A North Yield case study · Tees Valley
The state of Tees Valley's homes
We mapped the latest Energy Performance Certificate for all 238,159 homes across the Tees Valley's five councils. Half fall below EPC C — the efficiency standard national policy is built around — yet most are only a step away from it. This is the full picture: where the region stands, why, and what it would take to fix.
The picture in brief
If you read nothing else:
- 01 Half the region sits below C. 51.9% of homes fall below EPC C — but the biggest single group is D, only just short of the line, not F or G.
- 02 Almost all of it is fixable. If every home took the improvements its assessor recommends, 95% would reach C or better — up from 48.1% today.
- 03 The challenge is concentrated. Older stock — Victorian and Edwardian terraces — and the private rented sector lag furthest behind.
- 04 Social housing proves it's doable. Social landlords have already pulled their stock well above the regional average.
- 05 2030 makes it urgent. Every rented home must reach EPC C by 2030 — turning a slow drift into a hard deadline.
Why EPC C is the line
Those findings all turn on a single line — EPC C — so before the detail, the basics. Every home that's sold or rented needs an Energy Performance Certificate (EPC): a rating from A (most efficient and cheapest to run) down to G (least efficient). We took the latest one for all 238,159 homes across the Tees Valley's five councils.
The line that matters is EPC C. It's the standard government policy is built around: homes at C or above are relatively warm and cheap to run. Homes below C (rated D to G) cost more to heat, produce more carbon, and — if they're rented — fall short of the minimum efficiency standard ministers are expected to require in the coming years.
On this page, greener areas have more homes at C or above; redder areas have more homes below C — where the biggest efficiency gains are waiting.
How the region's homes are rated
So where do the region's homes actually fall against that line? Here's the whole stock, A to G — and EPC C cuts straight through the middle of it.
Here's the surprise hiding in the numbers: most below-C homes are barely below it. D alone is 38.8% of every home in the region — the single largest band, and roughly three in four of all below-C homes. These aren't cold, failing houses; they're ordinary homes sitting a step or two short of C. The genuinely poor stock — F and G — is barely 2% combined.
Why it matters: a region whose shortfall is mostly D is a very different — and far cheaper — problem to fix than one full of F's and G's. It's the difference between topping up insulation and starting over.
Explore the map
That single bar is the region in aggregate — but the challenge isn't spread evenly. Here it is on the ground: every postcode district shaded by your chosen metric. Switch the view, then click a district (or pick one) to read its full breakdown beside the map, and find your own patch.
31 of 31 districts have data.
Meet the typical Tees Valley home
Districts and distributions are one way to see it. But behind the averages is a real, recognisable home — and across the region one profile dominates the ones that fall short.
It's not a wreck — it's a solid, ordinary family home a few points short of C. Homes like it get the same shortlist from their assessor: loft and wall insulation, better heating controls, and low-energy lighting. None are exotic; most sit at the cheaper end of retrofit. Multiply this one home by the 123,543 below-C homes across the region and you have both the scale of the task and the size of the prize.
How the five councils compare
Homes like that turn up right across the map — so start with the broadest cut, the five councils. Every one has a majority of homes below C: this is a regional challenge, not one stuck in a single corner.
The striking thing is how little separates the councils — just 6.8 points between the best, Stockton-on-Tees (49.1%), and the highest-need, Redcar & Cleveland (55.9%). This isn't a problem stuck in one corner of the region: every council has a majority of homes below C. Darlington and Redcar & Cleveland edge ahead on need, reflecting their older terraced and rural housing.
Bear in mind: a single council's average hides a lot. Within any of them, neighbourhoods range from mostly-C to mostly-D — as the map above makes clear — and councils with more new-build estates (and more recent sales) will look a little better here.
The prize: what Tees Valley could be
Social housing proves what a funded programme can do. So how far could the rest of the stock go? Every certificate also models a home's potential — its rating if the recommended measures were fitted. Line today up against that potential and the headroom is startling.
The below-C share would collapse from 51.9% to just 4.9%. Bands A and B — nearly empty today — would become the norm. This is the modelled ceiling, not a forecast: it assumes every recommended measure gets fitted, which costs money and rarely all happens. But it shows the headroom is vast — and, as the next section shows, much of it is cheap.
Read it as: the gap between the two bars is the retrofit opportunity, in one picture.
