Installing a heat pump — especially an air to water system — is a smart investment for energy efficiency and sustainability. However, improper installation can significantly reduce its performance, lifespan, and ROI. In fact, studies show that over 30% of heat pump issues stem from poor installation practices.

This guide highlights the most common heat pump installation mistakes to avoid and how to ensure your system performs optimally from day one.

⚠️ Why Proper Installation Matters

Even the most advanced heat pump can underperform if installed incorrectly. Mistakes in sizing, placement, or commissioning can lead to:

• Higher energy bills

• Inconsistent heating or cooling

• Premature system wear

• Noise issues or leaks

• Voided warranties

Top 10 Heat Pump Installation Mistakes to Avoid

1. ❌ Wrong System Sizing

Problem: Oversized or undersized units lead to inefficiencies.
Fix: Always perform a proper heat loss/gain calculation to size the unit based on property specifics.

2. ❌ Poor Outdoor Unit Placement

Problem: Blocking airflow or placing units near noise-sensitive areas.
Fix: Install in an open area with at least 30–50 cm clearance and good airflow. Avoid wall-mounted units without vibration pads.

3. ❌ Inadequate Home Insulation

Problem: Even a perfectly installed heat pump won’t perform well in a poorly insulated home.
Fix: Upgrade insulation, windows, and seals before installing the system.

4. ❌ Using Old Radiators or Pipework

Problem: Traditional high-temp radiators may not work efficiently with low-flow temp systems.
Fix: Install low-temperature radiators or underfloor heating systems.

5. ❌ No Buffer or Hot Water Tank

Problem: Without thermal storage, short-cycling can occur, reducing efficiency and lifespan.
Fix: Add a properly sized buffer tank or hot water cylinder for stable operation.

6. ❌ Incorrect Flow Temperature Settings

Problem: Setting the heat pump to run at too high a temperature (e.g., 65°C+) ruins its efficiency.
Fix: Set flow temp between 35°C–50°C, and balance with appropriate emitters.

7. ❌ Skipping System Commissioning

Problem: Many installers forget or rush the final commissioning process.
Fix: Ensure full testing, flushing, pressure checks, and controller programming are completed and documented.

8. ❌ Lack of Weather Compensation

Problem: Systems that don’t adjust based on outside temperature may overheat or waste energy.
Fix: Use smart controls or weather compensation for adaptive efficiency.

9. ❌ No Electrical System Upgrade

Problem: Underpowered or outdated fuse boxes can lead to safety hazards.
Fix: Upgrade electrical infrastructure and install a dedicated heat pump circuit with RCD protection.

10. ❌ Not Hiring a Certified Installer

Problem: Non-certified installers may void warranties or miss key requirements for incentives.
Fix: Always hire MCS-certified (UK), F-Gas certified (EU), or NATE-certified (US) professionals.

✅ Pro Tips for Homeowners

• Ask for a detailed site survey report

• Check for past project references

• Get multiple quotes, but don’t just go for the cheapest

• Demand a full handover with commissioning certificate

Post-Installation Checklist

• System runs quietly and efficiently

• Outdoor unit has proper airflow clearance

• Thermostats and sensors calibrated

• No leaks or strange noises

• All documentation, warranties, and rebate forms received

Final Thoughts

An air to water heat pump can reduce your heating bills by up to 60%, but only if installed correctly. Avoiding these common mistakes ensures you’ll enjoy optimal performance, low maintenance, and long-term savings.

Remember: “A good heat pump is only as good as its installation.”