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New 2026 rental regulations require minimum EPC ratings. Learn how secondary glazing can improve your property's energy efficiency without replacing original windows.
If you're a landlord with period properties in London, the clock is ticking. New energy efficiency regulations coming into force in 2026 will require rental properties to meet minimum EPC (Energy Performance Certificate) standards—and windows are often the biggest obstacle to compliance.
For owners of listed buildings and properties in conservation areas, the challenge is particularly acute. You can't simply rip out your Georgian sash windows and install UPVC double glazing. So what are your options?
From 2026, all rental properties in England and Wales will need to achieve a minimum EPC rating of C for new tenancies, with existing tenancies following by 2028. Properties that don't meet this standard cannot legally be let.
Currently, around 60% of English homes have an EPC rating of D or below. Period properties with single-glazed windows are particularly affected—many sit at E, F, or even G ratings.
The penalties for non-compliance are significant: fines of up to £30,000 for letting a property below the minimum standard.
Windows are one of the largest contributors to heat loss in any building. In a typical period property:
An EPC assessor will specifically examine your glazing type, frame material, and window area. Single glazing with timber frames scores poorly; double glazing scores well. But what if you can't install double glazing?
Here's the good news: secondary glazing is recognised by EPC assessors as an energy efficiency improvement. When properly installed, it can:
For a property currently rated D (score 55-68), good-quality secondary glazing combined with other improvements can often push it into the C band (score 69-80).
There's an important exemption that many landlords don't know about. Properties where energy efficiency improvements would "unacceptably alter the character or appearance" of a listed building or building in a conservation area may qualify for an exemption.
However, this exemption requires you to demonstrate that you've explored all reasonable alternatives. Installing secondary glazing shows you've taken action to improve efficiency while respecting heritage constraints—strengthening any exemption application.
In practice, secondary glazing often negates the need for an exemption entirely by achievin
For expert secondary glazing advice and free consultations for listed buildings in London, contact Secondary Glazing Specialist on 020 7060 1572.
James Whitfield
Conservation Planning Advisor
If you're a landlord with period properties in London, the clock is ticking. New energy efficiency regulations coming into force in 2026 will require rental properties to meet minimum EPC (Energy Performance Certificate) standards—and windows are often the biggest obstacle to compliance.
For owners of listed buildings and properties in conservation areas, the challenge is particularly acute. You can't simply rip out your Georgian sash windows and install UPVC double glazing. So what are your options?
From 2026, all rental properties in England and Wales will need to achieve a minimum EPC rating of C for new tenancies, with existing tenancies following by 2028. Properties that don't meet this standard cannot legally be let.
Currently, around 60% of English homes have an EPC rating of D or below. Period properties with single-glazed windows are particularly affected—many sit at E, F, or even G ratings.
The penalties for non-compliance are significant: fines of up to £30,000 for letting a property below the minimum standard.
Windows are one of the largest contributors to heat loss in any building. In a typical period property:
An EPC assessor will specifically examine your glazing type, frame material, and window area. Single glazing with timber frames scores poorly; double glazing scores well. But what if you can't install double glazing?
Here's the good news: secondary glazing is recognised by EPC assessors as an energy efficiency improvement. When properly installed, it can:
For a property currently rated D (score 55-68), good-quality secondary glazing combined with other improvements can often push it into the C band (score 69-80).
There's an important exemption that many landlords don't know about. Properties where energy efficiency improvements would "unacceptably alter the character or appearance" of a listed building or building in a conservation area may qualify for an exemption.
However, this exemption requires you to demonstrate that you've explored all reasonable alternatives. Installing secondary glazing shows you've taken action to improve efficiency while respecting heritage constraints—strengthening any exemption application.
In practice, secondary glazing often negates the need for an exemption entirely by achieving sufficient EPC improvement.
When an EPC assessor visits your property, they'll examine:
Secondary glazing ticks multiple boxes: it counts as an additional glazing layer, and properly installed units eliminate draughts completely.
Not all secondary glazing will deliver the same EPC improvement. For maximum benefit:
Cheap magnetic or removable secondary glazing may not deliver the same benefits as professionally installed units with proper sealing.
Let's be practical about the numbers:
For a typical London flat with 6-8 windows:
The investment in secondary glazing pays for itself many times over compared to the cost of non-compliance.
Beyond EPC compliance, secondary glazing offers landlords several advantages:
If you're a landlord with period properties, now is the time to act. The 2026 deadline is approaching fast, and installation schedules fill up quickly as demand increases.
We recommend:
Our team has extensive experience helping landlords achieve EPC compliance while preserving heritage features. Call 020 7060 1572 to discuss your portfolio.
London's leading secondary glazing specialists for Grade I, Grade II, and Conservation Area properties. Every project begins with a complimentary heritage survey.
