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We have all felt the impact of rising energy costs in recent years, and the education sector is no exception. In 2023/24, energy expenditure in UK schools reached a staggering £1.2 billion – doubling the sector’s energy spend in a mere five years.
These soaring costs are a major issue for schools, academies and local authorities whose budgets are already stretched thin. Yet, within this challenge lies significant opportunity for energy saving in schools. Our experience shows that the average school could be saving hundreds of thousands of pounds each year on their energy bill, all while fostering more comfortable environments and slashing their CO2 emissions.
Uncovering these savings is much more readily achievable, and inexpensive, than you might expect too - providing you know how to navigate some common pitfalls.
In this blog, we explore the challenges, risks, and opportunities in improving the energy performance of schools, and share how IES can help local authorities, schools, and DfE framework providers unlock significant savings. Helping to reduce both upfront capital (CapEx) and ongoing operational costs (OpEx).
In November 2021, the DfE updated its guidance to encompass a broader and more stringent range of design criteria. This update - and the accompanying ‘School Output Specification’ technical annex documents - introduced hard limits on Energy Use Intensity (EUI) and signalled a notable step-change in the industry’s approach to school design. This included substantial changes aimed at reducing operational energy demand, whilst still maintaining high levels of Indoor Environmental Quality (IEQ).
As with most building types, studies have shown that the operational performance of school buildings rarely matches design expectations, including those built under the Schools for the Future (BSF) and Priority School Building Programmes (PSBP). While it would be safe to assume that projects following the latest DfE guidelines will perform better, and at lower cost, than schools delivered under these earlier programmes, promised EUI targets are still not guaranteed by any means.
As of September 2024, only 24 projects have been built under the new guidance, meaning there is insufficient operational data to verify their in-use performance credentials. However, based on evidence that IES has seen to date, the trend of below-target performance within DfE schools looks set to persist, unless clients and design teams work together to avoid some common pitfalls; and doing so can offer substantial CapEx and OpEx savings.
There is a range of design and contractual causing DfE projects to fall short of their operational energy goals. These directly impact energy use in schools, resulting in higher-than-predicted operational costs and environmental footprints.
Clients need to share risk with their supply chain to achieve their objectives. Currently, there is no mandate in place to ensure EUI performance targets are achieved in use under DfE guidelines. This means that unless this is specifically included within contract documents, liability for operational energy performance tends to remains with the client, discouraging best practice where operational performance modelling is concerned.
Outdated modelling methods, based on simplistic compliance calculations and CIBSE loads assessments, are often used in place of more accurate, detailed HVAC modelling. This encourages frequent mis-sizing of building services, leading to Indoor Environmental Quality (IEQ) problems, inflated capital costs, and operational energy inefficiencies (particularly when concerning heat pumps). Limited availability of high-quality design stage predictive energy models also means that electrical grid connections are routinely sized based on ‘rule of thumb’ methods (e.g. BSRIA BG 84/2024). Whilst these methods ensure sufficient grid connection capacity, they often result in substantial additional costs for the client.
Schools may be less resilient to overheating risks than design-stage modelling suggests (though further data will be required to evidence this), leading to increased cooling requirements and costly retrofits down the line.
The DfE has limited resources to thoroughly evaluate the quality of design stage modelling. Whilst the technical documentation is clear on the need for models to ‘accurately calculate the predicted regulated and unregulated energy loads of the School’ it is rarely followed to the letter. Instead, thermal modelling is undertaken using basic modelling and compliance-driven methods and template data, resulting in design stage models which cannot accurately predict in-use performance.
A lack of funding and contractual liability perpetuates a “same again” mentality, which presents fewer risks to contractors and cost consultants, but passes the risk of increased capital and running costs onto the end client. Too often, in-use EUI targets are considered with a light touch as, beyond reputation value, there is a limited financial incentive for the contractor to achieve them. Similarly, facilities managers may not be financially incentivised to report under-performing assets if doing so runs the risk of suggesting culpability for under-performance.
If these risks aren’t properly managed, local authorities, schools and academies will end up wasting substantial amounts in both capital and operational energy costs that could quickly run into the hundreds of thousands - if not millions - over the course of a few short years.
Let’s take the example of an 11,000 sq.m secondary school to demonstrate our point:
If the in-use EUI is 20-60% above the design stage EUI (a very plausible scenario), the additional cost to run the building will be an additional ~£35,376– £106,128/yr.
Now let’s consider the electrical grid connections for that school. These are funded by the electricity bill payer, not the contractor, up to the cost of £1,720/kVA (most schools will fall below this limit). These costs are paid via an additional levy on their electricity bill over a 5-year period.
So, if the electrical grid connection for that school is sized at 800kVA, despite the MEP engineer indicating that a 550kVA connection would be sufficient (a very real scenario which IES observed on a recent project, where peak load on the grid connection to date has only been 398kVA), this decision will land the school with a bill of £250,000 - £375,000 to pay over a 5-year term (assuming an average cost for grid connections of £1,000–£1,500 / kVA).
Altogether, this would result in an avoidable overspend of £426,880 - £905,640 over the first 5 years of operation for this school.
Fortunately, these wasted costs can be avoided at minimal expense with the support of a trusted building performance expert.
To ensure successful energy saving in schools, contracts should include clauses to ensure the delivery of target EUIs in use, specifying the implementation of operational digital twin technology, based on building physics first principles, to evidence occupancy behaviour and building performance. Doing so will cascade liability through the supply chain, ensuring that best practice is encouraged.
Thermal modelling consultants should also work with architects to optimise pre-planning stage architectural design concepts. This will ensure that architectural designs are aligned with the requirement to deliver low EUI in operation, while ensuring that CapEx and programme overrun risks are reduced through early stage risk control.
Dynamic thermal modelling, which follows DfE guidance, should also be written into contracts and checked by a suitably qualified third party. This will ensure that EUI risks arising from the design stage model are appropriately managed, limiting the risk of HVAC oversizing and allowing for substantial cost reductions and performance gains in the process.
Once the building is operational, design stage models can be developed into digital twins and fed with live data, allowing in-use EUI to be verified and performance issues to be diagnosed . This will also enable ongoing performance monitoring and reporting, to prevent schools drifting into inefficient modes of use over time.
Our team has extensive experience supporting DfE projects from early design through to operation, helping schools unlock significant energy, carbon and cost savings. Our comprehensive services can support all of the above recommendations, and include:
Looking for support on your DfE project? Contact our team to discuss your requirements further.
