What 17 real-world installations by Enevator Store have taught us:
New insights from over 195,000 operating hours across Europe
More and more buildings are being retrofitted to reduce energy consumption and CO₂ emissions. Heat pump water heaters play an important role in this. Yet questions remain in the market about their real-world performance.
How much ventilation is really needed? How do conditions in the mechanical room affect efficiency? And is a heat pump water heater also suitable for existing buildings where ideal installation conditions aren’t always present?
To answer these questions, we visited 17 Enevator Store installations across Europe. The locations ranged from hotels and offices to healthcare facilities, industrial buildings, and public facilities. Together, these installations account for more than 195,000 operating hours and over 22 years of practical experience.
The results provide valuable insights into how Enevator Store performs under real-world conditions and demonstrate that heat pump water heaters can be successfully used in more applications than is often assumed.
Looking Beyond the Design Guidelines
Enevator Store utilizes heat from the ambient air to efficiently produce hot water. To maximize the heat pump’s efficiency, we recommend adequate ventilation and a suitable utility room.
However, during site visits, it became apparent that many installations functioned excellently even when these ideal conditions were not fully met. Several systems were installed in relatively small utility rooms, while other locations had limited or even no ventilation.
Nevertheless, the real-world results were remarkably consistent: users reported that the hot water supply functioned reliably and met their daily needs.
That does not mean ventilation is unimportant. Larger, well-ventilated spaces remain the best foundation for maximum efficiency and a high heat pump contribution. At the same time, the results show that the Enevator Store can also be successfully implemented in buildings that, based on traditional design criteria, are not immediately considered suitable for a heat pump water heater.
Proven reliability: sufficient hot water always available
Ultimately, a hot water system is not just about energy efficiency, but above all about comfort and availability. Is there enough hot water available during peak times? And does that remain the case throughout the day?
That is precisely why user feedback was one of the most valuable findings of the study. At all 17 locations visited, Enevator Store proved capable of reliably meeting daily hot water needs. No recurring complaints were reported regarding comfort, capacity, or the availability of hot water.
Whether in hotels, offices, healthcare facilities, or industrial buildings, the experiences were remarkably consistent. Users could count on a stable hot water supply that met daily demand.
This real-world experience confirms that a well-designed and properly sized Enevator Store system not only saves energy but also delivers the comfort and reliability that users expect every day.
Why 60°C Is Often the Best Choice
The field data showed that the selected storage temperature has a significant impact on the system’s performance.
Systems with a maximum storage temperature of 60°C consistently achieved a higher heat pump contribution and required less electric backup. In systems set to 65°C, the proportion of electric heating increased noticeably, causing the overall efficiency to decrease.
The explanation is simple. At a setpoint of 60°C, the heat pump can continue to operate efficiently under a wider range of conditions. As a result, electric backup heating needs to be used less frequently, and a larger portion of the required heat is supplied by the heat pump itself.
For most applications, 60°C therefore offers the optimal balance between energy efficiency, efficiency, and hot water comfort.
When 65 °C or higher is required
A storage temperature of 60 °C yields the highest heat pump contribution in many situations. For point-of-use systems, this is often an excellent choice. However, that does not mean that 60 °C is always the best solution for the entire building.
Long pipe runs and large circulation networks often require a higher temperature. This is because, due to Legionella regulations, the return line must reach 60 °C when it returns to the unit. In addition, various applications, such as industry, the food industry, and livestock farming, regularly require a higher hot water temperature.
The Enevator Store is also capable of delivering these higher temperatures. If the heat pump does not have sufficient capacity to reach the desired temperature, the integrated electric heating elements automatically kick in. This ensures that hot water comfort is maintained. However, with a higher setpoint, the likelihood increases that the electric heating elements will be activated more frequently. This makes it possible to reliably maintain an adequate supply of hot water even when higher temperature requirements are in place.
