David Partridge played a key role in the King’s Cross regeneration. What’s next on his agenda?

He is now focusing on two roles: chairing the governance board for a UK net zero carbon building standard, which he has done since 2022, and a new job chairing Senze, a retrofit data business. But why enter the retrofit market now – and why is he specifically targeting social landlords?

“I’ve always had a real interest in designing buildings appropriately,” says Mr Partridge as we meet in a cafe in Coal Drops Yard. He points out that King’s Cross runs on a giant district heat network that powers all seven million square feet of offices, homes, shops and restaurants. Currently the energy centre uses gas-fired boilers, but Related Argent has committed to decarbonising these.

Mr Partridge is also three years into his own personal retrofit project upgrading his second home, a converted barn in Norfolk, with solar panels, battery storage, mechanical ventilation and a ground source heat pump (his main residence is in the King’s Cross regeneration area). “I’ve completely de-fossil-fuelled,” he says. “Previously, I was literally bringing £7,000 worth of oil a year there and pumping it into a tank, hoping someone wouldn’t steal it before I actually used it.” Now, he sends data into the government every quarter and gets a cheque back for using low-carbon heating under the Renewable Heat Incentive scheme (this coalition-era scheme closed to new entrants in 2022).

The project is not yet finished, so he is unable to conclude whether his upgrades will save him money on his energy bills. “This is why deep retrofit is a problem,” he says. A lighter touch may be just as effective at preventing heat loss. In his new job working with social landlords, he says, “we’ve literally saved the housing association tens of thousands of pounds” because they changed plans after “we said you’re going to end up with exactly the same heat loss as before and you’re going to spend £50,000 on it”.

Senze, Mr Partridge’s data tool, aims to measure the actual performance of buildings, starting initially with social housing. Why this sector? “There’s a societal desire to do good, which is something that’s driven me all my life,” he says. Plus, “you’re already tapping into funds”. Social landlords in England must upgrade all their homes to an Energy Performance Certificate (EPC) Band C rating by 2030; a social housing retrofit supply chain is forming to achieve this. The government is scaling up its Warm Homes grant funding programme, while banks such as Lloyds and Barclays have partnered with the National Wealth Fund to offer low-interest loans for retrofit projects.

Lenders increasingly appreciate the social impact that can be created by retrofitting social housing. Private landlords see that their tenants are willing to pay higher rent for lower bills, while social landlords can lift their residents out of fuel poverty, with the bonus of lower rent arrears. By contrast, the return on investment of retrofitting a home as an owner-occupier is less obvious at present, barring a personal desire to save the planet and increase comfort.

“The difficulty [with private sector retrofit], from a start-up point of view, is it’s much easier to get to 1,000 homes all owned by one person than it is to get to 1,000 mortgage owners,” says Mr Partridge. “To scale, [we’re] going after the bigger landlords… Then we can prove what technology really works.”

Senze uses EPC data and postcodes to analyse a landlord’s portfolio and work out which homes are most at risk of fuel poverty or in need of intervention. The company then goes into said homes and measures them using light detection and ranging (LiDAR) technology, creating a 3D digital model of each room. It also installs temperature and humidity sensors in each room to measure heat loss. From there, it can estimate the carbon savings and return on investment of various improvements – for example, double-glazing – over five or 10 years.

“People who are coming in on this are not necessarily just the housing associations but large banks looking to lend to this sector, not based on government,” Mr Partridge says. “People like Lloyds and Barclays, they need data in order to drive their lending and then underwrite their revenue decisions afterwards and prove that what they’ve lent money on is actually resulting in upticks in performance.”

Live heat loss data is all well and good, but isn’t there a big EPC-shaped elephant in the room? Ultimately social landlords will be measured on this certificate, which is currently based on fixed assumptions about temperatures and fuel prices. But the government is changing EPCs to allow real-time data as part of the assessment process from 2026. “The whole industry is telling [government] you’ve got to go for real data,” says Mr Partridge. “We’re anticipating that shift.”

Speaking of the development industry, I ask Mr Partridge to explain his other role developing the UK Net Zero Carbon Buildings Standard. This is about the sector coming together to agree on a single definition of what a net zero carbon building is, he says. The team includes the Royal Institute of British Architects, the Royal Institution of Chartered Surveyors, the UK Green Building Council and the Building Research Establishment.

It is a voluntary standard designed to be more exacting than government regulations, including the upcoming Future Homes Standard; it covers new build and retrofit buildings of all types, not just homes. A pilot standard was launched in September 2024 and at the end of this year, the board will publish the final definition, “which we hope will get adopted by the industry as their gold standard”. (Various large developers and construction companies have already sponsored the creation of the standard including British Land, Mace, The Crown Estate and BAM Construction.)

The standard is less about looking at whole-life carbon and the construction supply chain and more about setting upfront limits for energy use. “One of the things that we’re really, really focused on in the standard is reporting actual performance, not theoretical performance, which is the problem with EPCs and it’s also slightly the problem with whole-life carbon, because you have to extrapolate for the next 50-60 years,” he says. “You will only get a definition of net zero carbon for your building if you prove up front how much has gone into it… and how you’re actually using it.”

At the standard’s core is the Climate Change Committee’s calculation of how much carbon the UK’s property sector should be allowed to emit to stand a reasonable chance of mitigating global warming to 1.5°C. As counterintuitive as it sounds, the more developers that adopt the standard, the less strict it must be, “because everybody’s carrying the burden, rather than 20% having to build to a much stricter limit”, Mr Partridge says. “We’ve had to put some fairly heroic assumptions in about how many people within each of those sectors would actually adopt it.”

Having dissected his current jobs in sustainability, I ask Mr Partridge about King’s Cross and what he has learned about steering successful regeneration projects. “Every place will have a completely different mix of social demographics and transport, health-related issues and local economics,” he says. “But what you can do is apply some of the basic lessons… making sure that you put all the infrastructure in first, making sure you have the right combination of landowner, developer, local authority and transport provider and aligned incentives, so if one does well, everybody else does well.”

What really made King’s Cross work, he says, even during the “really tough” early years between 2008 and 2011, was that “everybody was incentivised to do something”. “Because the landowners were in partnership, they weren’t sitting around waiting for values to go up. They were in it, and so they were like, ‘For my land to be worth anything we need to do something.’

“What that involved was setting up a few blocks and using all the money that came in from those blocks to build streets and squares and district heating networks and underground infrastructure. So that when we could begin to start building speculatively, most of the infrastructure was actually there.”

He calls it creating a feeling that “everything you do will make my front door better”.

“It’s about getting the virtuous circle going… which does involve trusting each other, and sometimes you have to give a little bit away to get some more back later.” 

Collaboration and trust: crucial for regeneration, but crucial, too, for social landlords if they have any hope of meeting their retrofit goals.