If you’re weighing up insulation, a heat pump, solar panels or new glazing, there’s a good chance the sales pitch you’ve heard includes some version of “it’ll pay for itself when you sell.” It’s a reasonable question to ask, and it deserves a proper answer rather than a marketing one. So we’ve gone through the actual UK research - house price studies from Nationwide Building Society, Rightmove and Knight Frank, plus a landmark government-commissioned academic study - to see what the data really shows, not what installers would like it to show.
The short version: yes, there is a measurable, repeatable price effect from having a better EPC rating, and it’s bigger than most people assume for homes moving up from a poor rating. But it’s also smaller than the headlines sometimes suggest, it varies a lot depending on your starting point, and for most homeowners it shouldn’t be the main reason to retrofit. Read on for the actual numbers, where they come from, and the caveats that rarely make it into the sales brochure.
What Nationwide’s House Price Research Actually Found
The most rigorous, regularly-updated UK data on this comes from Nationwide Building Society, which analyses its own mortgage lending data to isolate the effect of EPC rating on sale price, controlling for other factors like location, size and property type. Nationwide has repeated this analysis several times since 2020, and while the exact numbers have moved around a little with each update, the pattern has stayed remarkably consistent.
Nationwide’s most recent update, published in June 2026, found that for owner-occupied homes:
- Properties rated A or B sold for a modest 1.6% premium compared with otherwise similar homes rated D - around £4,500 at average English house prices.
- Properties rated C or E showed little to no noticeable price difference compared with D-rated homes.
- Properties rated F or G sold for around 1.4% less than comparable D-rated homes - a discount of roughly £4,000.
Earlier versions of the same Nationwide analysis found broadly similar, if slightly larger, effects - premiums for A/B-rated homes have ranged from around 1.6% to 2.8% across different updates, with F/G-rated homes trading at a discount of somewhere between 1.4% and 4.2%. The precise figure shifts a little year to year as the housing market moves, but the direction and rough scale of the effect has been consistent for half a decade: a real but modest premium for the best-rated homes, and a real but modest discount for the worst-rated ones.
One detail worth flagging is what happens in the buy-to-let market, where the effect is much larger. Nationwide’s research found A or B-rated buy-to-let properties commanding a premium of around 12.2% over D-rated equivalents - more than seven times the effect seen among owner-occupiers. That’s almost certainly because landlords are pricing in future regulation risk (minimum EPC requirements for rented properties have been a live policy issue for several years) rather than pure resale appeal. It’s a useful reminder that “the market values EPC ratings” isn’t one single number - it depends heavily on who’s buying and why.
This isn’t a brand new finding dressed up as news, either. The link between energy efficiency and sale price has a longer academic track record than most retrofit marketing lets on. Back in June 2013, a government-commissioned study carried out by researchers at Cambridge University for the then Department of Energy and Climate Change looked at repeat-sales transactions covering almost 326,000 dwellings across England between 1995 and 2011 - at the time, described as the most comprehensive research of its kind. Its conclusion was that energy efficiency is “a key factor influencing the sale price of most residential dwellings in England.” The exact percentages from that study are more than a decade old now and shouldn’t be taken as current pricing, but it establishes something useful: this isn’t a fringe theory that’s popped up alongside recent net-zero policy pressure, it’s a relationship that’s been observed in large-scale UK transaction data for well over ten years.
The Bigger Jumps: What Happens When You Move Off a Poor Rating
The Nationwide figures compare bands against a D rating, which is roughly where the average English home currently sits. But a lot of retrofit decisions aren’t about moving from C to B - they’re about moving a genuinely poor-performing, older home from an E, F or G rating up to a C. Two separate pieces of research have looked specifically at this kind of larger jump, and both found a noticeably bigger effect than the Nationwide owner-occupier figures suggest.
Rightmove’s research, published in August 2023, analysed 300,000 properties that had sold twice within a 15-year period, each time with a valid EPC certificate in place, and measured the additional “green premium” on top of normal local house price growth. It found:
- A move from D to C was associated with a 3% premium, worth around £11,157 at the national average asking price at the time.
- A move from E to C was associated with a 7% premium, around £26,033.