The upgrade opportunity
That full potential is the long game. But a large share of it is within reach right now — homes a single step from C, and real headroom on the average home.
homes are rated below C but their assessor says they could reach C or better — that's 47% of all stock.
quick wins — D-rated homes within 5 points of a C, where a modest upgrade tips the rating.
average point uplift available per home (66.9 → 81.7 on the EPC scale).
This is the optimistic heart of the data: most below-C homes aren't stuck there. 111,881 of them — 47% of every home assessed — could reach a C, and the average home has room for a 15-point jump. For the region that's a vast, addressable retrofit opportunity; for owners and landlords, it's value waiting to be unlocked.
The catch: "potential" is the assessor's modelled best case — it assumes every recommended measure gets fitted, from loft insulation to a new heating system. That costs money and rarely all happens, so read "could reach C" as the ceiling, not a forecast. The quick wins are genuinely cheap; the deeper fabric work — solid-wall insulation especially — is where cost and disruption climb.
The rental challenge
So who is furthest from taking that opportunity? Split the stock by who owns it. Social housing has surged ahead; the private rented sector lags well behind — and with a 2030 deadline now set for rented homes, that's the gap that matters most.
The gap between social and private renting is the real headline. Social landlords have systematically upgraded their stock — only 33.6% sits below C — while privately rented homes (61.8%) look much like owner-occupied ones. With the minimum standard for rented homes expected to rise to EPC C, it's the private rented sector — tens of thousands of homes — that faces the steepest climb.
Worth noting: owner-occupied homes are actually the most likely to be below C (66%) — they're just not covered by rental rules, so improving them depends on owners choosing to act. A sizeable "unknown" group can't be classified, and the EPC-C standard for rented homes is now set for a 1 October 2030 deadline (more on what that means below), with the finer detail still being finalised.
A decade of change
With that deadline coming, is the stock improving by itself? On the face of it, yes: the share of certificates rated below C has fallen sharply — from a peak of 70.2% in 2014 to 39.2% in 2025. A decade of steady improvement. It's a real signal — but one worth reading carefully.
What it's telling us
Homes being certified today really are more efficient than those certified a decade ago. Building regulations for new homes have tightened repeatedly, and grant-funded insulation, better boilers and solar have all left a mark. The upward pull is genuine.
…and why to read it carefully
- • This isn't the whole housing stock. A home only gets an EPC when it's sold, re-let or newly built — so each year's figures reflect whatever changed hands, not every home in the Tees Valley.
- • An EPC lasts 10 years. A home assessed once may not reappear for a decade, so the line isn't the same homes getting greener — it's a rolling snapshot of whatever was assessed each year.
- • The mid-2010s peak is partly an artefact. 2014 was the busiest year for assessments (36,747 certificates) — likely driven in part by the assessment schemes of that era, which brought many older, less-efficient homes into the figures and pushed the below-C share up.
- • The ruler has changed. The way EPC scores are calculated (and the energy prices they assume) has been revised over the years, so an early-2010s rating and a 2020s rating aren't a perfect like-for-like.
Bottom line: new and recently-sold homes are clearly improving — but this chart shouldn't be read as proof that the region's existing homes have all got greener.
The same homes, revisited
Here's the catch in that trend: it counts fresh certificates, not the same homes over time. So follow the homes themselves. 82,881 have been assessed more than once — a genuine before-and-after — and comparing each one's first certificate with its latest tells us whether the stock is really improving.
average EPC-score gain between a home's first and most recent certificate — though the median is just +2.
of reassessed homes improved their score, and 6% came back exactly the same.
actually scored worse the second time — a reminder that EPC scores aren't a one-way ratchet.
Record-breakers
- Most improved home
- A bungalow in TS8 leapt 73 points — from an F (score 22) in 2019 to an A (95) by 2023. One TS21 home jumped even further on paper (a G scoring 1, up to an A at 96), but a starting score that low usually means a derelict shell being rebuilt from scratch.
- Most certificates
- One Darlington (DL1) home carries 16 certificates (2010–2022) — and after all that reassessing, it's still a D.
- Most improved district
- Central Middlesbrough (TS1) leads: reassessed homes there gained +7.8 points on average across ~3,900 properties, with Darlington's DL3 close behind at +6.5.
- Bungalows punch above their weight
- Bungalows dominate the biggest improvers — single-storey, with a lot of roof and floor to lose heat, so insulation delivers outsized gains.
The real headline isn't the +4.4 average — it's that more than a third of homes scored lower the second time round. A different assessor, a slightly changed method, or a feature no longer counted can all nudge a score down without anything physical changing.
