What Is a Heat Pump?

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Cormac is Selectra.ie's energy expert along with being the chief content and editorial manager for the website. His aim is to help find the best deal for you and your home energy needs so that you save money on your annual bills. His knowledge and experience of the Irish energy market allows him to offer the best advice and insight into current prices, emerging trends and overall energy saving tips.

Updated on 13/11/2025

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A heat pump is a highly efficient device that transfers heat from one place to another (typically the air or ground) to heat your home and water, rather than generating heat by burning fuel. The average installed cost for a system in Ireland ranges from €12,000 to €28,000 before the SEAI grant of up to €6,500 is applied, and drastically reduces long-term running costs compared to fossil fuel systems.

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What Is a Heat Pump, and How Does It Work?

At their core, a heat pump is a device that transfers heat energy from one place to another, rather than generating it by burning fuel.

They use a small amount of electricity to move a large amount of heat. Even when the air outside is cold, a heat pump extracts heat energy and transfers it inside your home to heat both your rooms and your hot water, replacing traditional home heating systems.

Air-to-Water vs. Ground-Source Heat Pumps

In Ireland, the two primary types for residential use are:

Air-to-Water Heat Pumps (ASHP): The most popular choice. They extract heat from the outside air and transfer it to your water-based heating system (radiators or underfloor heating).
Air-to-Air Heat Pumps (AAHP): It works by transferring this heat directly into your home's internal air via blower units, providing both instant heating in winter and efficient cooling in summer.
Ground-Source Heat Pumps (GSHP): These use underground pipes to absorb heat from the earth, which remains at a relatively constant temperature year-round. While more efficient, they have a higher installation cost and require significant land for the collector loops. Ground-Source is sometimes referred to as geothermal heating.

Is My Home Suitable for a Heat Pump Ready?

For a heat pump to be efficient and cost-effective, your home must retain heat effectively.

This is the single most important factor for success and is mandatory for the SEAI grant.

The Heat Loss Indicator (HLI) Requirement

To qualify for the SEAI heat pump grant, your home must meet a minimum energy efficiency standard, measured by the Heat Loss Indicator (HLI).

The HLI is the total heat loss (through fabric and ventilation) divided by the floor area, measured in Watts per Kelvin per square metre ($W/(K \cdot m^2)$).

The SEAI Target: Your home's HLI must be **less than or equal to 2.0 $W/(K \cdot m^2)$**. In some specific, non-cost-optimal cases, up to 2.3 $W/(K \cdot m^2)$ may be accepted.
What it Means: If your HLI is too high, it means heat is escaping too quickly. A heat pump, which runs at a lower temperature than a boiler, would have to work too hard to keep the house warm, leading to high running costs.

The SEAI Technical Assessment

Before you can apply for the grant, you must hire an independent, SEAI-Registered Technical Advisor (grant aid of €200 is available for this).

They will:

Conduct a BER assessment to determine your current HLI.
Provide a detailed report outlining the required fabric upgrades (e.g., insulation, windows) to bring your HLI to the acceptable level.

You must complete these fabric upgrades before the heat pump installation to ensure system performance and grant eligibility. If your home has a BER lower than a B2, it will likely need significant work, such as cavity wall insulation or attic insulation, to get the full benefit of your new heat pump system.

Radiator and Cylinder Compatibility

Radiators: Since heat pumps work best at low flow temperatures (35°C to 45°C) versus a boiler's 70°C, your existing radiators may not be large enough to heat the rooms effectively. The Technical Advisor will assess your radiators. You may need to install larger low-temperature radiators or opt for underfloor heating.
Hot Water Cylinder: You will almost certainly need to replace your hot water cylinder with one that has a larger surface area coil, designed to work efficiently with the heat pump's lower flow temperature. This replaces the need for costly and inefficient immersion heaters.

How Much Do Heat Pumps Cost?

The final cost to the homeowner is heavily influenced by the SEAI grant and the extent of required retrofit work.

You can expect to pay anything between €1,000 to over €20,000 for a heat pump in Ireland, depending on the type and complexity of the system and whether you qualify for an SEAI grant.

SEAI Heat Pump Grants (Individual Application)

SEAI Grant Offers
System Type	SEAI Grant Value	Grant Status
Air-to-Water / Water-to-Water	€6,500	Available
Ground-Source	€6,500	Available
Air-to-Air (Space Heating Only)	€600	Available
Technical Assessment	€200	Available

Source: SEAI Last Updated: January 2025

If you are opting to use the SEAI grant scheme, you must use a certified contractor to receive the grant.

Estimated Installation Costs (Excl. Grants)

These ranges cover the unit, cylinder, installation, electrical work, and minor plumbing.

They exclude major fabric upgrades (insulation, windows) which are grant-aided separately.

Heat Pump Cost
Heat Pump Type	Total Installed Cost (Excl. Grant)	Typical Homeowner Cost (Post-Grant)
Air-to-Water	€12,000 - €18,000	€5,500 - €11,500
Ground-Source	€18,000 - €28,000	€11,500 - €21,500

Tip: You can apply for grants for insulation and fabric upgrades (e.g., walls, attic, windows) **separately** from the heat pump grant.