- A move from F to C was associated with a 15% premium, around £55,786.
Knight Frank published separate research in October 2022, based on around 30,000 properties that had been retrofitted over a five-year window, comparing valuations before and after the works. Its figures were strikingly close to Rightmove’s for the smaller jump, and even larger for the bigger ones:
- D to C: roughly 3% uplift (around £9,003 in Knight Frank’s sample).
- E to C: roughly 8.8% uplift (around £29,289).
- F or G to C: roughly 19.6% uplift (around £64,444).
Two independent studies, using different methodologies and different samples, arriving at a similar D-to-C figure (around 3%) and both showing the uplift scaling up sharply the worse your starting rating is - that’s a reasonably solid pattern, not a one-off headline. It also lines up with basic economic logic: buyers (and their surveyors, and increasingly their mortgage lenders) are far more wary of a G-rated home with single glazing and no loft insulation than a C-rated one, so the discount priced in at the bottom end is larger, and closing that gap is worth more.
It’s worth being realistic about the cost side of this too. Knight Frank’s research put the average cost of retrofitting a D-rated home up to C at around £5,500, rising to £10,000-plus for homes starting at F or G. Whole-house retrofits that combine several measures - insulation, glazing, heating upgrades - typically cost more than a single measure taken in isolation; if you want a fuller sense of what a proper job costs across different property types and starting points, our whole-house retrofit cost guide breaks down realistic 2026 pricing so you can weigh the spend against the uplift figures above.
Why Period and Older Homes Are a Special Case
This is where the numbers above become genuinely relevant for a lot of UK homeowners, rather than a hypothetical. Properties built before 1919 are dramatically over-represented at the bottom of the EPC scale: roughly 24% of pre-1919 homes are still rated E, F or G, compared with just 2% of homes built after 1990. Solid brick walls, single glazing, suspended timber floors and a lack of cavity space all conspire to keep older housing stock rated D or below, often quite a long way below.
That means a large share of Victorian, Edwardian and Georgian homeowners are sitting exactly in the band where the research shows the biggest premiums apply - an E, F or G rating with a plausible route to C. If the Rightmove and Knight Frank figures hold for your property, the uplift from getting a genuinely poor-rated period home up to a C could plausibly sit in the high single digits to high teens as a percentage of value, not the 1-3% figure that gets quoted for a routine D-to-C move.
The catch, and it’s a real one, is that the retrofit itself is usually harder and more expensive for a period property. Solid walls generally need internal or external wall insulation rather than a simple cavity fill, listed status or conservation area rules can restrict what glazing or external changes are allowed, and getting the moisture management right on an older, more breathable building matters more than it does on a modern brick-and-block house. None of that changes the direction of the value data - it just means the cost side of the equation needs more care and a specialist who actually understands older buildings, not a generic installer. If you’re weighing this up for a period property specifically, our guide to insulating a period or Victorian home covers realistic solid-wall insulation costs and the trade-offs involved.
The Green Mortgage Angle: A Second, Separate Financial Lever
Resale premium isn’t the only financial mechanism at play - a growing number of UK mortgage lenders now offer better terms specifically tied to EPC rating, which is a distinct benefit from anything to do with eventual sale price. It matters for two reasons: it’s evidence that lenders themselves now treat energy rating as a credit-relevant factor, and it can put money back in your pocket well before you ever sell.
Examples of what’s currently on offer include:
- NatWest offers a reduced rate on selected 2-year and 5-year fixed green mortgages for properties with a valid EPC rating of A or B, with cashback options available too.
- Nationwide Building Society offers cashback on its own green mortgage range - £500 for an EPC score of 92 or above, or £250 for a score of 86-91 - roughly equivalent to the A/B bands.
- Barclays offers lower rates on some fixed-term mortgages for new-build properties with an EPC score of 81 or above, or an A/B rating.
- Kensington pays £1,000 cashback if you improve your EPC rating by one full band, or by 10 SAP points, within 12 months of completion - rewarding the act of retrofitting itself, not just the end state.
- Saffron Building Society reduces your rate by 0.10% if you improve your EPC rating within six months of taking out the mortgage.
