Heat pumps can help Irish homes to become more energy efficient and save money on energy bills by taking advantage of the heat in the world around us.
This page will explain all of the basics of heat pump systems in Ireland, from how they work to their costs, benefits, and requirements to make your home heat pump-ready.
What is a Heat Pump
A heat pump is different from a boiler in that it doesn’t generate heat; it moves it. Heat is taken from the air, water, or ground outside of your home, and transferred inside.
Depending on how it is set up, a heat pump can connect to a central heating system to work with radiators and underfloor heating. Some heat pumps also directly heat the air in a room rather than using central heating.
How Heat Pumps Work
Heat pumps use electricity to extract heat from external sources for use in your home. A refrigerant with a very low boiling point is exposed to the outside heat source. Because of this low boiling point, anywhere from -40℃ to -70℃, it will absorb ambient heat from nearly any external source.
Residential heat pumps work using what is called the Vapour-Compression Cycle, where the refrigerant absorbs heat from outside, is compressed to increase its temperature and pressure, then releases that heat inside your home through a heat exchanger.
The biggest selling point of a heat pump is that it is far more efficient than other heating systems. A good air-to-water heat pump in your home should be able to produce 3 to 4 units of heat for every unit of electricity they use. This ratio of electricity usage to heat production is called the Coefficient of Performance.
Heat Pump Components
- 1
Heat Source: The external source of heat for the system is the air, ground, or a water source somewhere outside of your home.
- 2
Refrigerant: This is the substance contained within the piping of the heat pump, which extracts heat from the external source and then transfers it to the water or air inside your home.
- 3
Compressor: This is the heart of the system, fulfilling two roles. It compresses the refrigerant, raising its temperature and pressure; it also pumps the refrigerant through the system, allowing it to circulate between your home and the heat source.
- 4
Heat Exchanger: The heat exchanger is the mechanism through which heat is transferred between the refrigerant and an external medium. A heat pump has two heat exchangers, the Evaporator and the Condenser. The evaporator absorbs heat from an external source and transfers it to the refrigerant. The Condenser transfers heat from the refrigerant to the end source in your home.
Heat Pump Cycle
- 1
Evaporation (Absorbing Heat From Outside): Outside of your home, the Evaporator extracts heat from the external source, causing the partly-liquid, partly-gas refrigerant to vaporise. It is now a low-pressure, low-temperature gas.
- 2
Compression (Transforming to High Heat/Pressure): The refrigerant is then sent through the compressor, which does as its name suggests, causing it to drastically increase in temperature. It is now a high-temperature, high-pressure gas.
- 3
Condensing (Transferring Heat to Inside): This very hot gas then goes through the Condenser, one of the two heat exchangers in the cycle. The very hot condenser allows some of the heat to be lost to whatever medium it is heating. After this, the refrigerant is now cooler, but still under high pressure.
- 4
Expansion (Further Reduction of Heat & Pressure): The refrigerant passes through the expansion valve, lowering its temperature further and reducing the pressure it is under. It is now in a semi-liquid, semi-gaseous state and returns to the start of the cycle at the evaporator.
Heat Pump Efficiency
A heat pump uses electricity to power its mechanisms, but does not use any fuel to create heat directly. Relying on natural heat sources stored in the air, water, or ground allows them to be far more efficient than boilers or storage heaters.
The efficiency of a heat pump is called its Coefficient of Performance (CoP). The higher the CoP a heat pump has, the better. Ideally, a heat pump should aim for a CoP of 3 – 4, meaning that it will make up to 4 units of heat for every unit of electricity used in its operations.
Factors Affecting Heat Pump Efficiency
Heat Source Temperature: At lower temperatures, heat pumps have to work harder to extract heat from the external environment. This is especially true of air source heat pumps.
- System Sizing: A heat pump must be properly sized for the needs of your home. Too small and it must work harder to maintain the proper temperature. Too large and it will be turning on and off more frequently, using up more power short cycling.
Refrigerant Type: There are multiple types of refrigerants used in heat pumps. These can perform better than others at different temperatures. Choosing the right refrigerant depends on your heating needs.
