There is near-universal agreement that homes should be warmer, healthier, and cheaper to run. Few people seriously argue against improving the energy efficiency of rental properties.
The difficulty is not the direction of travel.
It is the assumption that this journey is simpler, cheaper, and more predictable than it really is.
Recent changes to EPC legislation, and the expectation that the private rented sector (PRS) should meet EPC Band C, bring that tension into sharp focus. This article looks not at what the policy intends, but at what is likely to happen in practice, once real buildings, real tenancies, and real economics are involved.
When a measurement becomes the mission
EPCs are persuasive because they produce a number. Numbers feel objective. They imply control.
But EPCs are not measurements of lived experience. They are models, built on assumptions about construction type, heating use, ventilation, and occupant behaviour. They estimate performance rather than observe it.
The risk is that when a number becomes the target, behaviour shifts toward improving the number rather than the outcome. This is a well-known behavioural trap. People optimise for what is measured, even when it only loosely reflects what we actually care about.
In housing terms, that can mean compliance without comfort, and efficiency on paper that does not translate into healthier homes.
The £10,000 cap: reasonable to policymakers, existential to others
A £10,000 cost cap sounds sensible. It signals restraint. It reassures decision-makers that landlords are not being asked to do the impossible.
But the same figure feels radically different depending on who you are.
For a large landlord or institutional operator, £10,000 is a manageable capital decision. It can be spread across a portfolio, financed cheaply, and planned strategically.
For a small landlord, often with one or two properties and gross rental income of £9,000 to £12,000 per year, £10,000 can represent a full year’s income, a personal financial risk, and a source of genuine anxiety.
The rule is uniform. The impact is not.
What retrofitting actually involves
I have had to work through these upgrade decisions myself, not in theory but on the ground, speaking with heating engineers, roofers, insulation installers, and homeowners who already have solar panels.
The reality looks like this.
Internal wall insulation
For many older properties and flats, internal insulation is the only viable option. Done properly, it is expensive, disruptive, and space-reducing. Once materials, vapour control layers, electrical alterations, plastering, and redecoration are included, costs escalate quickly.
It is also extremely difficult to carry out with tenants in situ.
External wall insulation
External wall insulation is often presented as a clean solution, but long-term performance is mixed. Poor detailing can allow water to track behind the system, trap moisture, and create hidden damp problems. Industry experience increasingly suggests that failures are not rare; they are simply slow to reveal themselves.
Heat pumps
Heat pumps are improving and grant support exists, including for landlords. However, they work best in well-insulated homes with low-temperature heating systems.
In flats, particularly upper-floor flats, installation is often impractical or impossible due to limited external wall space, noise and planning constraints, communal ownership issues, and complex pipe and condensate runs.
Even where installation is technically possible, expectations around heat response and hot water often clash with tenant experience.
Solar panels: then and now
It is worth remembering why solar took off originally. Under the old Feed-in Tariff regime, households were paid far more per kilowatt-hour for generated electricity than they could buy it for from the grid. There were even schemes where panels were installed for free in return for the tariff income.
That incentive no longer exists.
Today, electricity prices are high, often around 40 to 45 pence per kilowatt-hour, while export payments for surplus solar generation are typically around 4 to 6 pence. The financial logic has inverted. Solar now primarily benefits the occupier by offsetting expensive electricity, rather than providing a meaningful income stream for the property owner.
EPC modelling often assumes energy prices and behaviours that no longer reflect reality. That said, where a property is already due a new roof, combining roof replacement with solar installation can make sense, limiting disruption and helping achieve the required EPC rating.
Electricity, gas, and distorted assumptions
Electricity remains significantly more expensive per unit than gas. This undermines some of the assumed savings from electrification, particularly for heat pumps in marginal stock.
On paper, heat pumps look compelling. In practice, high electricity costs can make running costs unpredictable, especially where insulation or system design is sub-optimal. Heat pumps also perform best with underfloor heating, which in most existing homes would require lifting all flooring and adding further cost and disruption.
This is not an argument against electrification. It is a reminder that price signals matter, and current ones complicate the picture.
Retrofit knowledge gaps and unintended harm
Large-scale domestic retrofitting is relatively new in the UK. We do not yet have decades of evidence on how different systems interact in older housing stock.
Insulation installed without sufficient ventilation, or without a proper understanding of moisture movement, can shift dew points and increase condensation risk. Mould can develop behind insulation layers, unseen until it becomes severe.
This is where EPC legislation begins to collide with Awaab’s Law.
A policy designed to reduce cold and damp risks may, if implemented poorly, create new mould problems, with tenants understandably attributing responsibility to landlords. The line between structural failure and occupant behaviour becomes harder to evidence, not easier.
Reno-evictions: the problem nobody wants to name
Many EPC-driven upgrades are not minor works. Internal insulation, major heating changes, and roof upgrades often require vacant possession.
At the same time, tenancy reform is moving toward making possession harder to obtain.
This creates a pressure point. Landlords may feel forced to recover possession in order to comply. Even where done lawfully, this risks increasing so-called “reno-evictions”, particularly in lower-value stock where the economics are tightest.
That outcome helps no one.
Is the private sector being asked to do more than social housing?
It is a fair question.
The private rented sector is being asked to meet EPC Band C on a defined timeline, with capped spend and limited access to grants. Meanwhile, much of the social housing sector, with greater capital support, longer planning horizons, and fewer barriers to disruptive works, is progressing more slowly through similar challenges.
This is not about lowering standards in the PRS.
It is about whether expectations align with delivery capacity across tenures.
Uniform rules do not produce uniform outcomes. It is reasonable to ask whether the social housing sector itself can currently achieve the standards being imposed on the PRS.
Behaviour under pressure: leaning on the EPC score
As compliance pressure increases, so does the temptation to lean on the metric.
There is a growing risk that EPC assessors, particularly where assessments are commissioned in-house, face subtle pressure to “find” a Band C. When the difference between legal letting and prohibition comes down to a handful of points, incentives become distorted.
This undermines confidence in the system and shifts focus away from genuine building performance.
Affordability and the people at the sharp end
It is worth remembering why people rent. Often, it is because they cannot afford to buy.
At the lower end of the market, where properties are older, margins are thinner, and upgrades least likely to stack up, the risk is that costs are passed on, supply contracts, or landlords exit altogether.
Ironically, this can make the rental market less affordable for the most vulnerable, precisely the group these reforms are intended to help.
Evidence will matter more than ever
As standards rise, disputes will increase. Mould, condensation, heating performance, and responsibility will all come under greater scrutiny.
EPC ratings will increasingly be cited as proof of adequacy, even where real-world conditions are more complex. This makes independent, detailed inventories and inspections critical. Good evidence does not assign blame. It records reality.
Final thought: don’t confuse compliance with success
Improving the energy efficiency of homes is the right goal. But homes are lived in, not modelled.
The real risk is not that we aim too high, but that we mistake numerical compliance for meaningful improvement, and create new problems while trying to solve old ones.
If EPC reform is to succeed, it must acknowledge complexity, respect behavioural reality, and recognise that how we improve homes matters just as much as the targets we set.