These products are still a relatively small corner of the mortgage market, the discounts on offer are generally modest, and eligibility criteria (loan-to-value limits, property type, fixed-term length) vary by lender and change frequently, so treat any specific numbers here as illustrative rather than a live quote. But the direction of travel is clear: lenders increasingly see a well-rated home as a lower-risk asset, and are willing to price that in through cashback or a small rate reduction - a benefit that lands on remortgage as well as at resale.
Note the different flavours of reward here too. Some lenders, like NatWest, Nationwide and Barclays, only reward you once you’ve already reached an A or B rating - which won’t help most homeowners starting from a D, E or F. Others, like Kensington and Saffron, specifically reward the act of improving your rating within a set window after completion, regardless of your starting point. If you’re planning retrofit work around a remortgage date, it’s worth checking whether your lender falls into the second camp before you assume a green mortgage isn’t relevant to you.
The Honest Caveats: What the Data Doesn’t Support
It would be easy to string the figures above together into a case that retrofitting is a straightforward, near-guaranteed investment. The research doesn’t actually support that, and it’s worth being upfront about where the case is weaker than it first appears.
- There’s a gap between what people say and what they pay. Rightmove’s own survey found 94% of homeowners believe energy-efficient homes deserve a price premium, and separate research has found roughly three-quarters of homeowners share that belief. But the actual measured premium - 1.6% to 2.8% for an A/B-rated home over a D-rated one, according to Nationwide’s figures - is far smaller than that stated belief would suggest. Buyers say energy efficiency should matter more than it demonstrably does when the sale actually happens.
- Location, condition and affordability still dominate. Industry commentary accompanying this research consistently frames EPC rating as “one factor among many” in a purchase decision, well behind where a property is and what it’s realistically going to cost to buy in the first place. A brilliant EPC rating on a poorly-located or badly-maintained home won’t outweigh those bigger factors.
- Most people don’t retrofit for resale value, and that’s telling. In the same research, only around 22% of homeowners who’d made energy efficiency improvements said they’d done it to increase their property’s value, and just 7% did it specifically ahead of a sale. The overwhelming majority retrofitted to cut their bills or improve comfort - which is arguably a more honest way to frame the decision than treating it primarily as an investment.
- The buy-to-let premium is a different phenomenon. The much larger 12.2% premium seen for A/B-rated rental properties is best read as the market pricing in regulatory risk around future minimum EPC standards for rented homes, not straightforward buyer enthusiasm for efficiency. It doesn’t transfer directly to owner-occupied resale value.
- Cost is still the main barrier, and it’s a real one. Over half of homeowners who haven’t made improvements cite the up-front cost as the reason, according to the same body of research. The value uplift figures above need to be weighed honestly against what the work actually costs, not treated as free money.
None of this contradicts the headline finding - there is a genuine, research-backed price effect, and it’s larger for homes moving off a poor rating. It just means the honest framing is “a real but secondary financial benefit,” not “guaranteed return on investment.”
So Is It Worth It? Weighing Value Alongside Everything Else
Pulling this together: if your home is already a reasonable C or above, the research suggests you shouldn’t expect a large resale premium from pushing further up the scale - Nationwide’s data puts the gap between top and bottom-but-one bands at a few percentage points at most for owner-occupied homes. If your home is currently an E, F or G - which describes a lot of the UK’s older, solid-wall housing stock - the picture is more compelling: both Rightmove’s and Knight Frank’s research independently found uplifts in the high single digits to high teens as a percentage of value for getting a genuinely poor-rated home up to a C, alongside real ongoing bill savings in the hundreds of pounds a year.
Where that describes your situation, and especially where it’s a period property with the retrofit complexity that comes with solid walls and older construction, the value case is worth factoring in seriously - just not as the only reason to do the work, and not as a substitute for getting a proper, realistic quote first. Lower bills, a warmer and less draughty home, and a smaller carbon footprint are all reasons to retrofit in their own right; the resale and mortgage benefits are a genuine bonus on top, not the whole story.
If you’re trying to work out where your own property sits - what your current EPC rating means for your options, what a realistic retrofit would cost, and which local specialists actually have experience with homes like yours - that’s exactly what we help with.
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