as 40 percent, on heating costs. A figure like this depends entirely on the factors above, especially the fuel and system it is being compared against, so it may not apply to your own home. Ask an installer to base any savings comparison on your own Heat Loss Indicator, required flow temperature and current fuel costs, not a generic industry figure.
The clearest way to see how these factors apply to your own home is to work through the Heat Pump Readiness Check below, which asks about the practical factors that drive both suitability and running costs.
Upgrader.ie original tool
Heat Pump Readiness Check
Answer a few practical questions about your home to get a personalised summary of what to check before requesting quotations. This is an educational starting point only. It does not determine whether your home is suitable for a heat pump.
System types
Monobloc or split: which am I being quoted?
Most air to water heat pumps quoted in Ireland are built one of two ways. A monobloc system contains all its refrigerant components in a single outdoor unit, so only water pipes cross the wall into the home, which keeps the indoor installation relatively simple. A split system divides the components between an outdoor unit and an indoor unit connected by refrigerant pipework, which needs a qualified refrigerant handling installer but keeps the water circuit indoors. With a monobloc, the water pipes running out to the unit need to be insulated and protected against frost.
This is a genuine practical difference, but it is not usually a decision a homeowner needs to make unprompted. Your installer should recommend the type that suits your home and confirm clearly which one is being quoted. For the fuller picture of how air to water, air to air and ground source heat pumps differ, see our guide to heat pump types explained.
Reading the numbers
COP, SCOP and flow temperature
Heat pump quotations and marketing often quote efficiency figures. Knowing what they actually mean helps you compare quotations on a like for like basis.
COP, Coefficient of Performance, is measured under a single standardised laboratory condition, so it is a snapshot rather than a year round figure. SCOP, Seasonal Coefficient of Performance, averages performance across a full heating season under a range of standard conditions, and gives a more useful basis for comparing likely real world running costs between products.
Neither figure is a guarantee for your own home. Published COP and SCOP figures come from standardised testing, not your specific property, and actual performance also depends on your home's heat loss, how the system is sized and commissioned, and how you use its controls.
Design flow temperature, the temperature of the water leaving the heat pump for your radiators or underfloor heating, matters because a heat pump generally becomes less efficient the higher the flow temperature it needs to produce. This is exactly why the room by room heat loss calculation and radiator sizing covered above matter: a system designed and sized to run at a lower flow temperature will generally run more efficiently than the same system forced to run hotter because radiators are undersized.
What to ask installers to state in a quotation
Ask each installer to state the SCOP for the specific model quoted, not just a generic COP figure, the design flow temperature the system has been sized to run at for your home, and whether that flow temperature is based on your own room by room heat loss calculation rather than a general assumption.
Comparing quotations
What to check before and when comparing quotations
Two heat pump quotations that look similar on paper can involve very different levels of preparation. Before comparing prices, make sure you can answer the following for each quotation.
Heat Loss Indicator. Whether a Technical Assessment or your existing BER was used, and what figure it produced.
Room by room heat loss calculation. A calculation for each room, not a single whole house estimate.
System size and model. The specific make, model and rated output of the heat pump being quoted.
SCOP and flow temperature. The SCOP for the specific model, and the design flow temperature the system has been sized to run at for your home. See COP, SCOP and flow temperature above.
Radiator changes. Which radiators, if any, are being replaced or upsized, and which are staying as they are.
Hot water cylinder. The capacity and brand, and where it will be installed.
Outdoor unit position. The proposed location, and whether it was assessed against boundaries and windows.
Controls. What heating controls and thermostats are included, and whether they suit the system.
Electrical work. Whether any electrical upgrade is needed to supply the heat pump, and if it is included.
Contractor registration. That the installer is registered with SEAI for the type of work being carried out.
Warranties. What is covered, and for how long, on the heat pump, the cylinder and the installer's own workmanship.
Grant treatment. Whether the price shown is before or after grant support, and whether VAT is included.
BER. Whether arranging the required post works BER assessment is included in the price.
What is excluded. Ask directly what is not included, since this is where unexpected costs usually come from.
Commissioning and handover. What commissioning, system setup and homeowner instructions are included after installation.
No rankings or recommendations
Upgrader.ie does not rank, rate or recommend individual installers. This checklist is here to help you ask the right questions and compare answers, not to tell you which company to choose.
Installation
What happens during installation, and what to expect
Every project varies, but most home heat pump installations in Ireland follow a broadly similar sequence, and understanding it helps you judge how much disruption to expect.
1
Quotes and Technical Assessment
Get quotes from more than one SEAI registered installer, and arrange a Technical Assessment if your home needs one to confirm your Heat Loss Indicator.
2
Grant application
Once you have chosen an installer and a system, a grant application is made to SEAI and confirmed before work begins.
3
Installation day or days
The outdoor unit, indoor equipment and hot water cylinder are fitted, with any radiator changes carried out alongside. This typically takes longer than a boiler swap, and your heating and hot water may be off for periods during the work.
