Stiebel Eltron WPL A2W Premium
Heat pump water heaters (HPWHs) are an efficient, electrified alternative to natural gas and electric resistance water heating in commercial and multifamily buildings. By extracting heat from ambient air and transferring it to water through a refrigeration cycle, HPWHs can achieve coefficients of performance (COP) two to four times greater than traditional electric resistance heaters. This efficiency translates to lower operating costs, reduced energy use, and significant greenhouse gas (GHG) reductions.
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Stiebel Eltron WPL A2W Premium
Premium German engineered system emphasizing quiet operation, reliability, and integrated controls. Available with factory matched tanks and accessories for turnkey residential and light commercial installations.
Hub Highlights:
- Tested COP 2.6–3.4 (at 47°F / 105°F)
- 14.8 kW heating capacity
- R454B
- -4 F (-20 C)
- 149 F (65 C)
Last Edited on: November 2023
| Model Number | WPL 25 |
| Product Type | Monoblock air-to-water heat pump |
| Application | Space heating and cooling, domestic hot water with accessory tank |
| Heating Capacity | 50,400 BTU/h full load |
| Heating Capacity (kW) | 14.8 kW |
| Cooling Capacity | 49,080 BTU/h |
| Cooling Capacity (kW) | 14.4 kW |
| Published Heating COP | 4.24 at A47 W105 (max capacity) |
| Published Cooling EER | 16.83 IPLV |
| Seasonal COP (SCOP) | Cold Climate Efficiency COP 2.77 |
| Minimum Operating Ambient Temperature | -4 F (-20 C) |
| Maximum Operating Ambient Temperature | 104 F (40 C) |
| Maximum Supply Water Temperature | 149 F (65 C) |
| Minimum Supply Water Temperature | 59 F (15 C) |
| Refrigerant | R454B |
| Refrigerant GWP | 466 |
| Electrical Supply | 220–240 V single phase |
| Compressor Type | Variable speed inverter |
| Capacity Modulation | Wide inverter modulation |
| Integrated Circulation Pump | Yes |
| Control System | Integrated controller |
| Sound Level | 66 dBA max, 54 dBA silent mode |
| Certifications | Not available |
| Dimensions (Outdoor Unit) | 58.6 x 23.4 x 41.1 inches |
| Weight (Outdoor Unit) | 386 lb |
| Country of Manufacture | Germany |
| Intended Distribution Systems | Radiant floors and fan coils |
| Climate Suitability Category | Cold Climate Capable |
|
Reference Outdoor Temperature (°C)
|
8.3 |
|
Reference Entering Water Temperature (°C)
|
40.5 |
|
COP – Speed 1
|
3.44 |
|
COP – Speed 2
|
3.23 |
|
COP – Speed 3
|
3.02 |
|
COP – Speed 4
|
2.81 |
|
COP – Speed 5
|
2.61 |
Data Collection
Observations relevant to installation, operation, and maintenance based on laboratory evaluation and product documentation review.
Installation
System Configuration
Monoblock
Installation
Refrigerant Line Installation Required
No
Installation
Integrated Circulation Pump
Yes
Installation
Unit Weight
386 lb (heaviest tested)
Installation
Refrigerant Flammability Class
A2L (R454B)
Installation
Electrical Supply
220–240 V 1-phase
Controls & Communication
Communication Interface Used in Testing
Modbus — functional
Controls & Communication
Control Interface Type
Integrated controller with display panel
Controls & Communication
Remote Monitoring / App
ISG web interface (optional)
Controls & Communication
BMS Integration
Modbus; BACnet via gateway
Operation
Sound Level
54–66 dBA (silent mode available)
Operation
Min Operating Ambient Temperature
-20°C (-4°F)
Operation
Max Supply Water Temperature
65°C (149°F)
Operation
Compressor Modulation
Variable speed
Operation
Suitable Distribution Systems
Radiant floors, fan coils
Maintenance & Support
Country of Manufacture
Germany
Maintenance & Support
Diagnostic / Fault Reporting
Detailed fault codes with descriptions
Maintenance & Support
Refrigerant GWP
466
Maintenance & Support
Lab Testing Observations
Unit operated as expected; higher inrush current noted