A Guide to Heat Pumps, Installation and Costs

Between 2013 and 2020, Ireland experienced a surge of approximately 50,000 residential heat pump installations. This has enabled many households to efficiently heat their homes, leading to substantial savings on electricity bills.

At Wattcharger, we take pride in staying ahead of the latest sustainability trends and ensuring our clients stay informed about Ireland's most exciting renewable developments. The realm of heat pumps is no exception. These carbon-free devices offer homeowners a multitude of benefits. Furthermore, for those seeking to enhance their home's Building Energy Rating (BER), heat pumps stand out as one of the most effective methods.

With the Irish State committed to installing 400,000 heat pumps across the country by the end of the decade, there are now fewer reasons than ever to overlook this exceptional renewable option.

Understanding Heat Pump Systems


Traditionally, Irish homes have relied on gas boilers or other fossil fuel-based sources for heating. In contrast to these emitting agents, heat pumps possess a unique ability to heat homes by harnessing existing heat in the air, using it efficiently instead of traditional heating methods.

While the method of heat emission might sound cutting-edge, it has been used in appliances like refrigerators and air conditioning units for decades. Heat pumps generate heat by circulating a substance called refrigerant, using a compressor to pump heat between two heat exchange chambers. The evaporator, the first chamber, evaporates the refrigerant at low pressure, absorbing heat from its surroundings. In turn, the condensing chamber condenses the refrigerant, releasing excess heat, which can then be dispersed throughout the home, providing warmth to radiators, underfloor heating systems, and the home’s hot water tank.

Though they share some broad similarities, three distinct forms of heat pumps exist:

  • Air Source Heat Pumps
  • Ground/Water Heat Pumps
  • Exhaust Air Heat Pumps

Air source heat pumps manipulate outside air to generate heat, circulating air and heating it with the refrigerant substance before spreading it across the home. These models demonstrate exceptional efficiency, sometimes providing returns of up to 400%.

Ground/water heat pumps utilize pipes, known as a ground loop, to burrow beneath the earth on the property. Circulating cold water through this subterranean network, the heated water is then fed to a pump above ground. There, the refrigerant substance pushes the heat out to the central heating system, functioning similarly to other central heating systems.

Exhaust air heat pumps, often placed in high-moisture areas, extract energy from already-warmed air and dispel unwanted, cooler air through a vent. While less popular, they can serve as built-in dehumidifiers, eliminating the need for additional ventilation fans.

The key to understanding heat pumps is that they transfer heat rather than generate it. This principle contributes to their efficiency and cost-effectiveness, whether the source is air or ground/water.

The refrigerant substance acts as the vehicle for efficient heat transfer. Electrical currents enable the refrigerant to circulate rapidly, absorbing and giving off heat. When the refrigerant goes through the compressor, it is squeezed, raising both pressure and boiling point, facilitating the seamless exchange of heat. Modern refrigerants like R-410A, less harmful than previous formulations, dominate the market.

In stark contrast to heat pumps, traditional gas boilers cannot transfer energy and must generate it through unclean methods. Boilers combust gas, propane, or heating oil to create heat, presenting fire hazards and potential air quality issues.

Beyond efficiency and safety concerns, the critical environmental difference between gas boilers and heat pumps is significant. While gas boilers emit substantial CO2, heat pumps are a zero-emission technology.

Despite the lower initial costs of installing a boiler, heat pumps present a better long-term investment. Additionally, various schemes exist to help homeowners adopt the more energy-efficient option.

Heat pumps are integral to the Irish Government’s plan to help 500,000 homes achieve a BER rating of B2 or better by 2030. The Sustainable Energy Authority of Ireland (SEAI) plays a leading role in making their rollout manageable and accessible.

Charged with advancing sustainable energy solutions, the SEAI has devised a grant to help homeowners adopt heat pump technology. The Heat Pump System Grant allows landlords and homeowners of homes occupied before 2021 to avail themselves of the scheme.

Under the grant, homeowners and landlords can receive up to €4,500 for an apartment or €6,500 for a house toward all three types of heat pumps. Moreover, the grant covers the €200 technical assessment carried out by a SEAI-registered technical advisor before applying. These figures will soon be contextualized by exploring the standard pricing of heat pump models and how they contrast with other heating methods.

Heat Pump Installation Process


The process of replacing a traditional boiler with a heat pump is known as retrofitting. Contrary to initial perceptions that this would necessitate a complete overhaul of the home’s heating system, a retrofit proves to be a surprisingly seamless process.

For an air source heat pump, which draws on outside air, placement is required both on the exterior and interior of the home. Selecting an exterior location is crucial, and it should offer shelter from the elements while considering the noise it may generate. The pump should be placed where it won't cause sound disturbances.

