Heat Pump vs Gas Boiler — Which Is Right for Your Irish Home?

Running Costs: Heat Pump vs Gas Boiler

One of the biggest advantages of a heat pump is lower running costs. A well-installed air-to-water heat pump in an insulated Irish home typically costs €800–€1,200 per year to run, compared to €1,400–€2,000 per year for a gas boiler. That is a saving of €500–€800 annually.

The reason heat pumps are cheaper to run is efficiency. A modern gas boiler converts about 90% of the energy in gas into heat. A heat pump, by contrast, delivers 3–4 units of heat for every 1 unit of electricity it uses — this ratio is called the Coefficient of Performance (COP).

What Is COP and Why Does It Matter?

COP stands for Coefficient of Performance. It measures how efficiently a heat pump converts electricity into heat. A COP of 3.5 means the heat pump produces 3.5 kWh of heat for every 1 kWh of electricity consumed. In practice, most air-to-water heat pumps achieve a seasonal COP (known as SCOP) of 3.0–4.0 in Irish conditions.

Because electricity is more expensive per unit than gas, the heat pump needs this high efficiency to be cost-competitive. With a COP of 3.5, the effective cost per unit of heat from a heat pump is lower than from gas — and the gap widens as gas prices rise.

Upfront Costs

This is where gas boilers still have an advantage. A new gas boiler installation typically costs €2,500–€4,500. An air-to-water heat pump system, including the unit, hot water cylinder, and installation, costs €9,000–€16,000 depending on the size of your home and the complexity of the install.

However, SEAI grants significantly close this gap.

SEAI Grants for Heat Pumps

SEAI offers generous grants for heat pump installations:

• Air-to-water heat pump: €6,500 grant
• Ground-source heat pump: €6,500 grant
• Air-to-air heat pump: €3,500 grant

If you combine a heat pump with other upgrades under the One Stop Shop scheme (where you improve your BER by enough), grants can increase to as much as €12,500 for the heat pump element. This can bring the net cost of a heat pump system down to €3,000–€6,000 — much closer to the cost of a new gas boiler.

When Does a Heat Pump Make Sense?

A heat pump is an excellent choice if:

• Your home is well insulated (or you plan to insulate as part of the retrofit)
• You have underfloor heating or oversized radiators that work at lower flow temperatures
• Your existing boiler is old and due for replacement
• You want to future-proof your home as Ireland moves away from fossil fuels
• You plan to install solar PV, which can offset the electricity the heat pump uses

When Gas Might Still Be Acceptable

A gas boiler may still make sense if:

• Your home is poorly insulated and you cannot afford to insulate right now
• Your current boiler is relatively new and efficient (less than 10 years old)
• You have small radiators that require high flow temperatures — replacing them adds cost
• Your budget is very tight and you cannot bridge the upfront cost gap even with the grant

That said, the direction of travel is clear: Ireland plans to ban new gas boiler installations in new homes from 2025, and existing homes will increasingly need to switch to low-carbon heating. Installing a gas boiler now may save money short-term but could leave you facing another upgrade within 10–15 years.