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Rare DEC to EPC conversion at London's oldest school

Clerkenwell Parochial School has a history stretching back over 300 years and witnessed live-readings by none other than local literary icon Charles Dickens

The former Clerkenwell Parochial School
Exterior of 25 Amwell Street

Building History

Founded in 1699 as one of London's very first Charity Schools and moving to the site in Amwell street in 1828, it is these premises which are believed to be the oldest state-school building in continuous use in London. Its a beautifully presented late-Georgian construction and is unsurprisingly Grade II listed. In the 1860's local wordsmith Charles Dickens used rooms in the school for 'penny-readings' of his work and this was commemorated in the house names in the School - Marley, Nancy, Dorrit and Twist.

Unbelievably for central London, dwindling pupil numbers led to its closure in 2021 but the building remained in educational use until the present day. It's now available to lease (via DWD) and we were called in to survey for a new EPC as the existing DEC was no longer appropriate.

Detail view of school entrance

What is a DEC - Display Energy Certificate?

Display Energy Certificates are similar in many ways to the more frequently found Energy Performance Certificate (EPC) they produce the same familiar rating chart and display the buildings energy use and carbon emissions. However unlike regular EPCs they are specifically for use in buildings belonging to a Public Authority - typically Hospitals, Council Buildings and as in this instance, Schools. They also must be

  • a minimum of 250 square meters

  • frequently visited by the public

the DEC must be displayed in a prominent position and unlike a normal EPC they must be renewed annually. As this building is coming out of public use its DEC had to be replaced with an EPC, a relatively rare occurence.

Example of a Display Energy Certificate
The existing DEC for the School

At first glance the certificate above appears almost interchangeable with a typical commerical EPC - however the methodology used to devise them is very different indeed.

What's the difference between an EPC and a DEC?

An EPC looks at a buildings structure and services and assess its potential energy usage whereas a DEC is devised primarily from the previous 12 months utility data (gathered from bills) and as such illustrates how much energy that building is actually using.

A good illustration of this would be to imagine something like a datacentre, an EPC assessment may show a very positive score if the building's construction, lighting and HVAC system were all efficient. Now if the same building was in public ownership by say the NHS and received (rather inexplicably) large numbers of the public a DEC would be required and it would take into account the huge electicity usage of all the IT hardware within the building and it may achieve a relatively poor score.

EPC results

We're happy to say that despite being nearly 200 years old the provisional result of our EPC assessment is a band D for the building and it can now lawfully continue into a new life and remain a boon to the local area. We also conducted a seperate EPC for an adjoining modern building which had been part of the same school estate, built in the early 2000's it unsurprisingly scored a B. Interested parties should contact Tory at DWD for particulars and viewings.


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