Best Practice Guide: Heat Pump Adoption for Schools

Reading Time: 3 minutes

As part of Warneford Consulting’s long advocacy of the features and benefits of adopting a ‘fabric first’ approach to and interconnecting with a route towards estates’ transitioning to Net Zero, in collaboration with long term decarbonisation experts, Green Net Zero, co-founder, James Smurthwaite, has produced this insightful blog on the subject. We hope you find it useful. 

“Transitioning from the use of existing gas boiler systems to heat pumps can significantly improve energy efficiency and reduce carbon emissions in school buildings. However, achieving optimal performance and return on investment (ROI) requires careful consideration of building fabric and heating system design. This guide outlines when schools should consider heat pumps, including key performance benchmarks for building insulation and guidance on hybrid and full heat pump scenarios.” James Smurthwaite, Green Net Zero  

 

Fabric First Proposal 

Empowering your school to make the most appropriate decision. 

Does your school building meet qualifying criteria? 

  • Does the building envelope meet minimum U-value standards? 
    • Minimum U-values are defined by building regulations for retrofit: 
      • Roof: 0.15 W/m²K 
      • Building envelope: 0.18 W/m²K
  • Do you have sufficient spare electrical capacity? 
    • A recommended minimum spare capacity of 20% of the total heating capacity is required for air source heat pump installation.
  • If not, do you have a plan to address any shortfalls within 5 years? 
    • Consider upgrades to electrical infrastructure, such as replacing life-expired key components, to ensure future readiness.
  • Do you have an estates strategy that draws upon quinquennial condition data for replacing life-expired key fabric and components? 
    • Regularly updating your estates strategy ensures timely upgrades and alignment with energy efficiency goals.
  • Do you have an estates decarbonisation strategy? 
    • Include installation of LED lighting and solar PV systems to provide additional electrical capacity and lower operational costs.
  • Do you know what level of additional electrical capacity is available from your District Network Operator (DNO)? 
    • Understanding DNO capacity is essential for planning future electrical upgrades. 


Understanding U-Values 

U-values measure the rate of heat transfer through building elements, with lower values indicating better insulation. Achieving suitable U-values is essential for heat pump efficiency, as these systems operate most effectively in well-insulated buildings. 

Recommended U-Values for Heat Pump Systems 

Building Element 

Minimum U-Value (W/m²K) 

Best Practice U-Value (W/m²K) 

Walls 

0.30 

0.18 

Pitched Roofs 

0.20 

0.12 

Flat Roofs 

0.25 

0.15 

Floors 

0.25 

0.15 

Windows & Doors 

1.60 

1.00 
  • Minimum U-Value: Suitable for hybrid systems where heat pumps are paired with gas boilers to maintain high flow temperatures (50-70°C). 
  • Best Practice U-Value: Recommended for full heat pump adoption, allowing low flow temperatures (35-50°C), maximising efficiency and ROI. 

 

When to Consider Heat Pumps

Hybrid Systems 

  • Building Characteristics: Older buildings with moderate insulation improvements that do not yet meet “best practice” U-values. 
  • System Design: Heat pumps provide the base load at low flow temperatures, with gas boilers used for peak demand. 
  • Advantages: 
    • Lower initial investment compared to a full heat pump system. 
    • Gradual decarbonisation while maintaining reliable heating. 
    • Energy security.

Full Heat Pump Systems 

  • Building Characteristics: Well-insulated buildings meeting or exceeding “best practice” U-values. 
  • System Design: Heat pumps supply 100% of heating needs, operating at low flow temperatures for maximum efficiency. 
  • Advantages: 
    • Significant carbon and energy cost reductions. 
    • Alignment with net-zero carbon goals.
       

Consideration of Electrical Capacity 

Installing heat pumps increases electricity demand, which may strain existing electrical infrastructure. Schools should assess spare electrical capacity and plan upgrades as needed.

 

Enhancing Electrical Capacity 

  • Implementation of LED Lighting:
    • Replacing traditional lighting with energy-efficient LED lights reduces overall electricity consumption, freeing capacity for heat pump operation.
  • Solar Photovoltaic (PV) Systems
    • Installing solar PV systems generates renewable energy on-site, lowering operational costs and supporting heat pump power needs. 
    • Excess energy can be stored or fed back into the grid, further enhancing financial and environmental benefits.
  • Assessing DNO Capacity: 
    • Contact your District Network Operator to determine available capacity for future electrical upgrades.

Steps for Schools to Prepare for Heat Pumps 

  • Conduct an Energy Audit (Stage 1 JTD): 
    • Assess current insulation levels and calculate U-values. 
    • Identify heat loss areas and prioritise upgrades. 
    • Evaluate spare electrical capacity and potential for on-site generation.
  • Upgrade Building Fabric: 
    • Insulate walls, roofs, and floors to meet or exceed “best practice” U-values. 
    • Replace or retrofit windows and doors with high-performance alternatives.
  • Evaluate Heating System Design: 
    • Consider hybrid systems for incremental progress. 
    • Plan for full heat pump adoption as part of long-term energy strategy.
  • Enhance Electrical Infrastructure: 
    • Upgrade electrical panels and wiring where necessary. 
    • Implement LED lighting and solar PV to increase capacity and reduce operational costs.
  • Seek Professional Guidance: 
    • Consult with energy and HVAC specialists to determine feasibility. 
    • Develop a phased implementation plan tailored to the school’s budget and goals.” 

If you want to discuss how a Fabric First approach can benefit your school estate, please don’t hesitate to get in touch with Tim Warneford at tim@warnefordconsulting.com