A heat pump works reliably even at −15 °C
In winter, we look for an economical way to heat our homes. When choosing, we consider the price, options for combining the unit with other heat sources, efficiency, comfort and time savings, environmental impact, and above all low running costs. This article looks at the real operation of a heat pump installed in northern Slovakia, where winter temperatures can fall to −20 °C. We describe its features, actual winter costs and ways to combine it with other equipment.
Heat pump features
A monobloc air-to-water heat pump is simple to install. With a seasonal factor of 4.9, the ATTACK Inverter R32 is particularly suitable for new builds with underfloor heating, where it can heat a family home without difficulty at outdoor temperatures down to −15 °C. The ATTACK heat pump uses two heat sources: 1. The compressor circuit — its current output depends on the outdoor temperature. 2. An auxiliary electric source — a built-in electric heating element with a selectable output of 2 to 6 kW, depending on the system connection. The element provides the necessary heat output during exceptionally low outdoor temperatures (−20 °C), which may occur briefly in winter.
Which family homes are suitable for an air-to-water heat pump?
A monobloc air-to-water heat pump works most efficiently in well-insulated family homes with low heat loss. It is designed mainly for heating systems with a planned flow temperature of up to 55 °C. Underfloor heating is ideal. The pump can also work with radiators, provided they have a sufficiently large heating surface. Be cautious of claims that a low-temperature R32 monobloc air-to-water heat pump is a suitable replacement in an uninsulated family home. Such homes usually have radiators sized for the previous heat source and higher water temperatures (70–90 °C).
A radiator with a large heat-transfer surface.
Underfloor heating installation. Using a heat pump in an unsuitable home can give the technology a bad reputation. Heat pumps can also be used effectively when renovating older homes, but suitable measures are needed, such as adding quality insulation, replacing windows or fitting radiators with a larger heat-transfer surface.
A family home after renovation, insulation and window replacement.
A modern new build with an ATTACK Inverter R32 heat pump.
Heat pump running costs
In this particular family home in northern Slovakia, which has an A0 energy rating and 140 m² of underfloor heating, running costs are low because the conditions described above are met. The home was heated by an electric boiler that used 11,000 kWh per year. After a heat pump was installed, electricity use fell to 5,000 kWh, and after the first year the owners received a €750 credit on their energy bill. Their current monthly advance payment for the heat pump is €87.
Which equipment can be combined with a heat pump?
Photovoltaic panels can be an alternative heat source. A heat pump can be combined with different heat sources, such as biomass or gas boilers and solar thermal collectors. Photovoltaic panels can also supply electricity to the heat pump throughout the year. In spring, summer and autumn, depending on the size of the system, they can cover the required consumption and collect energy from the sun at virtually no cost. In winter, panel output depends mainly on sunlight, which is less intense than in summer, and on whether the panels are covered by snow. A well-designed photovoltaic system can cover part of the electricity needed, for example, to run a heat pump.
Photovoltaic panels.
The panels can also supply electricity to the heat pump.
Comfortable temperatures all year round
A major advantage over other heat sources is that a heat pump can be connected to fan coil units, which can cool in summer and heat in winter. This helps keep the home comfortable throughout the year.
The ATTACK Heating mobile app in cooling mode.
Heating with fan coil units and the ATTACK Inverter R32 heat pump.
Watch a video of the ATTACK heat pump in northern Slovakia
Quiet operation and convenient control through a mobile app make the ATTACK Inverter R32 a discreet source of heating and cooling all year round.
