Last updated: August 2026
An air to water heat pump costs most Irish homes €8,500-€18,000 installed – before SEAI support of up to €12,500 brings the net cost down as far as €4,000-€8,000 for eligible homes. It is the heat pump type Ireland has standardised on: it replaces your boiler directly, heats your radiators and hot water tank, and runs on electricity at 300-400% efficiency. This guide breaks the cost down properly – unit, installation, the “hidden” extras like radiator upgrades – along with running costs versus oil and gas, and the grant stack that changes the maths.
⚡ Quick Summary
🌿 Installed cost: typically €8,500-€18,000 for an air-to-water system in an average home, before grants.
🌿 The grant stack: €6,500 for the heat pump + up to €2,000 for heating-system upgrades + €4,000 Renewable Heat Bonus if switching from fossil heating = up to €12,500.
🌿 Net cost: many eligible homes land at €4,000-€8,000 after support.
🌿 Running costs: 300-400% efficiency means each kWh of electricity delivers 3-4 kWh of heat – typically beating oil and gas bills on the right tariff.
🌿 The catch: your home needs reasonable insulation first (a heat-loss assessment is required), and radiator or cylinder upgrades can add cost.
🌿 Air-to-air is different: €3,500 grant, no hot water, cheaper install – a different product for different needs.
💶 The Cost Breakdown, Line by Line
🌿 The heat pump unit: €4,000-€8,000 depending on size (8-16 kW typical) and brand.
🌿 Installation and commissioning: €2,500-€5,000 – outdoor unit siting, plumbing, controls and electrics.
🌿 Hot water cylinder: €1,000-€2,000 – most installs need a new high-efficiency cylinder.
🌿 Radiator/emitter upgrades: €0-€3,000 – heat pumps run at lower temperatures, so some homes need larger radiators (the €2,000 heating-system grant exists precisely for this).
🌿 Electrical works: €300-€800 where the fuse board needs attention.
Well-insulated newer homes cluster at the bottom of the range; older homes needing radiator surgery push toward the top. Get itemised quotes from SEAI-registered installers – the same vetting rules apply.
💰 The Grant Stack Explained
The SEAI’s maximum €12,500 is three separate pieces:
🌿 €6,500 for the air-to-water heat pump itself (€3,500 for air-to-air).
🌿 Up to €2,000 for central heating upgrades – radiators, pipework or underfloor heating where the survey requires them.
🌿 €4,000 Renewable Heat Bonus for switching from oil, gas, solid fuel or electric storage heating.
Conditions: home built before 2021, a heat-loss assessment showing the home is heat-pump-ready (insulation may need doing first – the attic and wall grants stack alongside), an SEAI-registered installer, and grant approval before work starts. The full landscape is in our SEAI grants guide.
🔥 Running Costs: Heat Pump vs Oil vs Gas
The efficiency arithmetic is the whole story: a heat pump turns 1 kWh of electricity into 3-4 kWh of heat, so even at ~33c/kWh electricity, delivered heat costs roughly 8-11c per kWh – and less on a smart tariff with the pump scheduled cleverly. Oil at today’s ~€1.37/litre works out around 13-14c per kWh of heat in a typical boiler; gas sits between. For a typical home that means €300-€700 a year saved versus oil, more against electric or solid-fuel heating – and the gap widens every year the carbon tax rises. Pair it with solar panels and summer hot water becomes close to free.
🌬️ Air-to-Water vs Air-to-Air: Don’t Mix Them Up
🌿 Air-to-water (this article): heats radiators/underfloor and your hot water tank – a full boiler replacement. €6,500 grant.
🌿 Air-to-air: blows warm (or cool) air through indoor units – no hot water, no radiators. Cheaper (€3,000-€8,000 installed), €3,500 grant, great for well-insulated smaller homes and extensions, but you keep another system for hot water.
Our full heat pump guide compares all types, including ground-source.
⚠️ Common Mistakes to Avoid
🌿 Skipping insulation first: a heat pump in a leaky house runs constantly and expensively – fabric first is the rule, and the heat-loss assessment enforces it.
🌿 Comparing quotes without the radiator line: one quote including emitter upgrades will look dearer than one that conveniently omits them – compare complete scopes.
🌿 Starting work before grant approval: work done before the SEAI letter is ineligible – the sequencing rule catches people every year.
🌿 Oversizing the pump: bigger is not better – an oversized pump short-cycles and wears; insist on sizing from the heat-loss calculation.
🌿 Judging running costs on a standard tariff: the economics improve meaningfully on smart/night tariffs with scheduled operation.
❓ Frequently Asked Questions
🔹 How much does an air to water heat pump cost in Ireland?
Typically €8,500-€18,000 installed before grants; with the full €12,500 SEAI stack, eligible homes commonly land at €4,000-€8,000 net.
🔹 What grants are available?
€6,500 for the pump, up to €2,000 for heating-system upgrades, and a €4,000 Renewable Heat Bonus for switching off fossil or storage heating – up to €12,500 combined.
🔹 Are air to water heat pumps worth it in Ireland?
For reasonably insulated homes, generally yes: lower running costs than oil or gas, no fuel deliveries, cooling-free summer hot water, and a large BER improvement that lifts property value.
🔹 Do heat pumps work in Irish winters?
Yes – modern units heat effectively at -15°C and below, far colder than Irish winters get. Efficiency dips on the coldest days but remains well above 100%.
🔹 Do I need new radiators for a heat pump?
Sometimes: heat pumps run at lower water temperatures, so undersized radiators may need upgrading – that is what the €2,000 heating-system grant covers. The heat-loss survey tells you exactly which ones.
🔹 How long does a heat pump last?
Typically 15-20+ years with annual servicing – comparable to or better than a boiler, with far fewer moving parts in the combustion sense: there is no combustion at all.
📚 Related Guides
🌿 Heat Pumps
🌿 Air-to-Air Heat Pumps
🌿 Heating Oil Prices
🌿 Heating Oil by County
🌿 HVO Fuel
🌿 Boiler Replacement Cost
🌿 Gas Boiler Service
🌿 Storage Heaters
🌿 Underfloor Heating
👉 All guides and calculators
Climate Jargon Buster is an independent resource providing plain-English information on climate, energy and sustainability topics for an Irish audience. Costs are indicative and vary by home and installer; grant amounts are correct as of August 2026 and are set by the SEAI. For official grant terms and to find a registered contractor, visit seai.ie. This site is not affiliated with SEAI – always check the official website for current figures.