If 65 °C or higher is consistently required, and depending on the desired draw-off capacity, a hybrid system configuration may be more efficient. The Enevator Store then provides energy-efficient preheating of the water, while a high-efficiency gas-fired boiler, such as the BFC, or an electric boiler, such as the DRE Plus, reheats the water to the desired final temperature. This allows you to make optimal use of the heat pump for the majority of the heat demand, while ensuring sufficient capacity remains available for peak periods and higher temperature requirements.
In many projects, the Enevator Store as a preheater for gas or electric boilers is therefore an attractive solution when higher temperatures are required. Combining different technologies can result in a reliable and energy-efficient hot water system. The most suitable configuration depends on factors such as circulation losses, the hot water profile, pipe lengths, the desired temperature, the required capacity, and the available technical space. Proper sizing therefore remains essential.
Even small technical spaces offer opportunities
There is still a common misconception that a heat pump water heater only functions properly in a large utility room. In practice, this is not always the case.
Larger, well-ventilated spaces remain the ideal environment for a heat pump water heater. Especially when the temperature remains stable above 10°C, the heat pump can meet a large portion of the heat demand, and the highest efficiencies are achieved.
At the same time, the installations studied show that even smaller utility rooms can yield good results. Although the heat pump is more often supplemented by electric heating elements under less favorable conditions, its performance often remains significantly better than that of a traditional electric water heater.
This makes Enevator Store an attractive option for renovation projects and existing buildings where space is limited.
The Importance of Proper Sizing
The site visits once again underscore how important proper sizing is for optimal performance.
When the hot water demand is consistently higher than the available heat pump capacity, electric backup will need to kick in more often. As a result, the share of renewable heat decreases, and the system’s overall efficiency drops.
In systems that were well-tuned to the actual usage profile, the use of electric backup remained limited. This successfully combined a reliable hot water supply with high energy efficiency.
The results confirm that a successful heat pump water heater installation begins with a design based on the building’s actual hot water demand, rather than solely on storage volume or peak load.
A cooler mechanical room as an added benefit
Enevator Store not only produces energy-efficient hot water but also offers an added benefit in many situations.
Because the system extracts heat from the ambient air, it simultaneously creates a cooling effect in the mechanical room. This was perceived as a positive effect at several locations, especially during warmer periods.
In buildings where mechanical rooms are susceptible to rising temperatures, this can contribute to a more manageable system environment. Although energy savings and sustainable hot water production remain the most important benefits, users also frequently appreciated this cooling effect.
Key Conclusions
- A maximum storage temperature of 60°C ensures the highest heat pump contribution and limits the use of electric backup.
- Larger, well-ventilated utility rooms remain the ideal installation environment.
- Even smaller rooms with limited ventilation can deliver excellent performance and significant energy savings.
- Proper sizing is essential for optimal efficiency.
- The Enevator Store functions effectively both as a standalone heat pump water heater and as part of hybrid hot water systems.
- User satisfaction was remarkably high at all locations studied.
More possibilities for heat pump water heaters
The main conclusion? In practice, heat pump water heaters often prove to be applicable in more situations than initially assumed. Good design principles remain important, but the results show that even buildings with limited space or less favorable conditions can benefit from the advantages of a heat pump water heater. Even when the available technical space is limited, Enevator Store can achieve significant energy savings compared to traditional electric hot water solutions, without compromising comfort or hot water availability. Practical experience shows that successful implementation does not always depend on perfect conditions, but primarily on a well-designed system that matches the building’s hot water demand.
“The biggest surprise was not that Enevator Store performs optimally under ideal conditions, but that the system continues to deliver reliable results even under less-than-ideal conditions.”
Combined with sustainable energy generation, such as solar panels, Enevator Store also offers a smart way to convert surplus renewable electricity into usable heat. This makes the solution attractive for buildings seeking to become more sustainable and get more value out of locally generated energy.
After more than 195,000 operating hours across 17 installations, the conclusion is clear: Enevator Store combines energy savings, reliable performance, and a comfortable hot water supply in a single future-proof solution.