Factors to Consider Before Getting a Heat Pump
Heat pumps operate at a lower flow temperature than oil or gas boilers, but make up for it by running 24/7 to keep the temperature up. However, this lower flow temperature means that heat loss in your home has a greater impact. If your home has a poor Heat Loss Indicator, then a heat pump will struggle to keep the temperature up.
Older heating systems may need significant upgrades before they are suitable for a heat pump. This can include narrow radiators and pipes that rely on higher-pressure water
Heat pumps use electricity rather than oil or gas, and electricity always has a higher cost per kWh than fossil fuels. With your heat pump running 24/7, this will considerably increase your electricity usage.
It’s easy to forget about switching electricity plans and providers once a year, but it really is the best way to get a good deal. This becomes much more important when electricity is now your main space heating fuel.
Types of Heat Pumps
There are multiple varieties of heat pumps. The main things which distinguish them are the heat source they rely on and how they heat your home.
Air-to-Water Heat Pumps
Heat Source: Heat is drawn from the air outside your home by an external fan unit.
Heat Provision: That heat is transferred to a hot water tank, which then supplies the central heating system in your home.
Strengths: The outside unit takes up little space, and it can be the simplest way to retrofit a home with an existing central heating system.
Weaknesses: It may require you to replace your radiators or piping if they are old/narrow.
Air-to-Air Heat Pumps
Heat Source: The air outside of your home runs through the external fan unit.
Heat Provision: The heat pump piping connects to one or more fan units blowing hot air through the room.
Strengths: Doesn’t require any replacement of the central heating system. No need for a large water tank. It can be used to cool a room as well as heat it.
Weaknesses: Requires multiple internal units to heat an entire home. Pipework can be more extensive than an air-to-water system.
Ground Source Heat Pumps
Heat Source: Heat is drawn from the ground using either a large loop of buried piping or a deep borehole.
Heat Provision: The ground source pump connects to either an internal water tank and central heating system, or internal fan units.
Strengths: The ground can store heat much more effectively than the air, giving you a more reliable source to draw on. No large external unit is required.
Weaknesses: Requires a massive loop of piping to get enough heat from the ground. This needs a large area of ground available, with large and expensive excavation works. Leaks are more difficult to detect and fix.
Water Source Heat Pumps
Heat Source: Heat is extracted from a body of water, such as a river or lake.
Heat Provision: The water source pump connects to either an internal water tank and central heating system, or internal fan units.
Strengths: Water retains heat better than air, ensuring a more consistent efficiency for your heat pump.
Weaknesses: Requires a nearby body of water to work. They may also need more maintenance depending on the system setup.
Cost of Heat Pumps in Ireland
The median cost of a heat pump in 2025 was between €14,000 and €17,000 without any grant, with costs varying depending on the size of the property involved. Larger homes will need a more powerful system, which will raise the price significantly.
The vast majority of Irish homes with heat pumps are getting an Air-to-Water system, as these integrate easily with central heating and take up less space.
A ground or water source heat pump may cost significantly more than the figures above. This is because there is far more work involved in getting them installed, and setting up the heat source.
If your home needs extensive upgrades to make it suitable for a heat pump, this will significantly add to the overall price of the home improvements.
Grants for Heat Pumps in Ireland
The SEAI provides grants of up to €12,500 for homeowners to install heat pump systems. The value of the grant is dependent on whether you live in a house or apartment, and the type of heat pump.
There are three elements to the current SEAI grant for heat pumps:
Heat Pump System: Up to €6,500 for the heat pump itself.
Central Heating Upgrades: Up to €2,000 for upgrades to radiators, pipes, or other parts of the heating system.
Renewable Heat Bonus: €4,000 if you are swapping out an oil or gas boiler, solid fuel heating system, or electric storage heating system.
These grants are available for homes built and occupied before 2021 if its heat loss is low enough.
Built After 2007: It is assumed that you meet the heat loss requirements.
Built Before 2007: It must have a Heat Loss Indicator (HLI) which is less than or equal to 2.3 W/Km²
How much can you save with a heat pump in Ireland?