A registered installer conducts an assessment of the home's thermal transmittance, known as the u-value, ensuring it meets the standard. If it falls short, various insulation measures for walls, roofs, and doors are available.

The compressor, central to both the outside and inside unit installations, allows outside air to be compressed into warm air for the interior. Additionally, installers provide direct evaporating loops placed in a trench to satisfy the cooling load. For heating water, a heat exchanger adjacent to the water cylinder facilitates rapid heating.

In air source heat pumps, the indoor unit is mounted high on the wall for optimal positioning to blow heated air into the home. Once both units are installed, a hole is drilled through the wall to connect them. Internal units can be easily connected with existing wiring and pipework to heat sources like radiators, underfloor heating, and hot water pipes.

Regarding solar PV, heat pumps offer unique functionalities, allowing self-generated solar energy to power them. While connecting a solar power diverter and a heat pump to the same immersion element isn't typical, solar PV can be used in tandem with heat pumps. For more information, visit our recent post on the Government’s Microgeneration Scheme.

The pump size depends on the home size. An average 100-square-meter home may not need a pump larger than 4kW, while houses of 200 square meters or more might require an 8 or 10 kW output.

Like all useful equipment, heat pumps require regular maintenance for smooth operation. While an annual system assessment is recommended, more frequent checks are even better. Maintaining a proper assessment regime ensures that refrigerants harmful to the atmosphere do not leak and cause damage.

In conclusion, it's essential to use an SEAI-registered installation provider. This not only saves you from DIY headaches but is a requirement to avail of the grant amounts outlined above.

Costs and Operational Expenses


While there is no precise answer to the initial setup costs of heat pumps, industry averages in Ireland typically range between €3,500 to €7,500 for installation and €7,000 to €12,000 for the pump itself, before factoring in grant amounts.

While this may initially appear high, the marginal returns, when compared to more traditional methods, are, in fact, favorable. The cost per kWh of input is approximately €0.20 for both air and ground source heat pumps, compared to €0.06 per kWh for an average gas boiler and €0.12 for an oil boiler. Despite the lower prices of boilers, the efficiency of heat pumps balances the equation.

Switching to output figures, the superior efficiency of heat pumps, both air and ground/water, results in a cost of about €0.05 per kWh, compared to an output cost of approximately €0.70 for traditional boilers. As mentioned earlier, proper home insulation and accurate system size measurements maximize the system output figures, leading to a net financial benefit from transitioning to heat pumps.

Various factors, such as outdoor air temperature, can enable the heat pump to operate at maximum output capacity. Colder weather enhances the effectiveness of siphoning air through the condensation and evaporation matrix. It's crucial to note that while gas boilers may have seemingly lower costs, efficient management of heat pumps will likely result in long-term savings for property owners who operate these systems.

Energy Efficiency and Sustainability


In Ireland, the Building Energy Rating (BER) serves as a metric for a home's energy efficiency. This rating not only impacts the prospective value of the home but also holds implications for everyday life within your residence.

As demonstrated, the efficiency of traditional boilers pales in comparison to that of heat pumps. Heat pumps utilize emission-free technology to maximize output, ensuring that your home is energy-efficient. A high level of energy efficiency means that a significant portion of the energy you purchase is effectively utilized. In contrast, an inefficient system may result in substantial financial waste.

According to the SEAI's guidelines, a home with a rating of B2 or higher on its graduated scale meets benchmark requirements for renewable energy performance and home comfort. Once heat pumps are fully installed, the integration of solar panels offers an additional opportunity to enhance the home’s BER performance rating.

While extremely lower temperatures may pose challenges for heat pumps, there is no need to fear that very cold weather will degrade the pump system. A study from Oxford University confirmed that the efficiency advantage of heat pumps over traditional boiler systems persists even in temperatures at or approaching -30 degrees Celsius.

In an era of sustainable growth, consumers owe it to themselves to be aware of all available options. With heat pumps, homeowners have the opportunity to significantly boost their energy efficiency while incurring only a negligible financial impact.

Beyond being more environmentally sustainable than carbon-emitting boilers, the impact of any kind of heat pump on your home is undoubtedly positive. Although the technology comes with its setbacks and challenges, the prospect of heating a home sustainably using mere air should be an exciting concept for everyone.

Furthermore, various government grants like the heat pump grant have made it easier than ever to leap into sustainable heating. With a comprehensive system of guidelines and schemes at your disposal, there has never been a better reason to replace the boiler and significantly increase the energy efficiency of your home.

If you have any questions or want to explore your options regarding heat pump technology, do not hesitate to reach out to our team here at Wattcharger using the tool located below.

Blog Author: Adrian Dorney