To fix the climate, retrofit your home

New zero-carbon homes are nice. Old homes are the solution.

Simple climate action   //   I S S U E   3 3    //   H E A T I N G

Renting a home is an energy suck...

By Jemima Kiss

I’ve never had the luxury of owning my own home, but the rental place where I live is a good example of why most 20th-century homebuilding isn’t fit to achieve net-zero emissions in the 21st century. As is common in California, our house is wood-framed and has a flat, wood-and-tar roof. There’s no insulation in the walls or the roof (there is no attic space), and the long front of the house is floor-to-ceiling glass. Which sounds nice, but it sucks heat out of the house in winter and traps heat in the summer. In short, it couldn’t be less energy efficient.

We pay extra for solar power, but what this house really needs is a complete renovation: double glazing, a new insulated roof, insulation in the walls and floor. All of this would cost a significant percentage of what the house is worth. There’s no incentive for our landlord to do that.

Many tenants are in the same position. But in Europe, where a high percentage of citizens rent rather than own, there’s far more incentive for the private and public sector to create zero-carbon housing stock. 

This week, our writer Willem Marx shows how the Dutch started a zero-carbon revolution for publicly-owned housing spreading throughout Europe.

Energiesprong wants every home to be net-zero

An European initiative building an industry from scratch

By Willem Marx

The homes were terraced, pale-brown brick, and woefully energy inefficient. The two-story townhouses in Hem, a small town in the northeast of France, kept residents sweltering in the summer and shivering in the winter. Utility bills were crushing. 

But ten of the townhouses were finally due for an upgrade in 2018. The private company Vilogia owned them as part of its contract with the French government to provide affordable housing, known as social housing in Europe. Vilogia owns thousands of other properties just like them across the whole of France, where lower-income tenants rent properties at below-market rates. 

Even developers of new buildings have found it “impossible” to reach net-zero in France, recalls Fabien Lasserre, the company’s head of technical innovation. But he and his colleagues were preparing upgrades for the old homes in Hem that had to last decades. That presented an added risk: any improvements could become obsolete in a few years if French regulators imposed stricter residential emission standards. 

Lasserre decided to try an experiment that had never been done at scale in France: a zero-carbon retrofit for old homes. 

After winning approval from his CEO, Lasserre got to work. Over the course of three months, his team installed new polyurethane facades to each of the terraced houses to avoid heat loss. Above the existing roofs, they built timber and steel structures filled with insulation panels. Solar panels were installed on all the roofs. Most of these components were manufactured or assembled in a nearby factory, rather than created onsite, to save money. Heat recovery ventilation systems extracted stale and moist air from each home, recovered the heat, and then used that heat to warm fresh filtered air.

The cost to upgrade each unit was around €120,000 ($145,000), slightly higher than a conventional retrofit. But energy use fell by 75%, enabling the solar panels to handle the remainder. Just as important, annual energy bills fell by half to just €900 ($1085) (most of which were outmoded energy taxes the French government is considering abolishing). 

“It was a kind of revolution,” Lasserre says of the project. The upgrades ensured expensive upgrades wouldn’t be needed in the future, and tenants could be more comfortable for decades to come without having to leave their homes during refurbishments.

Other large affordable housing owners in France soon took note. Three years later, Vilogia plans to deliver dozens of zero-carbon apartments and refurbish 160 single-family homes in the nearby community of Wattrelos, France. Another 800 homes are due for completion by 2025. The firm has partnered with its peers and the local government to expand this effort dramatically in the years ahead. 

Replicating zero-carbon homes anywhere

It can’t come soon enough: 17% of the world’s total greenhouse emissions come from housing. Most of those aren’t from new buildings, but from existing properties. The great challenge is how to retrofit millions of buildings to meet a net-zero standard.

The Dutch may have found a way. 

