Last updated: August 2026
An air to air heat pump is the heat pump most Irish people have already met without knowing it - it is, in effect, the indoor/outdoor split unit you see in shops and hotels, heating (and cooling) the air directly instead of heating water for radiators. They are dramatically cheaper to install than the air-to-water systems Ireland's grants favour - roughly €1,500-€3,500 for a single room unit versus €8,500+ for a whole-house system - and for the right home they are a genuinely clever purchase. For the wrong home they are a partial answer sold as a full one. This guide explains the difference honestly.
⚡ Quick Summary
🌿 What it is: a heat pump that warms air and blows it into the room - no radiators, no hot water cylinder, no pipework.
🌿 Cost: roughly €1,500-€3,500 per indoor unit installed; multi-room systems ~€4,000-€8,000. A fraction of air-to-water money.
🌿 Efficiency: excellent - typically 3-4 units of heat per unit of electricity, like all good heat pumps.
🌿 Bonus nobody mentions: it also cools - increasingly relevant in Irish summers.
🌿 The catch: it does not heat your water - the immersion or boiler still does that job.
🌿 Grants: air-to-air attracts a much smaller SEAI grant (€3,500 under the current scheme - confirm on seai.ie) versus up to €12,500 for air-to-water.
🔄 Air-to-Air vs Air-to-Water: The Real Difference
🌿 Air-to-water (73% of Irish installs) replaces your boiler entirely: it heats water for radiators or underfloor heating and your taps, serves the whole house, and unlocks the full €12,500 grant package. Costs and suitability are covered in our air-to-water cost guide.
🌿 Air-to-air heats the air in the rooms it serves, fast. No cylinder, no radiator compatibility questions, install measured in hours not days. But hot water stays with your existing system, and whole-house coverage needs multiple indoor units.
🌿 The efficiency story is the same: both move heat rather than generate it, so both deliver 3-4x the heat per euro of electricity that a plug-in electric heater manages - the technology in our heat pump guide applies to both.
🎯 Where Air-to-Air Genuinely Shines
🌿 The extension or garden room the central heating never reached - one unit solves it without touching the plumbing.
🌿 Apartments where an outdoor air-to-water unit and cylinder are impossible, but a compact split system fits.
🌿 The all-day room: heating the living room brilliantly while the boiler handles the rest can cut total bills in homes that only really occupy two rooms.
🌿 Replacing electric storage or panel heaters: against storage heaters or plug-in rads, an air-to-air unit does the same job for a third of the running cost.
🌿 Summer cooling: the same unit reverses - and after recent Irish summers, that is no longer a novelty feature.
🚫 Where It Falls Short
🌿 Hot water: your immersion or boiler keeps that job, with all its running costs.
🌿 Whole-house heating in a leaky home: blowing warm air into an uninsulated house is expensive whatever makes the warm air - fabric first still applies.
🌿 The BER and grant maths: air-to-water transforms your BER and captures the big grant; air-to-air improves comfort but moves the official needle less.
🌿 Aesthetics and noise: a wall unit indoors and a fan unit outdoors - quiet, but not silent, and visible.
⚠️ Common Mistakes to Avoid
🌿 Buying it as a full heating system for a draughty house: it is a room solution or a well-insulated-home solution - not central heating in a box.
🌿 Comparing its price to air-to-water and calling it a bargain: they do different jobs; compare like with like.
🌿 Skipping the grant check: scheme details move - confirm the current air-to-air position on seai.ie before assuming either way.
🌿 Cheap unbranded units: the compressor is the product; established brands with Irish service networks earn their premium.
🌿 Forgetting who installs it: refrigerant work needs an F-gas certified installer - ask.
❓ Frequently Asked Questions
🔹 What is an air to air heat pump?
A heat pump that heats indoor air directly through wall-mounted units, rather than heating water for radiators. It is the same technology as air conditioning, running in reverse.
🔹 How much does an air to air heat pump cost in Ireland?
Indicatively €1,500-€3,500 for one room unit installed, and €4,000-€8,000 for multi-room systems - versus €8,500-€18,000 before grants for whole-house air-to-water.
🔹 Is there an SEAI grant for air to air heat pumps?
A smaller grant than air-to-water - €3,500 under the current scheme versus up to €12,500. Confirm the current figure on seai.ie before deciding between systems.
🔹 Are air to air heat pumps cheap to run?
Yes - delivering 3-4 units of heat per unit of electricity, they cost roughly a third of equivalent electric heaters to run, and compete well with gas for room heating.
🔹 Do air to air heat pumps work in Irish winters?
Modern units heat effectively well below freezing - Irish winters are comfortably within their range, with efficiency dipping only on the coldest days.
🔹 Can it cool my house in summer?
Yes - the same unit reverses to provide cooling and dehumidification, which no radiator-based system can offer.
📚 Related Guides
🌿 Heat Pumps
🌿 Air-to-Water Heat Pump Cost
🌿 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 set by the SEAI and correct as of August 2026 - always confirm current terms at seai.ie. This site is not affiliated with SEAI.