Many companies who specialise in heat pump installation can offer you a quote on how much it will cost to install a system on your property.

What Are the Running Costs of a Heat Pump?

The true measure of a heating system's value is its annual running cost.

Understanding the long-term commitment helps assess the true value of the investment, especially regarding your long-term energy bills.

This table compares the cost of delivering 12,000 kWh of heat energy—the approximate annual requirement for space heating and hot water in a well-insulated, three-bedroom Irish home.

Heat Pump vs. Other Heating Systems
Heating System	Unit Price (c/kWh)	Typical Efficiency (SPF/SEFF)	Energy Input Required (kWh)	Estimated Annual Cost
Air-to-Water Heat Pump	35.0 c/kWh (Electricity)	350% (SPF 3.5)	3,429 kWh	€1,200
Ground-Source Heat Pump	35.0 c/kWh (Electricity)	400% (SPF 4.0)	3,000 kWh	€1,050
Natural Gas Boiler	14.0 c/kWh (Gas)	92%	13,043 kWh	€1,826
Oil Boiler (Kerosene)	11.0 c/kWh (Oil)	90%	13,333 kWh	€1,467
Direct Electric Heating	35.0 c/kWh (Electricity)	100%	12,000 kWh	€4,200

Estimates based on average Irish energy prices in 2025. Costs exclude standing charges and maintenance fees, which vary by supplier and system.

Annual Maintenance and Running Costs

Annual servicing by a registered professional is strongly recommended to ensure peak efficiency. Costs typically range from €100 to €250 per year. This is less than service for a storage heater or boiler.

A heat pump eliminates your need to heat your home using fossil fuels such as oil and gas. How much you save is dependent on multiple factors, but the average household could save between €500 and €1,500 per year.

Heat pumps are considered to be better for the environment. They still use electricity to run, which means they are only ‘green’ if your home is fed by 100% renewable electricity, or you use solar panels.

Expected Lifespan and Warranty

A well-maintained heat pump system typically lasts 15 to 20 years, significantly longer than the average gas or oil boiler.

Manufacturer warranties usually cover the unit for 3 to 7 years. However, keeping this warranty valid almost always requires annual professional servicing.

What Are the Pros and Cons of Heat Pumps?

Weighing the advantages against the disadvantages is essential for deciding if a heat pump is right for your home in Ireland.

Pros (Advantages)

High Efficiency (COP): They are significantly more efficient than traditional boilers, converting 1 unit of electricity into 3-4 units of heat.
Lower Running Costs: Generally cheaper to run than oil or LPG boilers, leading to long-term savings on energy bills.
Long Lifespan: Systems are durable and typically last 15-20 years or more with proper maintenance.
Environmental Impact: Zero on-site carbon emissions, reducing your carbon footprint, especially when powered by green electricity.
Dual Functionality: Many models (especially Air-to-Air) can provide efficient cooling in the summer months.
Consistent Comfort: Provide a steady, reliable source of heat, maintaining a comfortable temperature 24/7.

Cons (Disadvantages)

High Upfront Cost: The initial installation cost is significantly higher than a new gas or oil boiler, even with the SEAI grant.
Home Suitability Required: Only efficient in homes with excellent insulation and air-tightness (HLI $\le 2.0$ or BER B2). Retrofitting older homes is mandatory.
Radiator Upgrades: May require the costly replacement of existing radiators with larger, low-temperature units.
Lower Flow Temperature: The system works best at a low, constant temperature and cannot provide rapid heat boosts like a traditional boiler.
Installation Complexity: Requires a full system redesign (Technical Assessment), which can be complex and invasive.
Noise: The external fan unit can generate noise, which must be considered in relation to neighbours and planning exemptions.

Heat Pump FAQs

Modern air-source heat pumps are relatively quiet, often operating between 40 and 55 decibels (dB)—similar to a quiet refrigerator. Installation must comply with planning exemptions that limit noise at the boundary to 43 dB(A).

In most cases, no. Conditional Planning Exemptions apply for air-source heat pumps provided the installation meets certain criteria (e.g., unit size, distance from the boundary, and noise limits). Ground-source heat pumps generally do not require planning permission unless they involve extensive groundwork in a protected area.

Yes. A correctly sized and installed heat pump in a properly insulated home (HLI $\le 2.0$) will maintain a comfortable temperature 24/7. Heat pumps work best when running consistently at a lower flow temperature, providing steady background warmth rather than bursts of high heat.

Yes. With the right modifications, you can integrate a heat pump into your current heating system. We recommend getting advice from your plumber or heat pump installer to see what changes are necessary.

Radiators can be used with heat pumps, but they may need to be exchanged to get the full benefit due to a heat pump's steadier, lower temperature distribution. Your heat pump installer will recommend any changes needed.

Learn More About Energy Saving Our energy guide articles contain lots of useful information on saving energy, lowering costs and how to have a more positive impact on the environment.