A lender looking at an inefficient home faces a simple fork: lend against the building as it stands, or lend against the building it could become. A new cross-industry white paper, The Trillion-Dollar Housing Transition, published by the Sustainable Real Estate Forum (SREF) in October 2026, argues the second option is where the market now has to learn to work — and that the shortage holding it back is not money. It is the ability to originate, underwrite and execute credible transition pathways at scale.

The paper was written with contributions from GlobalABC, RICS, the European Mortgage Federation (EMF-ECBC), PATRIZIA, Optiml, pbb Deutsche Pfandbriefbank and INREV, and SREF will distribute it in the Blue Zone at COP31 in Antalya, Türkiye. Its lending chapter, from pbb, reduces the lender’s job to a three-part test: finance the cure, price the residual risk, and withdraw only when neither is credible.

What is SREF actually claiming?

The claim is that affordable housing and climate action have to be delivered together, and that capital is not the binding constraint on doing it. “A home that is cheap to build but costly to cool, unsafe in floods or heatwaves, or dependent on high-carbon materials is not affordable over its lifetime,” the paper states. The bottleneck, in SREF’s account, sits one step earlier than the money: in whether the market can produce enough well-evidenced, underwritable retrofit and building pathways for the capital to attach to.

The scale behind that claim is large by any measure. UN-Habitat estimates that by 2030 three billion people will need access to adequate housing — around 96,000 new affordable and accessible homes every day. Buildings’ operational emissions reached 9.9 GtCO₂ in 2024 and, according to UNEP, would need to fall by 56% by 2030 to align with a net-zero pathway. Roughly 80% of growth in building floor area through 2030 is expected in emerging and developing economies, where underwriting capacity is thinnest.

Where does the “trillion-dollar” figure come from?

“Trillion-dollar” is the paper’s framing of the overall scale, not a single line item. SREF’s founder and CEO, Peter Panayi, puts it this way: “The housing transition is a trillion-dollar challenge, but it is also a trillion-dollar opportunity.” The hardest number underneath the framing comes from UNEP: cumulative investment in building energy efficiency needs to reach around USD 5.9 trillion by 2030, compared with roughly USD 2.3 trillion invested between 2015 and 2024.

The investor side of the ledger supports the “capital is available” half of the argument. €117 billion was raised for non-listed real estate in 2025, and 87% of surveyed managers expect the amount raised to increase over the next two years. INREV estimates Europe needs more than two million new homes a year — around 650,000 more than it builds today — requiring about €153 billion of additional investment each year. The question the paper presses is not whether that money exists. It is whether lenders can tell, home by home, which transition plans deserve it.

What does “finance the cure” mean in practice?

It means the lender’s first question about a poor-performing home changes. Instead of asking whether the asset is financeable today, the lender asks whether it can become financeable through a pathway that is credible, funded and capable of being monitored. As Lara Knapwost, Head of ESG at pbb Deutsche Pfandbriefbank, writes in the paper: “Real estate transition is not primarily about buildings that are already efficient and financeable today. The task for lenders is to identify the assets that can become financeable through a credible, funded and monitorable pathway, and to actively support them.”

Each of those three adjectives does work. Credible means the retrofit or improvement plan is technically real for that building, not a generic pledge. Funded means the money for the works is actually assembled, including any subsidy or affordability support the household needs. Monitorable means the lender can check, over the life of the loan, whether the pathway is being delivered. A plan that fails one of the three is not a cure — it is a hope, and the test says not to price it as one.

This is where the desk work already familiar to BC ESG readers connects. Deciding which measures come first in an existing building is the problem the Retrofit Priority Stack for Existing Buildings works through; the SREF test adds the lender’s side of the same table — which of those stacked measures, properly sequenced and funded, turns an unfinanceable asset into a lendable one.

How should lenders price the residual risk that remains?

Even a well-funded cure leaves risk behind: the works may underperform, energy prices and policy may move, and some homes will still sit below standard at the end of their pathway. The paper’s second instruction is to price that residue openly rather than pretend the cure erased it — or use it as a reason to refuse the loan outright.

The valuation profession is where this pricing is supposed to become visible. RICS and EMF-ECBC argue that transition risk should become a material input to property valuation where it is supported by evidence. “Where transition risk is material and evidenced, valuers should be supported to reflect it,” says Sander Scheurwater, Head of Benelux at RICS. “The market’s ability to price both action and inaction will be central to the housing transition.” His colleague Gina Ding, RICS Head of Public Affairs Europe, describes the machinery: “Standards create the common language, data creates the evidence, and skilled valuers turn that evidence into professional judgement. When valuation is transparent, capital can tell apart the homes that need investment from those where investment protects value.”

