Get comfortable with prioritisation. Thousands of homes in any given place will need retrofitting, so every project is an exercise in prioritisation.

How do we do this? The answer is to create a strong methodology at the start to give structure and make it clear to everyone why those decisions were made. At Nottingham, we created a fuel poverty index. The highest weighting went to areas with a higher proportion of residents vulnerable to fuel poverty. This created a route map around the city which helped Nottingham secure internal budgets and helped explain to stakeholders – including tenants – where their properties stood in the whole retrofit programme and why.

More recently, NCH schemes have focussed on whole-house approaches which brings in other factors such as:

• Number of homes owned by the local authority vs. number of privately owned ‘right to buy’ homes, and the impact of this on the efficiency of retrofits at scale.
• Budgets already allocated; so, for instance, where traditional roof maintenance is already planned for a group of properties, it may make good financial and resource sense to bring those properties forward in one or more stages of a retrofit programme.
• Complexity of delivery caused by the original build spec; some properties have been put back in the programme because we don’t yet have the solutions to retrofit them well.

What has Destination Zero taught us? There will be pros and cons to different project options. In fact, there might not be such a thing as a perfect project! The most important thing is to ensure that the opportunity is taken to maximise learning as most lessons are transferrable.

Know your archetypes. Each UK housing type needs a different approach to retrofit. Understand your project’s housing archetypes before setting out on a tender exercise, and you will be able to structure procurement in a way that attracts best prices and maximum grant and minimises risk.

Gathering this data is an example of the early spadework that pays off in the long term. If it’s done well, you can create a plan for each house that provides:

• a sound basis for project planning and costing.
• the information needed for live testing and adjusting for specific problems such as thermal bridging.
• a list of every retrofit measure each house needs over the next 30 years to reach zero carbon by 2050, so that each completed stage can be ticked off along the way.

The stock data that landlords hold is not always reliable, and rarely breaks down properties into types which are useful for costing retrofits. For example, two houses classified in the traditional way as solid brick-built three-bed semis can range from 70 square metres to 110 square metres of wall area and have completely different detailing requirements.

Quick scan devices can already help us catalogue archetypes but the development of this technology is in its early days. Energiesprong UK is planning to develop and test archetyping methods to make it easier for landlords to properly understand their stock before they start developing retrofit projects.

What has Destination Zero taught us? Understanding archetypes is useful and can get you ‘halfway there’ really efficiently. But don’t forget that the other ‘half’ will need doing – the property-specific details that need to be included in the final job.

Create a strong project team. Define clear roles and responsibilities to prevent duplication and make responsibility for each risk clear. This will also build buy-in with the wider team, from finance and legal to procurement.

For Destination Zero, Nottingham City Homes intended to be main contractor. Then, as people moved roles or left, and it became very clear how important it is to have the right people in the right places.

While NCH perseveres with the main contractor role for the moment, this has not been straightforward. Because both the organisation and the stock it manages are owned by Nottingham City Council, even the smallest job – from lintel replacement to pointing – has to be procured under public sector requirements. When grant funding is at stake, any delay is a big challenge. It may be that contracting out to a private sector company makes some of these issues easier and faster to deliver.

This isn’t to say it’s not possible for local authority, arms-length or other social housing landlords to take on the role of main contractor. In many ways, it makes sense, but where this approach is taken, planning and logistics management needs to be ramped up to ensure every piece of work is fully understood, the right providers are procured, and the right people allocated to the right roles.

What has Destination Zero taught us? Regardless of whether delivery is ‘in house’ or ‘contracted out’, it is critical to make sure that the right resources are in place with the roles and responsibilities clear.