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. Budget 2027 cut and froze the carbon tax on heating oil and gas, so that part of the gap will not grow for now. 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.