Pricing inaction matters as much as pricing action. A lender who prices only the risk of a retrofit pathway, and never the risk of holding a book of homes with no pathway at all, will systematically make the wrong call — the stranded-asset end of transition risk arrives through the loans that were never restructured, not just the ones that were. Jennifer Johnson, Deputy Secretary General of EMF-ECBC, ties the threads together: sustainability, valuation and mortgage finance have to align, with a robust understanding of how energy performance relates to property value and financial risk.

Why can a credible plan still fail to deliver?

Because a spreadsheet is not a building site. PATRIZIA and Optiml show that a portfolio can have a technically credible decarbonisation plan and still fail to deliver it — because contractors are unavailable, permits take too long, grid capacity is constrained, or households cannot absorb the cost. Nico Dehnert, co-founder of Optiml, is blunt about the substitutes: portfolios “will not be delivered through ESG reports, generic benchmarks or static plans,” but through “credible, investable pathways that connect building reality, financial goals, affordability and execution constraints.”

So underwriting a pathway means underwriting its delivery chain, not just its engineering. Shreya Sheth of PATRIZIA calls the standard “decision readiness”: multiple investable pathways compared through a common financial and transition logic, so when one route blocks — a permit stalls, a contractor shortage bites — the financing can move to another route instead of dying.

What do lenders need before they can do this at scale?

The paper’s closing chapter, from INREV, answers with an Institutional Housing Compact: institutional capital can scale where three conditions hold. Policy must be stable, so a pathway underwritten today is not stranded by a rule change tomorrow. Affordability obligations must be explicitly funded, rather than silently loaded onto borrowers or lenders. And evidence must be common from asset to fund, so risks, returns and outcomes stay comparable as a home’s data travels up into a portfolio. “Capital follows the compact,” writes Jeff Rupp, INREV’s Director of Public Affairs: “stable rules, funded affordability and evidence that survives from asset to fund.”

That evidence condition is the one lenders control most directly. The discipline of assembling climate and continuity evidence a lender can actually rely on is covered in BC ESG’s Lender and Investor Evidence Pack, and the wider lending and disclosure context sits in ESG in Banking and Investment: Risk, Lending, and Disclosure. GlobalABC’s opening chapter makes the matching point at country level: global commitments only convert into housing when they become country-owned delivery systems.

And withdrawal? The test’s third clause is deliberately narrow: a lender withdraws only when neither side works — no credible cure can be financed and the residual risk cannot be honestly priced. It is the last resort of the test, not its default.

Frequently asked questions

What is The Trillion-Dollar Housing Transition?
It is a white paper published by the Sustainable Real Estate Forum (SREF) in October 2026, with contributions from GlobalABC, RICS, EMF-ECBC, PATRIZIA, Optiml, pbb Deutsche Pfandbriefbank and INREV. It argues that affordable housing and climate action must be delivered together, and it will be distributed in the Blue Zone at COP31 in Antalya, Türkiye.

Why does the paper say capital is not the constraint?
Because the investment need — UNEP estimates cumulative building energy-efficiency investment of around USD 5.9 trillion is needed by 2030 — sits alongside demonstrated investor appetite, including €117 billion raised for non-listed real estate in 2025. The paper argues the binding limit is the market’s ability to originate, underwrite and execute credible transition pathways at the scale the capital requires.

What is the lender’s three-part test in the paper?
From pbb Deutsche Pfandbriefbank’s chapter: finance the cure, price the residual risk, and withdraw only when neither is credible. In practice: first ask whether a home can become financeable through a credible, funded and monitorable improvement pathway; then price whatever transition risk remains, transparently, through valuation; and treat withdrawal as a last resort.

What does “residual risk” mean for a home that has a retrofit plan?
It is the transition risk left over after the planned works: underperformance of the measures, energy-price and policy movement, and any gap between the home’s end state and the standard the market will expect. RICS argues valuers should reflect that risk in valuations where it is material and evidenced — alongside the risk of inaction, which often goes unpriced.

Does this change anything for an individual borrower today?
Not directly — nothing in the paper is a lending decision about any individual home. It signals direction: lenders are being urged by their own industry bodies to build underwriting that rewards credible improvement pathways and to put transition risk into valuations. Whether and when any specific lender adopts that is that lender’s decision.

Sources

• SREF / PR Newswire launch release for The Trillion-Dollar Housing Transition (28 October 2026), including quotes from Peter Panayi (SREF), Lara Knapwost (pbb Deutsche Pfandbriefbank), Sander Scheurwater and Gina Ding (RICS), Jennifer Johnson (EMF-ECBC), Shreya Sheth (PATRIZIA), Nico Dehnert (Optiml) and Jeff Rupp (INREV), and figures attributed there to UN-Habitat, UNEP and INREV.

This article is general information about a published industry paper. It is not investment, lending or financial advice, and it is not a recommendation for or against any product, property or course of action.