Air-source Heat Pump
An air-source heat pump is a sensible investment and, if used correctly, can save you money on heating costs. Minor adjustments and maintenance ensure energy-efficient operation of the air-source heat pump. In electrically heated houses, its efficient use can save up to 30% of total energy consumption.
An air-source heat pump (ILP) transfers heat energy from the outside air and releases it directly into the indoor air. An air-source heat pump can also be used to cool indoor air. Air-source heat pumps are suitable for all types of houses.
A single air-source heat pump can typically provide 30-60% of space heating energy. The size of the heat pump, the installation of the indoor unit, the way the unit is used and the layout of the room all affect the amount of savings that can be achieved.
The amount of heat produced by an air-source heat pump depends on the outdoor air temperature. The lower the outdoor temperature, the less heat can be produced. The performance of air-source heat pumps has improved and good quality equipment can provide significant heat even at outdoor temperatures as low as -25°C.
A good quality heat pump can provide the heat a building needs during mild winters, but an air-source heat pump also needs an independent backup form of heating that is activated by a thermostat when needed.
Efficient use of an air-source heat pump saves electricity
- Make sure that the air source heat pump is used before other heating systems.
- Keep the appliance on either the heating or cooling setting, not the automatic setting.
- If the actual heating system is on at the same time, set the indoor temperature setpoint for the main heating system 2-4 °C lower than the setpoint for the air-source heat pump. For example, radiator thermostats 17-19 °C and heat pump 21 °C.
- Lower the temperature settings for the period of absence (including main heating). When you return home, use the high fan power of the air source heat pump to quickly raise the temperature.
- Do you use a fireplace or stove for supplementary heating? Check that the automatic cooling function of the air source heat pump is switched off.
- Switch on the heating function in autumn. Set the air-source heat pump to your preferred, energy-efficient level and lower the setting of parallel heating devices (e.g. electric radiators) by a few degrees.
- Use the cooling function if necessary in hot weather.
Purchase and use of an air-source heat pump
Air-source heat pumps are easy to install in all types of houses, both new and old. Air-source heat pumps do not require special structural solutions and are the cheapest of the various heat pump options in terms of investment.
An air-source heat pump is suitable for a spacious property. One indoor unit of an air-source heat pump usually distributes heat over an area of about 30-100m2, depending on the type and size of the building. Partition walls and complex building structures limit heat transfer to other rooms, so in particularly challenging building structures it may be worthwhile to have more than one indoor unit.
The indoor unit of an air source heat pump is usually placed in the wall of an open space more than 20 cm below the ceiling, more than 2.2 m above the floor and in two-storey houses in the staircase. When positioning the indoor unit, it is important to take into account the possibility of the warm air spreading to other apartments. The outdoor unit is fixed to the wall of the house or to the ground, above the snow line, at least 80 cm above the ground.
The air-source heat pump is well suited as a parallel heating system to oil or direct electric heating, or as a main heating system for a garage, for example. The use of a pump effectively reduces the need for heating energy produced by a parallel heating system.
Operation of an air-source heat pump
An air-source heat pump consists of an outdoor unit and one or more indoor units. The outdoor unit circulates outside air through it and cools it when the unit is in heating mode. The recovered heat is transferred by a compressor to the indoor unit, which releases the heat into the indoor air. Air-source heat pumps can also be used to cool indoor air
The outdoor unit of an air-source heat pump has an evaporator that takes heat from the outdoor air circulating through the outdoor unit. The heat is transferred to the indoor unit of the air-source heat pump via a refrigerant. The indoor unit circulates the indoor air of the house through it and heats it.
An air-source heat pump is generally not suitable as the only heating device in a building, because its efficiency and power output decrease as the outdoor temperature decreases, and the air does not usually distribute the temperature effectively enough to all rooms. The smaller the temperature difference between the indoor and outdoor air, the more efficient the heat pump.
Air-source heat pumps provide about 50% less power at -20 degrees Celsius below zero than at +7 degrees Celsius, where the power and heat coefficient of the unit is stated in the standard. In the hardest frosts, the efficiency of an air-source heat pump can drop to almost the same level as electric heating. Currently, the energy label of an air-source heat pump indicates, among other things, the energy class and the SCOP value, which is closer to the annual coefficient of performance than the COP value.
Cleaning and maintenance of the air source heat pump
The air heat pump filters the air, provided that the filter is cleaned regularly. Tips for cleaning your air-source heat pump:
- Clean the filters in the indoor unit by vacuuming them regularly, preferably once a month. The filters can be easily removed from behind the cover and vacuumed lightly clean.
- Also clean the outdoor unit, and monitor the defrost and condensation water regularly.
- Keep an eye on the outdoor unit in winter and carefully clean off any snow and ice that accumulates.
- Basic maintenance of the air source heat pump every few years, especially the heat exchanger coil and fan.