Bear in mind: this only covers homes assessed more than once, which isn't a random sample — reassessments are usually triggered by a sale or a retrofit. So read this as the story of homes that changed hands or had work done, not of the stock as a whole.
What holds Tees Valley back
Whether a home improves or stalls, its starting point is set by what it's made of. Two things hold the region back above all else: how old a home is, and what type it is.
By property type
By construction age
Bands follow the official EPC construction-age categories, which track changes to Building Regulations rather than neat 10-year blocks — so their widths vary.
Age is the strongest predictor of efficiency. Homes built before 1900 average around 55 on the EPC scale — deep in band E — while those built most recently average close to 82, comfortably a C. The Tees Valley's Victorian and Edwardian terraces and its interwar estates are the hard core of the challenge. By type, bungalows fare worst — single-storey, with a lot of roof and floor to lose heat through — while flats do best, sheltered by the homes around them.
Bear in mind: these averages don't doom every old home — a well-insulated Victorian terrace can absolutely reach C; it just takes more work. Age, type, tenure and location all overlap, so these aren't fully independent effects, and construction age is sometimes estimated rather than known.
District league table
Age, type and tenure all pile up in the same places. Put them together and the region ranks cleanly, district by district — the ones with the most homes below EPC C, and so the most upgrade headroom, first.
| District | Homes | Avg score | Below C | |
|---|---|---|---|---|
| TS11 | 3,186 | 64 | 67.3% | |
| TS9 | 27 | 55 | 66.7% | |
| DL3 | 15,033 | 63 | 65.5% | |
| TS13 | 2,881 | 63 | 62.9% | |
| TS5 | 11,930 | 64 | 62.6% | |
| TS12 | 7,756 | 64 | 60.9% | |
| TS1 | 8,218 | 64 | 58.5% | |
| TS20 | 7,301 | 66 | 57.7% | |
| TS7 | 6,827 | 67 | 56.3% | |
| TS14 | 5,891 | 66 | 55.7% | |
| TS25 | 13,601 | 67 | 55.3% | |
| TS10 | 13,063 | 66 | 54.4% | |
| TS26 | 9,360 | 66 | 54.4% | |
| TS23 | 9,127 | 66 | 54% | |
| TS19 | 12,418 | 67 | 52.9% | |
| DL1 | 17,312 | 66 | 52.2% | |
| DL5 | 659 | 66 | 52% | |
| TS16 | 3,493 | 69 | 51.1% | |
| TS3 | 11,550 | 67 | 49.1% | |
| TS18 | 10,210 | 67 | 48.1% | |
| TS27 | 1,623 | 69 | 48.1% | |
| TS6 | 10,556 | 68 | 48% | |
| TS21 | 1,657 | 68 | 46.7% | |
| TS24 | 9,659 | 68 | 45.7% | |
| TS17 | 15,267 | 69 | 44% | |
| TS4 | 7,262 | 69 | 41.2% | |
| TS15 | 4,205 | 71 | 40% | |
| TS22 | 3,703 | 74 | 34.5% | |
| DL2 | 5,450 | 72 | 34% | |
| TS8 | 8,329 | 72 | 32.4% | |
| TS2 | 602 | 72 | 26.6% | |
Read top-down, this is a targeting list. The districts with the most homes below C are typically the older, town-centre and former-industrial areas; the greener foot of the table is newer, suburban and edge-of-town housing. For anyone planning retrofit — or hunting value-add property — the top of the table is where the need, and the opportunity, is concentrated.
Read it in the round: a small district with a high below-C share affects fewer homes than a big district with a moderate one, so weigh the "homes" column against the percentage. And as everywhere here, figures cover only each district's Tees Valley portion.
The most-recommended upgrades
So from where the work is needed to what the work actually is. Across all 238,159 homes, these are the improvements assessors recommend most often — the practical to-do list behind the whole story.
Together these sketch a clear retrofit roadmap. The cheapest wins — low-energy lighting and better heating controls — cost little and appear on huge numbers of homes. The bigger prizes are fabric measures: loft, floor and especially wall insulation, where the older stock loses most of its heat. And solar — panels and hot water — tops the list, a reminder of how many roofs across the region still have none.
The catch: these are the standard suggestions generated by the EPC model, not a costed, surveyed plan for any individual home. "Recommended" doesn't always mean "worth it", and solar appears almost everywhere simply because the model proposes it wherever there's roof space — a real upgrade plan needs a proper assessment of the property.