4
Electrical work and commissioning
The system is wired in, commissioned and set up, including controls and any smart heating features.
5
Post works BER
A Building Energy Rating assessment is completed after the works and published, which is required before your grant is paid.
6
Settling in
Heat pumps often need controls adjusted over the first few weeks as you learn how the system responds, particularly compared with how a boiler behaved.
FAQ
Frequently asked questions
Does my BER tell me if my home is ready for a heat pump?
Not on its own. Grant eligibility and a realistic picture of suitability depend on your Heat Loss Indicator, a specific measure of how much heat your home loses, rather than your BER letter alone. Two homes with a similar BER can have different Heat Loss Indicators. See Why heat loss matters more than your BER rating above.
Will I need to replace all my radiators?
Not necessarily. Heat pumps typically run at lower flow temperatures than a boiler, so some radiators sized for a boiler may need to be upsized, while others may already be adequate. A proper room by room heat loss calculation from your installer should confirm which, if any, need to change.
Do I need planning permission for a heat pump?
Domestic heat pumps are generally treated as exempted development in Ireland, subject to conditions in current planning regulations, so planning permission is not usually required. Protected structures, architectural conservation areas and any doubt about your own property should be checked with your local planning authority. See Positioning your outdoor unit above.
How much is the Heat Pump System Grant?
Since 6 October 2026, the Heat Pump System grant is made up of three separately capped parts: up to €10,500 for the heat pump system, up to €2,000 towards radiators, pipework or other central heating upgrade works, and a €2,000 Boiler Scrappage Grant where an oil, gas or solid fuel system or electric storage heating is removed. That gives a combined maximum of up to €14,500 for a house, but many homes will qualify for less. For an apartment, the qualifying maximum is up to €11,500. Always confirm the current amount and your own eligibility directly with SEAI.
How much does a heat pump cost to install in Ireland?
Based on independent Irish cost research, an air to water heat pump typically costs in the region of €9,000 to €18,000 fully installed before grant support, and a ground source system typically costs more, roughly €15,000 to €30,000, mainly due to ground works. These are indicative planning ranges, not quotations, and eligible homes can reduce the net cost with SEAI grant support. See What does a heat pump cost to install in Ireland above for what is usually included and what can add to the price.
Will a heat pump definitely reduce my heating costs?
Not by a fixed amount. Running costs and any savings depend on your home's heat demand, the system's seasonal efficiency, the flow temperature it needs to run at, your electricity tariff, your hot water demand, and the heating system and fuel you are replacing. A generic savings percentage quoted for another home will not necessarily apply to yours. See Running costs and potential savings above.
What is the difference between COP and SCOP?
COP, Coefficient of Performance, is measured under one standard laboratory condition, so it is a snapshot rather than a year round figure. SCOP, Seasonal Coefficient of Performance, averages performance across a full heating season and gives a more useful basis for comparing likely real world running costs between quotations. Neither figure guarantees what you will see on your own electricity bill, since actual performance also depends on your home and how the system is installed and set up. See COP, SCOP and flow temperature above.
Does Upgrader.ie install heat pumps?
No. Upgrader.ie is an independent information resource. We do not install heat pumps, and we do not currently have installer partnerships.
Latest data
What the latest figures suggest
900+
Heat pumps installed under SEAI home energy grant schemes in the first quarter of 2026, up 18 percent on the same period last year
Department of Climate, Energy and the Environment, 21 April 2026
Installation numbers are still small, but growing
Heat pump installations remain well behind solar PV in volume, but the year on year growth shows steady momentum. With grant support recently increased and a defined Heat Loss Indicator threshold now central to eligibility, the practical groundwork covered on this page, confirming your Heat Loss Indicator, understanding what happens to your radiators, and checking outdoor unit positioning, is becoming relevant to a wider group of homeowners in Ireland.
Related Guides
Related guides
Go deeper on some of the questions covered above.
How to Check Whether Radiators Need Upsizing for a Heat Pump
What a proper room by room radiator assessment involves, and what to ask an installer.
Read guide
Heat Pump Noise Ratings Explained
How to read a manufacturer's sound figure and compare noise between quotations.
Read guide
Sources
Sources and information date
Grants, eligibility and technical requirements are checked against official SEAI material. Indicative installation costs are cross-checked across independent Irish market sources, since no official published cost data exists for typical installation prices.
Official sources
Independent market sources for indicative costs
Information checked: 7 October 2026
Grant amounts, eligibility conditions and market pricing can change. This guide is reviewed periodically, but always confirm current grant amounts, your Heat Loss Indicator requirement and application steps directly with SEAI, and confirm actual costs with your own written installer quotations, before making a decision.
Next steps
Ready to check your own home?
Work through the Heat Pump Readiness Check for a sense of how suitable your home is, or if you already feel informed enough to take the next step, search for heat pump installers in Ireland and contact the ones that interest you directly.
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