Unit1, Building 3, Port link Business Park, Port Road, Letterkenny, Co.Donegal

Air- Water Heat Pump

How does an air to water heat pump work?

An air to water heat pumps system consist of four major elements that allow the refrigerant to pass from the liquid state to the gas: a compressor, a condenser, an expansion valve and an evaporator.

1. A fan passes air over the evaporator; the refrigerant absorbs heat from the outside air. The refrigerant boils and evaporates at a low temperature giving us vapour.
2. The vapour passes into the compressor and compression increases the temperature.
3. The warm vapour is condensed is the heat exchanger and the rejected heat is passed onto the heating and hot water system
4. The condensed vapour returns to liquid, passes back through expansion valve, reducing pressure and temperature, ready to start cycle again

Benefits of Heat Pump


Reduced Energy Costs


One System for all heat sources


Climate Control


Safety Ensured


Energy Efficient


Eco Friendly


Drier Homes & Reduced Condensation

Advantages of Heat Pumps

  • Heat pumps save money. Heat pumps are cheaper to run than direct electric heating. They are cheaper to run than oil boilers and can be cheaper than running gas boilers. Because heat pumps can be fully automated they demand much less work than biomass boilers.
  • Heat pumps save carbon emissions. Unlike burning oil, gas, LPG or biomass, a heat pump produces no carbon emissions on site (and no carbon emissions at all, if a renewable source of electricity is used to power them).
  • Heat pumps save space. There are no fuel storage requirements.
  • Heat pumps are safe. There is no combustion involved and no emission of potentially dangerous gases. No flues are required.
  • Heat pumps require less maintenance than combustion-based heating systems.
  • Heat pumps can provide cooling in summer, as well as heating in winter.

Life Expectancy of Heat Pump

Like fridges and freezers, market experience has shown that life-cycles of fifteen years as a minimum, and a twenty-year life expectancy is not unrealistic.
How much less does it cost to run a heat pump than oil or gas?

In 2017 heat pumps are running at around half the cost* of oil and (natural) gas…. for many years they were more like one third of the cost of oil, but oil had come down in price to its present level…. Historically though, it has always been that the use of a heat pump has offered very significant savings and greater comfort due to the more sophisticated controls normally associated with the technology.

*SEAI’s domestic fuel cost comparison sheets are published bi-monthly and show up to date prices for different energy sources including heat pumps, oil gas etc. There you can see the price differences per kilowatt hour of the different fuels…. note that for comparison you should normally average the heat pumps running between rates ‘DD’ and night rate at 50/50.

Do heat pumps work when it’s very cold outside?

Yes. Proof of this is the fact that 20% of Swedish homes are heated by heat pumps!
In theory heat pumps can extract heat from any source, no matter how cold, but a warmer source allows a higher efficiency.
The relationship between the amount of energy used to run a heat pump and the amount of energy it produces is called the COP. This stands for Coefficient of Performance.
If a heat pump uses 2kW of electricity to produce 8kW of energy it has a COP of 4. Air source heat pumps in Ireland typically achieve a COP of 3 to 4. This means a home uses 1 unit or kWh of electricity for 4 units of heat produced.

What are the advantages of air source heat pumps?


Cost: Running costs are much less. Typically, they cost one third to half as much to run for each unit of energy produced.


One homeowner who replaced her oil boiler with an air source heat pump and saved over €2500 euro in energy costs after one year – while her electricity bill increased by €700, she didn’t have to pay for oil.


If homeowners install solar electricity PV panels they can reduce running costs even further.


Environment: Heat pumps are environmentally friendly reducing harmful particulate and carbon dioxide emissions by over 60% – 80%.


Comfort: Heat pumps are generally fitted with sophisticated controllers that maintain a chosen set point in temperature in the home. ‘We don’t have the peaks and troughs of temperature that we had with our oil boiler system,’ says one householder.


If heat pumps are also connected to the hot water tank they bring added home comfort.


‘We have constant hot water because the heat pump automatically tops it up,’ says another homeowner.

More Benefits for Heat Pumps:

• Cost effective way to meet Part L
• Low carbon heating solution
• Lower running cost than conventional heating systems
• Lower maintenance charges
• Provide 100% of heating & DHW demand
• Lower impact from fuel cost increases
• Proven Technology

Health & Safety Concerns

An air to water heat pump works without oil, gas or other hazardous substances, thus reducing the risk associated with these. Moreover, you don’t need a gas connection or a fuel tank. No risk of intoxication smell or pollution from leaking tanks.

Air to Water: Efficient

An air to water heat pump uses a sustainable energy source. It extracts heat from the outside air which is free.

The system consists of a closed circuit containing a refrigerant. A thermodynamic cycle is created through evaporation, condensation, compression and expansion. A heat pump “pumps” heat from a low to a higher temperature level.

The heat raised is transferred to the water distribution system (under floor heating, low temperature radiators and/or fan coil units for low temperature heating systems and high temperature radiators for high temperature heating systems) in the home via a heat exchanger.

A Daikin Altherma air to water heat pump delivers about 3kWh of usable heat for every kWh of electricity it uses. So this means that approximately 2/3 of your required home heating is free!