www. refrigerationandaircon. co. za RACA Journal I October 2025 19
Feature
pump can reach a COP close to 4, meaning it can deliver up to four units of heat for every unit of electricity consumed.
This high efficiency is achieved by moving heat rather than generating it, dramatically reducing energy use – especially when compared to fossil fuel-based systems.
Image supplied by York
Water-cooled heat pump.
WHY THE AIR FROM A HEAT PUMP DOESN ' T FEEL WARM It’ s true that air supplied by a heat pump may not feel warm to the touch. Air at 35 ° C is enough to heat a room but feels cool relative to our body temperature( about 37 ° C).
To compensate, some systems are set to trigger an auxiliary( backup) heat source, such as electric resistance heating, to make the air‘ feel’ warmer. While this may improve subjective comfort, it reduces the overall system efficiency. It ' s important to educate users that a lower outlet temperature does not mean the system isn’ t working— it’ s often a sign that it is working efficiently.
Image supplied by York
Complex heat pumps – water cooled.
DO HEAT PUMPS GENERATE HEAT? Contrary to what the name might suggest, heat pumps do not
generate heat – they move it. Using the refrigeration cycle, heat pumps transfer thermal energy from a cooler area( like outdoor air, even in winter) to a warmer space inside a building.
The process involves a refrigerant absorbing heat from the outside air, even in low temperatures. As the refrigerant changes from liquid to gas, it is compressed, raising its temperature and pressure. This hot gas then releases heat indoors as it condenses back into a liquid, ready to repeat the cycle.
What sets modern heat pumps apart is their ability to operate efficiently at much lower outdoor temperatures than earlier models, making them viable in a broader range of climates.
ARE HEAT PUMPS EFFICIENT? Heat pumps are among the most efficient heating systems available today. Their efficiency is commonly measured using the Coefficient of Performance( COP). A COP above 1 indicates that the system delivers more heat than the electrical energy it consumes. Traditional electric furnaces typically operate at or below a 1:1 efficiency ratio, depending on how much energy is lost during combustion and ventilation. In contrast, an inverter-driven heat
DOES EVERY ROOM NEED ITS OWN DUCTLESS UNIT? Ductless mini-split systems often use individual indoor units connected to a single outdoor compressor, allowing for zoned temperature control. While this setup can be ideal for retrofits or homes without ductwork, it’ s not always the best solution.
A common issue is oversizing, where a unit is too powerful for the room it serves. Oversized systems can short-cycle, leading to poor humidity control, uneven temperatures, increased wear on components and reduced comfort.
Correct sizing according to a detailed load calculation is critical. This ensures the system matches the specific heating and cooling requirements of each space. In many cases, a mix of ducted and ductless units may be more effective, especially for larger areas or open-plan designs.
DO HEAT PUMPS LEAK REFRIGERANT EASILY? Refrigerant leakage is not inherent to heat pump technology— it’ s typically the result of improper installation. Most leaks occur at flared connections where copper tubing is joined. If a flare is not formed or tightened correctly, or if torque specifications are ignored, leaks can occur.
Proper training, modern tools and attention to installation best practices can prevent these issues. When installed correctly, heat pump systems are reliable and maintain their refrigerant charge over many years of service.
PERCEPTIONS THAT HEAT PUMPS ARE NEW, COMPLICATED AND EXPENSIVE Inverter-driven heat pumps have been in use globally for decades and are a proven technology. Their perceived complexity often stems from unfamiliarity among some HVAC professionals, rather than the actual installation process.
www. refrigerationandaircon. co. za RACA Journal I October 2025 19