A heat pump can potentially save you a lot of money on heating bills compared with other heating systems due to their high efficiency.
Whether a heat pump will save you money, and how much it can save depends on the following factors:
Heating Requirements: How large your home is and how hot you like to keep it. Heat pumps are more efficient at lower temperatures.
Heat Loss: How well protected is your home against heat loss through walls, windows, the roof, and other elements of the building fabric.
Electricity Prices: The price you pay per kWh of electricity for your home.
Heat Pump Efficiency: A heat pump should be able to produce 3 – 4 units of heat per unit of electricity used. The efficiency of a heat pump will depend on it being properly sized for your home, and vary between different brands and models.
An energy-efficient home, with good insulation and low levels of heat loss, may save upwards of 30% on its heating bills.
Benefits of a Heat Pump in Ireland
There are many benefits to switching to a heat pump for your home. They can save you money by using less energy, reduce your carbon footprint, and keep you more comfortable than a boiler.
Savings on Heating
With a properly insulated home, you can save 30% or more on your heating bills with a heat pump compared to an oil or gas boiler.
More Consistent Temperatures
Heat pumps work by keeping your home at a constant temperature, unlike a boiler, which can deliver spikes of heat by turning on for an hour and then letting the house cool off again.
Environmentally Friendly Heating
Heat pumps do not use any fossil fuels directly, and their high efficiency means that any emissions from electricity will be lower than oil, gas, or other electric heating systems.
Increased Property Values
Having a heat pump installed will improve the Building Energy Rating of your home, which can significantly raise its value.
Cooling Capabilities
Some air source heat pumps, particularly air-to-air systems, can also be operated in reverse. This allows them to cool your home down in summer.
FAQs
Yes, you can use solar panels in conjunction with a heat pump, and it is a very good idea. Solar panels are at their most productive during the day, which is also when electricity tends to be the most expensive. Combining solar and grid power can be the most affordable way to operate a heat pump.
Yes, you can get a heat pump in an apartment building if you have permission. Apartment buildings will sometimes use centralised heating systems, which can include heat pumps. Air Source heat pumps can also be installed on the outside of a building for individual units.
Yes. The refrigerant in a heat pump will have a boiling point well below 0℃. This means that a heat pump can extract heat from outside air even when the temperature is -15℃ or lower.
For the average Irish home, a heat pump will use between 2,000kWh and 4,000kWh of electricity each year. This varies based on the size of your home and its energy efficiency.
Yes, if you have a well-insulated home, then heat pumps can be excellent value in Ireland. Winters in Ireland rarely drop much below freezing overnight, and the average lowest temperature is 5.1℃. This is well within the operating range of any heat pump.
Short cycling refers to when a heat pump is turning on and off too frequently, with much shorter cycles. This reduces the lifespan of the heat pump by wearing out the compressor more quickly.
Yes, heat pumps are far more efficient than an electric boiler, producing 3 – 4 units of heat for every unit of electricity used. Electric boilers have at most a 1:1 ratio of energy used to heat produced.
A heat pump should have a lifespan of at least 15 years, but it can last much longer if they are properly serviced and maintained.
No, with the vast majority of heat pumps a poorly insulated home is not suitable. High-temperature heat pumps may work better in homes with greater heat loss and older heating systems.
You may need to replace your radiators with new wide panel radiators depending on the flow temperature of your heat pump, and the temperature you desire.
Typical no. Planning exemptions exist for ground and air source heat pumps as long as they meet certain requirements. Heat pumps must not alter the ground level by more than 1m compared with the adjoining ground.
Air Source heat pumps must be located at least 50cm from the edge of the wall or roof where they are located. The total area of the external unit must also not exceed 2.5sqm for homes. Noise levels at the nearest party boundary must also not exceed 43db(A).
Heat pumps are complicated systems that can be very difficult to install without the proper expertise. If your heat pump refrigerant is R-290 (Propane) then there is an added risk as this is a very flammable substance.
Yes, but an older home will require either a lot of work to improve its insulation for regular heat pumps, or a high-temperature heat pump to match the water temperature output of a boiler.