It's not just bills — it's carbon
Every one of those upgrades does double duty. A home's rating tracks its emissions as well as its bills, and the gap between a below-C home and a C-rated one is wide.
average CO₂ a year from a below-C home
average CO₂ from a home at C or above
as much carbon from the average below-C home
A typical below-C home emits around 5 tonnes of CO₂ a year — more than double the 2.4 tonnes of a C-rated one. Across the 123,543 homes below C, that's a large, addressable slice of the region's domestic emissions. Every upgrade that lifts a home toward C cuts its carbon as well as its bills — which is why councils chasing net zero and households chasing lower bills are, for once, pulling in the same direction.
What this means for Tees Valley
Add it all together and the picture is remarkably consistent: most homes sit below EPC C today, but the large majority could reach it — and much of that is cheap, near-term work. That's the challenge and the opportunity in a single line, and it lands differently depending on who you are.
For residents
123,543 homes rated below C means higher energy bills and colder winters. Upgrading toward a C typically cuts running costs and carbon — and 111,881 of them already have the potential to get there.
For the region
Bringing every below-C home up to standard is a region-wide retrofit programme — insulation, modern heating and solar at scale — and with it, local jobs, investment and real progress toward net zero.
For landlords & investors
With rented homes required to reach EPC C by 2030 — backed by a £10,000 spending cap — the 45,016 homes within touching distance of a C are the cheapest early wins, protecting rental income and adding value.
This data is how we source deals
North Yield uses this dataset every day to find below-C homes with genuine value-add headroom for investors — the quick wins before the 2030 deadline makes them expensive. If you're building a portfolio in the Tees Valley, book a free consultation and we'll show you where the opportunity sits.
Own or let a home in the Tees Valley?
Our in-house assessor can tell you exactly where your property stands — EPCs from £65, certificate within 24 hours of the visit.
Further reading
The 2030 EPC deadline: what it means for your home →
A legal deadline, a £10,000 spending cap and a new scoring system are on the way. What's changing for Tees Valley homeowners and landlords — and where to start.
GuideA deep dive into Teesside property investment →
The economic drivers, regeneration projects and data behind the region's investment case.
About this data
Source: the official Energy Performance of Buildings Register for England and Wales (Ministry of Housing, Communities and Local Government), used under its published conditions for data analysis. All analysis, aggregation and any errors are North Yield's own. We publish area-level statistics only — never individual addresses.
What de-duplication saves us from
The busiest address in the whole dataset has racked up 16 EPC certificates — including 14 lodged on the very same day in 2010 — with its rating wandering from an E, down to an F, and eventually back up to a D. Count every certificate and that one home shows up sixteen times; count homes, and it's a single (rather weary) D. There are 82,881 Tees Valley homes with more than one certificate on file — which is exactly why we keep only the most recent.
Based on domestic Energy Performance Certificates for the five councils of the Tees Valley Combined Authority — Darlington, Hartlepool, Middlesbrough, Redcar & Cleveland and Stockton-on-Tees — from the UK Government's open EPC register.
The register logs every certificate ever lodged, so a home that's been reassessed over the years appears more than once. To count homes rather than certificates, we de-duplicate by property, keeping only each home's most recent certificate — so the 238,159 figure, and every rating breakdown, reflects homes as they stand today (the roughly 1% of certificates with no property identifier are kept as-is). Postcode districts are clipped to the combined authority boundary, so only the Tees Valley portion of each is shown, and figures are aggregated to district level — no individual property or address is identified.
The one exception is the “decade of change” chart: it counts all certificates lodged each year, since it's a record of assessment activity over time, not a snapshot of the stock.
Social housing: the success story
But one part of the stock bucks the pattern in every council — and it's the clue to everything that follows. Social-rented homes are the region's most efficient tenure: just 33.6% sit below EPC C, against 51.9% of homes overall. Years of funded, systematic upgrades have pulled them well ahead. Here's how each council area's social stock compares.
The contrast is stark: Darlington's social homes are just 26.1% below C, against 51.9% across all homes in the region. Social landlords have upgraded their stock at scale — insulation, modern heating and better controls — and it shows in every council area. It's a working blueprint for the rest.
Bear in mind: this is the EPC tenure field — it flags a home as socially rented, not who owns it. Most of the region's social stock was transferred from councils to housing associations years ago, so it's largely not council-owned. And the EPC C-by-2030 minimum is a private-rental rule; social housing is driven separately by the Decent Homes Standard and government retrofit funding, with a parallel 2030 ambition still being finalised.