Scottish Schools Mind the Gap

by Jay Fox

The headline news out of Scotland is that all new built homes will be required to meet a Scottish equivalent of the Passive House standard as of January 2025. This tectonic shift in policy reflects Scotland’s determination to cut emissions and meet its climate goals while also reducing fuel poverty among those living in new social housing.

However, years before Scotland began to seriously consider this requirement for newly built homes, the Scotland Futures Trust (SFT)—a non-department company owned by the Scottish Government that works with the public and private sectors to finance and support infrastructure projects within Scotland—had made a similarly dramatic, albeit more complex, shift in policy. This policy applies to new schools and was instituted after research conducted by Edinburgh City Council’s sustainability division showed that some relatively new schools were performing as poorly as schools from the Victorian era, or indeed even worse. Finalized in March 2020 and known as the Learning Estate Investment Programme (LEIP), the initiative incentivizes reductions in energy consumption and emissions for newly built schools while also improving indoor air quality (IAQ) for students and teachers. It realizes each of these objectives by tacitly encouraging schools to be built to Passive House standards.

Identifying a Gap in Performance and Air Quality

A persistent scourge of the construction industry, the performance gap— defined as the disparity between the anticipated energy use of a building as modeled and the actual use once it is built— arises due to a multitude of factors that can be difficult to resolve. The dominant reasons for the gap are uncertainty of specifications during modeling, poor operational practices, and unanticipated occupant behavior, according to a 2016 paper published in Frontiers in Mechanical Engineering. The paper estimates that the three issues have an estimated effect on energy use ranging from 20-60, 15-80, and 10-80%, respectively (see Table 1). Other contributing factors identified in the paper include unanticipated changes to design made during construction, poor commissioning, and substandard construction practices.

In addition to diminished comfort, the performance gap can lead to more emissions, which undercut climate goals, and higher utility bills. In public buildings like schools—where utility bills are covered by taxpayers—large, unexpected costs can also stress budgets and detract from other public services.

In schools, the disparities in energy use can be significant. Prior to the COVID-19 pandemic and the war in Ukraine, the average secondary school in England spent approximately £90,000 on energy. However, several new secondary schools in Scotland that had been built only within the last decade and were supposed to be significantly less expensive to operate were costing upwards of £200,000 per year to run. According to Architype Associate Director, Architect, and Certified Passivhaus Designer Ann-Marie Fallon, these were not hastily constructed schools built on a shoestring budget; they were designed to be more efficient and sustainable than the average school.

To get a better understanding of why the performance gap was so wide, Architype, a UK-based architecture firm specializing in Passive House design, performed post-occupancy monitoring between 2017 and 2020 for three of Edinburgh’s five most expensive secondary schools to operate. What they found was that there were issues with form, massing, and the MEP not being commissioned correctly, as well as clashes between initial designs and finalized products in terms of user experience and comfort. As one example, these were simple things “like blinds clashing with windows that were planned to be opened by the M&E engineer on an orientation with challenging glare issues. But then the architect comes along and—driven by other compliance requirements—puts blinds in or puts a restrictor on,” Fallon explains. “Suddenly that window doesn’t open the way the energy model said it would.” As teams progress through the design process, the holistic approach to resolving all design parameters can be lost, which is then further compounded once a building is in use—precisely when most architects step away from the project.

Similar problems were discovered during a comparative study conducted by University College London and Architype from 2016 that involved three tiers of sustainable primary schools across the UK. The first tier was composed of naturally ventilated schools made with natural materials, the second tier included mechanically ventilated schools that achieved a score of excellent following the British Research Establishment Environmental Assessment Method (BREEAM), and the final tier consisted of schools that had received certification by the Passive House Institute. The study also included an uninsulated school that had been built in the 1970s.

Like the secondary schools, the non-Passive House primary schools were more expensive to run. Another thing that became crystal clear was that the non-passive schools were not properly ventilated. The first and second tier schools may have performed better than the school from the 1970s throughout the seasons, but only the Passive House schools could consistently keep CO2 levels below the recommended average of 1000 ppm throughout the year.

As the situation stood, taxpayers were footing the bill for the construction of schools that were underperforming, uncomfortable, poorly ventilated, wasteful, and expensive. What they needed was a performance-based model capable of providing better thermal comfort and better ventilation while driving down emissions and operational costs. Moreover, because schools are public buildings that may experience decades or even centuries of use, obtaining a quick monetary return on the investment was not a priority.

“Because buildings fail so badly, there needed to be a robust response to demonstrate quality,” Fallon says.

Scotland Steps Up

Which brings us back to the SFT. As SFT was deliberating on what steps should be taken to improve the design and construction of schools to achieve higher levels of environmental performance, energy efficiency, and IAQ, several representatives of the SFT met with Architype Managing Director Jonathan Hines, who described the success that Architype had seen with Passive House construction. When he told them that Passive House standards could dramatically increase building efficiency and narrow the performance gap in schools, he says the response was one of incredulity. “‘It all sounds too good to be true; we can’t really believe that it will work as you’re saying’,” he recalls them saying. However, within twenty minutes of visiting a Passive House school on which Architype had worked, they were sold.

What they were sold on was not just the benefits of Passive House construction or its ability to significantly reduce energy consumption, but the fact that it is a performance-based standard that has an intrinsic level of quality control. What you model is more or less what you get—not just today but for decades. Given the way the funding structure was ultimately set up by LEIP, this is vital, because the only way to receive full funding is to satisfy multiple outcomes categories, one of which is energy consumption as measured by kWh/m²/yr (see Table 2) over the course of 25 years.

“If a local authority wants to build a new school,” Hines explains, “they secure the approval from Scottish Government for funding. They have to put the capital up front, so they borrow to build it, and the Scottish Government pays them the money back over 25 years as a revenue payment.” That payment is tied to achieving different levels of energy metrics, as described in Table 2. If they receive a grade of A, they get 100% funding. If they receive an E, they get 0%.

While this policy does not require buildings to obtain Passive House certification, not employing Passive House methodologies becomes a significant risk due to LEIP’s performance-based funding mechanism. “The evolution of how Passive House fits into all of this—bad air quality, poorly designed buildings, catastrophic failures—is that it had an evidencable, benchmarkable trail through it to account for quality and decision-making,” says Fallon.

Adoption has been quick, and the city of Perth had the honor of becoming home to the first Passive House primary school in Scotland when construction of Riverside Primary was completed in June 2023. Designed by Architype and built by Robertson Construction, the approximately 4200-m² school can accommodate 500 pupils and a nursery for 82 children. While the school is currently an outlier, change is happening at a breakneck pace. As of early 2024, Fallon says that numerous firms are now building schools to Passive House standards and that there are approximately 30 Passive House schools in the pipeline.