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Air source heat pumps use the ambient energy in outside or exhaust air for heating, and preparation of hot water.


(Also commonly referred top as Air-to-Water Heat pumps.) 


These compact machines gather heat from the outdoor air and distribute the heat through water based systems such as underfloor heating and radiators. Recent advances in this technology have made air to water heat pumps a very popular choice in the mild climate of Ireland.


They have low acquisition costs as there is no geothermal drilling or surface collectors required under the soil.  They are a very popular choice for new-builds to allow compliance with Irish building regulations as a stand-alone solution.


With the aid of a ground source heat pump, solar energy stored in the ground can be collected and used to heat your home.


Often referred to as geothermal heating, the heat collected is mostly from the sun in fact and not the earth’s mantle! The heat pump extracts heat from the ground either by  a vertical or horizontal collector. Heat is commonly distributed by underfloor heating or radiators. Ground source heat pumps can also be used for passive and active cooling of buildings, whereby the excess summer heat is removed by the floor heating or fan coil units and stored in the rock for use later!


For air-tight, low energy builds, where ventilation is a must, an Exhaust Air Heat-Pump may be an ideal choice. This will re-cycle the heat from your house’s ventilation system. These machines are ideal for apartments (there are no outdoor parts) and more compact air-tight low energy or passive homes. Air is drawn through ducts to the heat pump from the bathrooms, utility and kitchen areas. The cold waste air is discharged to outside through another duct, and condensation to a drain.

Not only that, the additional heat generated internally from lighting,
people and domestic appliances is also utilised through heat recovery. Some exhaust air heat pumps can also draw additional air in from outdoors to harness additional energy too.


If ground water is available and easily accessible, it can be utilized as a heat source due to the fact that it has a temperature of between 7 and 12 °C all-year round. It is advisable not to pump water for single and two-family houses from a depth greater than approximately 15 m. This would lead to expenditures being too high.

A distance of approximately 10 to 15 m should be kept between the withdrawal point (supply well) and the reinsertion point (deep-well) and furthermore the flow direction should be taken into consideration in order to avoid a “flow short-circuit”.


The heat is retrieved from the outside  air through an outdoor module, where the refrigerant, which circulates in a closed system, transfers the heat from the heat source (outdoor air) to the indoor module. 


These heat pumps provide ideal stand-alone solutions especially suited to small garden rooms, home offices and apartments and do not use a water-based heating system such as radiators, just the indoor module(s), usually located at high level on a wall or even ceiling mounted. 

Larger versions with multiple indoor units are often seen in hotels etc.

Most can also be reversed for cooling in summer too.

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