Lasserre’s inspiration came from a business concept he had learned about from European colleagues called Energiesprong, a Dutch word for “energy jump.” It began back in 2010 as a vague idea inside the Netherlands ministry for home affairs. An unspent portion of that year’s innovation budget, just under €50 million, needed to be allocated. It was decided the funds should be spent on reducing carbon emissions from the country’s housing sector. 

Private sector individuals with a range of backgrounds pulled together in a government-funded business incubator. They brought professional expertise from housing development, energy efficiency, and marketing, according to Silicon Valley veteran Ron van Erck, who joined the effort early on and now oversees international development at the not-for-profit Energiesprong Foundation. 

But it was an unconventional marriage that turned out to be exactly what the industry needed. “If we are not figuring out something that's more compelling for people to buy—that actually brings the building stock closer to where we need to go—this is going nowhere,” says van Erck, describing the Dutch government’s strategy. “This is not where we would like to end up.” 

A decade after its inception, the group is now thinking about retrofitting as far more than materials. They’ve created a commercial ecosystem in the Netherlands for businesses that are willing to rethink and then tackle the necessary housing transformation. They built a dedicated factory for insulation panels, so as to drive down on-site costs; convinced banks and local governments to offer attractive financing for homeowners; and consulted tenants on the buildings’ aesthetics. 

The soup-to-nuts approach means Energiesprong promoters - like local housing organizations - can refurbish homes that are visually desirable, with lower energy costs and carbon footprints. But Energiesprong is also a market development tool: a public-private model that can be replicated in developed nations seeking to reduce its carbon footprints. By building out a viable ecosystem of companies that work together to deliver zero-carbon retrofits, it scales up a service for millions of homes.

Government, meet the zero-carbon home industry

Almost 6,000 properties in the Netherlands have already undergone an energiesprong makeover. There are at least as many planned in France — including Vilogia’s efforts — plus hundreds more under construction in the UK, Germany and Italy, and even a few dozen planned for New York state through a $30 million program called RetrofitNY.

So far, the concept has only worked in a small number of locations, and only with significant financial and logistical backing from government. The task ahead, UK researchers say, means a radical change to the business models behind residential renovation, and a shift in how governments pay for it. Rather than simply paying for building upgrades, governments need to support the creation of a viable commercial industry aimed at eliminating emissions from buildings (similar to how NASA is nurturing a commercial space flight industry, rather than just building and buying rockets). Energiespong aims to do this by directing funds toward early adopters of effective technologies, sourcing financial support for them until they reach commercial viability.

With tens of millions of homes across North America and Europe needing to be upgraded in the coming decades, old techniques aren’t up to the challenge. There may never be enough workers to retrofit all the homes that require energy efficiency upgrades, house by house with individual surveys, argues Ian Hutchcroft, head of Energiesprong’s market expansion efforts in the UK. Instead, retrofit efforts must come to rely on the expanded use of digital tools, like portable 3-D laser scanners that can measure millions of data points on an individual property, then instruct an assembly line nearby to build bespoke insulation panels for each home. 

“We need a new industry that's capable of delivering at scale in a cost-effective way,” he says. “We're very much about industrializing the housing retrofit and new-build process as well.” He points to the automobile industry as a model: thousands of customized cars a day roll off assembly lines. 

Hutchcroft’s team now talks with the British government “every week” to expand the market beyond social housing groups and public sector landlords. He’s encouraged by their willingness to listen. Given the chance to present a few slides to British Prime Minister Boris Johnson, he thinks he could be persuasive: “I think we’ve got that compelling narrative, I think we have the pitch, and we can point to where it is working, and point to the companies that consider this to be the future.” 

The ultimate goal, says Hutchcroft, is raising awareness among homeowners who demand zero-carbon retrofits. Supply will follow. “Some carrots and sticks from government,” he explains, “will drive householders to put their hands up and say, ‘Yes, please do this to my house too.'” 

Hothouse is a weekly climate action newsletter written and edited by Jemima Kiss, Mike Coren and Jim Giles. We rely on readers to support us, and everything we publish is free to read.