Nottingham City Homes has pioneered Energiesprong revolutionary whole house retrofit in the UK, transforming 144 ‘hard to heat’ socially rented homes into warmer, more desirable places to live, tackling both fuel poverty and climate change.

The initial ten-home pilot project in 2017, designed by Studio Partington and delivered by Melius Homes, was the first in the UK to pilot net-zero retrofits using the Energiesprong approach, which has radically upgraded the energy efficiency of thousands of homes in the Netherlands. In 2021, the pilot scheme was chosen as one of 17 exemplary international projects for UKGBC’s Build Better Now virtual exhibition as part of COP26.

The pilot scheme comprised ten homes (a mix of terraced three-storey houses and bungalows) in Sneinton on the edge of the city centre. While the homes were well located and had an established community, they were cold, draughty homes with an inefficient design. The houses were particularly inefficient with an unheated garage under the living room and an undercroft below the kitchen.

The solution was a tenant-focused, highly efficient whole house retrofit delivering super insulated, low maintenance near ‘net zero operational energy’ homes. The retrofit has also transformed the neighbourhood with increased passive surveillance from converted garages and new first floor Juliet balconies as well as brighter finishes to courtyards.

Melius Homes were procured to deliver a performance outcome including 1500kwh net import, a maximum tenant cost of £330 p/a (2018 tariffs) and guaranteed comfort for tenants. Studio Partington worked closely with tenants in developing the design brief which enabled additional items that make a difference to tenants’ lives, such as light tubes making stairs brighter, outside taps for watering plants and a doorbell, to be provided.

Prefabricated off-site, wall panels arrived in ‘full storey heights’ complete with ample insulation, double glazed windows and a durable board finish, ready to crane into place. Tenants were able to remain in residence throughout the retrofit, which was completed in one week.

Following the pilot phase, additional funding was secured to continue developing the Energiesprong concept in Nottingham City Homes across the city, resulting in Melius Homes developing their own closed panel timber frame factory in Nottingham. Three different M&E approaches have been trialled, including a full communal energy system with private wire electricity and communal heating, communal ground source with individual heat pumps and batteries, and in the current scheme, individual air source heat pumps with battery storage. The final phase of homes was completed August 2023, with 144 properties fully transformed and a further 65 properties receiving renewables, reroofing and wall panel enabling works. A recent survey found that all tenants said they were comfortable or very comfortable in their new homes.

In 2018 the Climate Change Committee reported to parliament that the Nottingham retrofit “demonstrated the role that energy performance contracting techniques can play in driving high quality 'as-built' performance.”

The pilot retrofit has also won several awards:

• UK Housing Awards, 2018 ‘Innovation of the Year’

• Shift Awards, 2018 ‘Sustainable Retrofit Project of the Year’

• The Sunday Times British Homes Awards, 2019 ‘Housing Crisis Solution’

Read more in this project PDF and CIBSE Journal article (June 2018).