Britain currently has 11 Passivhaus certified schools. A further 12 are under construction, including three in Edinburgh and four in Wales. The first of them were certified in 2011, and among them was Montgomery Primary School in Exeter.
Exeter, if you remember, is the city council that mandated that all new council buildings need to meet Passivhaus standard. As a result local builders have skilled up, and the price of building them has come down.
What makes Montgomery Primary School stand out is that it is the first school in Europe that is designed to be zero carbon in use. It does this by making the most efficient building possible, with levels of insulation and efficiency that actually surpass the Passivhaus requirements. It’s energy needs are 45% lower than a normal school of its size, making it able to meet all of its energy requirements, over the course of the year, through the on-site solar PV.
The school is so well insulated that it is primarily heated by its 450 students. “Montgomery Primary School is essentially an unheated building” says professor David Coley, one of the certifiers. “It isn’t a sealed box, as the comfort of the users is paramount; however the heat in the air leaving the building through ventilation channels is harvested and used to warm the fresh air coming in. There is some heat loss, but this is made up for by the occupation of the building by the heat from the pupils and staff.”
If it gets cold, especially on a Monday morning in winter, there’s an electric heating system that can boost the temperature through the ventilation system. It has to be manually activated and runs for 15 minutes as a time, so it’s only there if it’s needed.
Of course, how people live and work in the building matters too. There are lobbies, and a limited number of entrances, but you’re still depending on people closing the doors. The school runs energy workshops with staff and students to try and encourage good practice, and the builders monitored the school’s energy use for several years after it opened to see how it was performing.
There’s a lot more detail from Building magazine – including the use of pre-fabricated elements, the fact that it was a Passivhaus built by a major contractor (BAM), and how it was done at speed and on budget. The important thing for most of us is that it is quite possible to build schools to this standard, reducing costs every year for strained school budgets, and providing excellent learning environments for children. When you look at Montgomery Primary School and what it cost, there’s really no reason why we couldn’t build all schools to be zero carbon if we chose to do so.