MODULE 7. Retrofitting with Heat Pumps

Retrofitting buildings with heat pumps is one of the most effective strategies for achieving the European Union’s 2050 climate-neutrality target. Around 75% of buildings across Europe are energy-inefficient, and most still depend on fossil fuel-based systems such as gas or oil boilers[1]. Retrofitting is far more complex than simply replacing a boiler. Most heating systems were originally designed for high-temperature water distribution (typically 70–80 °C) that is incompatible with the low-temperature operation (30–50 °C) at which modern heat pumps achieve their highest efficiency[2]. Successful integration therefore requires a comprehensive approach: upgrading the thermal envelope, adapting emitters and hydronic circuits, ensuring electrical compatibility, and training users to operate systems designed for steady, low-temperature comfort.

To meet climate neutrality goals by 2050, a large-scale transition to heat pump technologies is necessary — not only in new constructions, but critically in the existing building stock.

Module 7 focuses on the technical aspects of integrating heat pumps into existing systems. While Modules 1–6 covered core thermodynamics, cycle components, HVAC design, and energy auditing, this module builds on that foundation with a practical, retrofit-specific approach.

In this module, learners will explore the main technical challenges and strategies associated with:

• operating hydronic systems at low water temperatures,
• modifying and balancing existing distribution circuits,
• validating system performance through commissioning, and
• ensuring electrical and user-interface compatibility.

Real-world case studies, analytical tools, and system diagrams will illustrate how legacy buildings can be effectively adapted to a clean-energy future.

🎯 Learning Outcomes

By the end of this module, learners will be able to:

1. Explain why low-temperature systems are crucial for efficient heat pump operation
2. Analyze existing hydronic systems and identify retrofit needs
3. Adapt piping layouts, flow dynamics, and emitters to fit HP requirements
4. Ensure electrical compatibility and implement grid-smart operation
5. Apply commissioning protocols specific to retrofit environments
6. Assess real-life retrofit projects for technical and economic feasibility