Many homeowners have experienced the frustration of noisy heating pipes. What should be a gentle hum of circulating water often becomes an intrusive disturbance, particularly during quiet nights. As underfloor heating gains popularity for its comfort, the choice between copper and plastic piping emerges as a critical decision affecting both performance and tranquility.

Selecting piping materials requires careful consideration of flow rates, velocity, noise levels, and heat dissipation. Initial designs from NuHeat recommended 35mm copper pipes for high-flow circuits and 28mm copper for low-flow applications, while WUNDA remained non-specific about pipe specifications. This raises an important question: Is Hep2O plastic piping suitable for underfloor heating return circuits?

NuHeat's design specifies a maximum flow rate of 22.8 L/min, resulting in a velocity of 0.46m/s through 35mm copper pipes (32.6mm internal diameter). When using the largest Hep2O pipes (28mm outer diameter, 22.7mm internal diameter), the velocity nearly doubles to 0.94m/s. This significant increase prompts concerns about potential noise generation.

Alternative "one-to-one" layouts suggested by experts reduce maximum flow to 10.5L/min, maintaining velocity at 0.45m/s. However, WUNDA's design with 20.3L/min flow would again approach 0.9m/s velocity in plastic pipes. Precise calculations of flow and velocity are therefore essential to prevent acoustic disturbances.

• Thermal Conductivity: Copper's superior heat transfer means more warmth dissipates into surrounding structures. While this may contribute to room heating, it reduces system efficiency and increases energy consumption. Plastic pipes offer better insulation, minimizing heat loss.
• Noise Generation: High velocity remains the primary noise contributor. Copper's rigidity makes it more susceptible to water hammer and resonance effects. Hep2O's flexibility helps absorb hydraulic shocks, reducing acoustic transmission.
• Installation: Copper requires skilled welding, increasing labor costs and complexity. Hep2O's push-fit connections enable faster, simpler installation.
• Durability: Copper may corrode over time, while plastic materials demonstrate excellent corrosion resistance and longevity.
• Cost: Copper piping typically carries a higher price tag than plastic alternatives, impacting overall system costs.

• Implementing simplified "one-to-one" pipe layouts to minimize branches and flow rates
• Selecting appropriate pipe diameters based on flow requirements
• Installing vibration dampers at pipe supports and connections
• Maintaining stable water temperatures to prevent pipe expansion noises
• Conducting regular maintenance to remove air pockets and check fittings

Thermal calculations reveal that 22.8 L/min flow with a 5°C temperature differential delivers 8kW output. For heat pumps rated at 11.2kW, either increased flow or higher temperature differentials (7°C) become necessary. WUNDA's 20.3L/min design may prove excessive unless heating only specific zones. System design must therefore balance power requirements with hydraulic parameters.

Both copper and Hep2O present distinct advantages. Copper excels in heat transfer but may generate more noise and require complex installation. Plastic alternatives offer quieter operation, easier installation, and cost benefits. The final selection should reflect individual priorities regarding acoustics, efficiency, and budget. Regardless of material choice, proper hydraulic design remains paramount for creating a comfortable, high-performing underfloor heating system where warmth and silence coexist harmoniously.