The UK has a problem; rather a large one. The Climate Change Act 2008 commits the UK to reduce carbon emissions by 80% from a 1990 baseline by 2050. In 2016 the biggest single consumer of energy was transport at 40%, but domestic use and the service sector together accounted for 44% of the energy used, the vast majority of that for buildings.

To meet our target we have to dramatically reduce energy consumption in buildings, and that is hard because we have an old building stock. 17% of homes were built before 1919, and over 80% of the homes we will be using in 2050 have already been built. As a nation we like old buildings and it seems very unlikely we will demolish and replace on a large scale.

We need to shift a very large number of buildings to a very high standard of energy efficiency. The UK Green Building Council estimates that we will need to retrofit 25 million homes.

Last week I visited a project in Nottingham that shows one way we could do this with a clever combination of technology and business model.

Technology for retrofitting

In 2009 I was involved in setting up the Retrofit for the Future programme at Innovate UK. This demonstrated that it was technically possible to take older buildings and bring them up to the required energy efficiency standard. Over 100 homes of many different construction types were refurbished. A quarter achieved over 50% reduction in energy use, and a few reached 80%. Several reports were produced for industry on what worked and what did not work in retrofitting.

So far so good, but the costs needed to come down a lot, the disruption had to be reduced and the speed of retrofitting dramatically increased. Trying to tackle that problem led to the Scaling Up Retrofit programme in 2013. One of the intriguing products that came out of that is the Q-Bot. A small robot that can crawl under a suspended floor spraying insulation foam. Quicker and less disruptive than lifting the floorboards, it has been successfully tested in the London Borough of Camden.

We are getting better at solving the technical problems of retrofitting older buildings, but it still isn’t happening fast enough. So I was delighted last week to visit the REMOUrban project in Nottingham and see real progress in making large scale retrofit commercially and socially viable.

REMOUrban Project – Nottingham

REMOUrban is an EU project on the regeneration and transformation of cities with a particular focus on energy efficiency and smart mobility. Nottingham is one of three ‘lighthouse’ cities where various approaches are being trialled. The project is hosted by Nottingham Trent University. The part of the project I saw was the refurbishment of older properties to extend their life, make them more comfortable and to reduce environmental impact and energy costs. The test site was a terrace and some bungalows owned by Nottingham City Homes that had very poor energy efficiency.

The technical solution was based on the Energiesprong approach that offers a one week retrofit, without the occupants having to move out, a 30-year warranty on internal comfort, all paid for by savings in energy consumption. Refurbishment was carried out by Melius Homes using external insulation panels, roof integrated PV and a ground source heat pump using 150m deep boreholes. This is the first Energiesprong project outside the Netherlands.

Technology is not the problem – novel procurement is the solution

The technical retrofit was impressive, but used well established techniques. The really exciting part of the project was the way in which it was financed and the relationship between customer and supplier.

The problem with retrofitting is not usually technical, it is:

  • Economic – how will retrofit be funded? Especially where there are split incentives, the landlord incurs the costs and the tenant derives the benefit.
  • Social – how do we persuade building users to accept high up-front costs and disruption for a long-term benefit?

Nottingham City Homes solved the problem with an unusual procurement that focused on the desired outcome and a guaranteed performance, rather than a design and materials specification to bid against. This Competitive Dialogue process allowed co-development of a solution between Melius and NCH with full engagement of the tenants in designing refurbishment that would meet their needs.

Melius are guaranteeing the energy performance of the refurbished homes for 30 years. It is in their interest to develop a robust design and plan at the beginning, in collaboration with the customer and users. The outcome based, and face-to-face procurement allows a proper evaluation of the options and costs. Being confident that the costs of a project can be met from energy savings means that more properties can be refurbished to high levels of performance and comfort, instead of having to demolish and rebuild.

It sounds simple, but it needed Nottingham City Council and their partners to take some real risks and push for what is still an unusual form of procurement. One that focuses more on finding the right solution and less on pure price.

Need to drive costs down

Are we there yet? Not quite. This is a prototype project and costs are still too high. But Melius calculate that a further 30% – 40% reduction in costs would make this approach commercially viable for retrofit. Increasing scale, more off-site manufacturing, and the use of construction techniques that avoid scaffolding, can deliver those savings. The next stage is to get funding to allow 200 homes to be refurbished; a key step in the scale-up journey to a cost-effective solution for domestic energy retrofit.

Nottingham have taken a major step forward. Other cities need to join in. The more these methods are trialled, the quicker we will have a solution for the 25 million homes we need to upgrade.


A Scaleable Approach to Improving Energy Efficiency in Buildings
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