What is an Air-to-water heat pump?

Please note: This article is for educational purposes only. Always consult a qualified heat pump installer before making any decisions about your heating system.

An air-to-water (AtW) heat pump uses electricity to absorb ambient heat from outdoor air and convert it into higher temperature heat. This heat can be used for space heating, cooling, and hot water in buildings. AtW heat pumps use an electrically powered compressor and refrigerant to transfer thermal energy between the outdoor coils and the water distribution system.

AtW heat pumps are highly efficient systems because they utilise existing environmental heat rather than generating heat through combustion. With proper design and sizing, these systems can achieve a coefficient of performance (COP) of 3-4. This means for every 1 kWh of electricity used, they produce 3-4 kWh of usable heat. This efficiency is roughly 3-4 times greater than conventional electric or gas boilers.

Contents

1. What is an Air-to-Water Heat Pump?
2. Businesses That Can Benefit
3. Potential Impacts
4. Important Considerations

What is an Air-to-Water Heat Pump?

An air-to-water (AtW) heat pump uses electricity to absorb ambient heat from outdoor air and convert it into higher temperature heat. This heat can be used for space heating, cooling, and hot water in buildings. AtW heat pumps use an electrically powered compressor and refrigerant to transfer thermal energy between the outdoor coils and the water distribution system.

AtW heat pumps are highly efficient systems because they utilise existing environmental heat rather than generating heat through combustion. With proper design and sizing, these systems can achieve a coefficient of performance (COP) of 3-4. This means for every 1 kWh of electricity used, they produce 3-4 kWh of usable heat. This efficiency is roughly 3-4 times greater than conventional electric or gas boilers.

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Businesses That Can Benefit

Air-to-water heat pumps are well-suited for businesses’ buildings that use hydronic heating systems, such as radiators or underfloor heating. They operate optimally in spaces with good insulation and the ability to maintain steady indoor temperatures. Buildings reliant on high temperature, quick heat, or frequent temperature fluctuations may require supplemental heating systems.

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Potential Impacts

• Energy Saving: Heat pumps can reduce heating energy consumption by 50-75% compared to electric resistance heating or gas boilers.
• Lower Emissions: By using electricity instead of onsite fossil fuel combustion, AtW heat pumps can reduce carbon emissions by up to 50%. Greater emission reductions are possible with continued grid decarbonisation.
• Cost Savings: The high efficiency and low maintenance requirements of heat pumps could lead to significant savings on lifecycle costs. While gas tariffs are cheaper initially, the long-term cost-effectiveness of heat pumps lies in their higher energy efficiency.
• Hot Water & Cooling: AtW heat pumps also provide efficient year-round hot water and summer cooling. Some units even allow simultaneous heating and cooling.
• Rebates & Incentives: Many utilities and governments offer rebates, tax credits, grants, and other incentives to install AtW heat pumps.

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Important Considerations

• Heat pumps operate best in well insulated spaces and where steady indoor temperatures over time are desirable.
• Electrical infrastructure may require upgrading when replacing a fossil fuel heating system.
• Installation is complex and should be done by qualified heat pump installers. Proper sizing and system design is crucial.
• The outdoor unit of the heat pump should be placed in a well-ventilated area with easy access for maintenance. Noise and visual impacts may require planning consent.
• Refrigerants used in heat pumps are an environmental concern as they are potent greenhouse gases. Refrigerants with lower global warming potential should be used.
• Heat pumps are inherently very reliable, but they do require periodic inspection and maintenance.

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