MRes Student – University College London
On February 21 2018, LoLo students were offered the chance to visit one of Melius Homes’ live construction sites in the city of Nottingham. Comprised of ten properties, the site is a pilot study aiming to improve the energy-efficiency of older homes by adopting the EnergieSprong approach to retrofitting existing homes, following the initiatives great success in The Netherlands. The company’s principal aim is to deliver low energy homes by wrapping existing dwellings in pre-fabricated wall and roof panels, produced off-site at the Melius Homes factory. EnergieSprong first introduced this pre-fabrication step to reduce the occurrence of construction faults and improve the finish of external and internal fittings. The great success achieved with the original parent project has led to a thousand homes a year now receiving the energy-efficient makeover in The Netherlands.
The site in Nottingham offers a unique opportunity to really gauge the effectiveness of this process, as the ten Nottingham City Council homes sit amongst two properties of the same build, both of which have been bought under right-to-buy mortgages and therefore did not receive the retrofit. Thus, this site is able to capture the benefits offered by the retrofit comparatively, not only on aesthetics, but on also how sustainable the new features will be in the future compared to the older design on the privately rented properties.
The site is situated on an unassuming street about a ten-minute walk from Nottingham city centre, and so the homes are located in a desirable spot near a range of amenities (including a local café, which was the chosen spot for lunch). Upon our arrival, David Adams, chair of the LoLo advisory board and technical director of Melius Homes, greeted us. The first task scheduled for the day was a tour of the site, which is a live site still undergoing construction work, although the project is in its final stages. At first glance, the homes are rather striking and it is immediately obvious which dwellings have received the high-tech makeover. The properties are best accessed via the road which leads to the rear of the homes, where sits a Juliet balcony set against an array of pink and purple backdrops. The overall look is pleasing to the eye and this is one of the aims of the EnergieSprong approach: as well as delivering energy-efficient homes the design is also meant to be visibly attractive to both occupants and neighbours. Compared with the privately rented homes, situated adjacent to and in-between the retrofitted dwellings, the properties appear brighter due to the newer layer of cladding and the spectrum of pink to purple doorframes and balcony features.
The homes had been kitted out with a thermally insulated roof cassette with built-in solar PV panels, wall envelope insulation, double-glazing and we looked inside the Energy Centre; which houses the two heat pumps, hot water cylinder, the PV co-trip panels and in future, the batteries. The very end house is currently uninhabited and is being used as a central hub for the few members of the construction team still on site (and a tea and coffee stop for the day’s rather large LoLo arrival), so we did get the chance to see inside one of the properties.
The second half of the day was a little more interactive and included different groups carrying out various activities. Some got the chance to carry out a focus group and sit down with two residents from the retrofitted properties, whilst others took the opportunity to use thermographic cameras. The third group performed back-of-the-envelope calculations to get down to the ‘nitty-gritty’ of the true savings on offer through the retrofits. The day was rounded up with a feedback session where the different groups reported on what they had found during their individual tasks.
The thermal imaging cameras provided convincing results of the retrofits’ effectiveness, with over a two-degree difference between the heat emitted from the retrofitted house versus the non-retrofitted, privately owned property (6.1°C vs. 8.2°C, respectively). The cameras even identified areas for improvements, and the students who opted to do this task found potentially damaged sealing around the Juliet balcony windows on all of the properties, which may have been a problem arising at the manufacturing stage.
Back-of-the-envelope calculations also gave some impressive evidence for the financial savings on offer through the retrofit and use of the ground source heat pump (GSHP). The group determined that the makeover reduced the mean demand for space heating by 5.8kW, and suggested that over a 30 to 40 year period, the retrofit would save around £75,000 per home when considering the counterfactual of wind power driven resistance heating to 20°C throughput. This figure was surprisingly close to the upfront cost of the refurb, which David revealed earlier in the day, was between £65K and £75K per dwelling.
Those who got the chance to speak to the residents reported that despite some disruption, they were overall extremely satisfied with the outcome of the project. The residents were convinced the retrofit had improved their living conditions, and it was good to finally see some of the energy-efficient features we meticulously read and write about in practice and making a difference to people’s lives.
On behalf of both students and staff from London and Loughborough, I would like to thank David and the rest of the team at Melius Homes and Nottingham City Council for inviting the LoLo team to the site and we wish you the best of luck with the future expansion of the EnergieSprong approach to retrofitting by Melius Homes!
A large group of students attended the day. Melius Homes kindly went out of their way and gave us a mug each to keep us all warm and watered!