How to Make a Listed Building More Energy Efficient

This article was published on September 25, 2026

Making a listed building more energy efficient can be challenging. Older properties were built using traditional materials and construction methods that are very different from modern homes, while original windows, doors and other features may be protected because of their historic importance.

However, being a listed building doesn’t mean you have to accept draughts, heat loss and high energy bills.

There are several ways to improve the energy efficiency of a listed property while taking a sympathetic approach to its original character. From sash window refurbishment and draught proofing to secondary glazing and specialist glazing, relatively targeted improvements can make a noticeable difference.

Why Are Listed Buildings Difficult to Make Energy Efficient?

Traditional buildings often have features that don’t perform in the same way as modern construction.

Single-glazed timber windows, gaps around old frames, poorly fitting doors and ageing glazing can all contribute to heat loss. At the same time, replacing these features with modern alternatives may not be appropriate for a listed building.

The challenge is therefore to improve performance without unnecessarily removing or altering historic fabric.

Before making changes, it’s important to understand which parts of your property are protected and whether consent is required for the proposed work.

Start With Your Windows

Windows are often one of the most obvious sources of heat loss in an older property.

If your listed building has original timber sash or casement windows, completely replacing them may not be the best solution. In many cases, existing windows can be repaired and upgraded to improve their performance while retaining their historic appearance.

Sash Window Refurbishment

Traditional sash windows can often be refurbished rather than replaced.

A professional refurbishment can address:

• Rotten or damaged timber
• Broken sash cords
• Poorly fitting sashes
• Draughts and rattles
• Damaged glazing
• Worn pulleys and hardware

Once repaired, discreet draught-proofing and glazing improvements can further enhance performance.

This approach allows you to retain original windows while making them more comfortable and efficient.

Draught Proofing

Draughts can have a significant impact on the comfort of a traditional property.

Over time, timber frames can develop gaps around moving parts and joints. These gaps allow cold air into the property and warm air to escape.

Professional draught proofing can reduce unwanted air movement around existing windows without changing their external appearance.

For traditional sash windows, discreet draught-proofing systems can be incorporated into the window while retaining the original style and operation.

Consider Secondary Glazing

Secondary glazing can be an effective solution where replacing the original windows isn’t desirable or permitted.

Rather than removing the existing window, a separate glazed unit is installed on the inside of the frame. This creates an additional insulating layer while leaving the original external window intact.

As well as helping to reduce heat loss, secondary glazing can provide significant improvements in acoustic insulation, making it particularly useful for listed properties in busy urban areas.

It can also be designed to be discreet, helping preserve the appearance of the original windows.

Upgrade the Glazing

If your existing windows need more than draught proofing, specialist glazing may provide another option.

Traditional window frames can present challenges for standard modern double glazing because thicker glass units can change the appearance and proportions of the window.

Slim double glazing and vacuum glazing offer alternatives where maintaining traditional sightlines is important.

Vacuum glazing uses a very thin gap between panes to provide high levels of thermal insulation without requiring the same thickness as conventional double glazing.

The suitability of any glazing upgrade will depend on the existing window, its condition and the requirements of the building.

Don’t Forget Your Doors

Windows aren’t the only source of heat loss.

Traditional external doors can also allow significant amounts of cold air into a property, particularly where they have gaps around the frame or have deteriorated over time.

Repairing timber doors, improving seals and ensuring they close correctly can help reduce draughts without changing their appearance.

Where replacement is necessary, a bespoke timber door can be designed to replicate traditional proportions and detailing while incorporating modern security and thermal performance.

Improve Energy Efficiency Without Losing Character

For a listed building, energy efficiency shouldn’t necessarily mean replacing every traditional feature with a modern equivalent.

In many cases, a combination of smaller improvements can deliver better results while retaining the property’s character.

For example, a traditional sash window might benefit from:

Timber repairs → Draught proofing → Specialist glazing → Improved ironmongery

Together, these measures can significantly improve comfort and performance without fundamentally changing the appearance of the window.

Can You Double Glaze a Listed Building?

It may be possible to introduce double glazing to a listed building, but this depends on the property, the existing windows and the proposed design.

Standard double glazing can be unsuitable for some historic windows because of the thickness of the glazing units and the effect this can have on traditional sightlines.

Slimline or specialist glazing may provide a more sympathetic alternative. In other situations, secondary glazing can improve thermal performance while allowing the original windows to remain untouched.

If your property is listed, you should establish whether listed building consent is required before making alterations to historic windows or doors.

What About Listed Building Consent?

Listed buildings receive special protection because of their architectural or historic interest.

This doesn’t mean that improvements are impossible, but alterations that affect the building’s special character may require consent.

Before carrying out work, consider:

• Whether the windows or doors are original
• Whether the proposed work changes their appearance
• Whether historic materials will be removed
• Whether the work can be carried out through repair or refurbishment
• Whether listed building consent is required

If you’re unsure, your local planning authority or conservation officer can advise on the requirements for your property.

Which Improvements Should You Consider First?

Every listed building is different, so there isn’t one solution that works for every property.

However, a sensible approach is to start by assessing the existing building and identifying where the biggest improvements can be made.

For windows and doors, this could mean:

1. Repairing damaged timber
2. Improving draught proofing
3. Upgrading glazing where appropriate
4. Installing secondary glazing
5. Improving seals and ironmongery
6. Replacing windows or doors only where necessary

Taking this approach can help improve energy efficiency while retaining as much original fabric as possible.

Improving Listed Buildings With ERW

ERW has been manufacturing, repairing and restoring timber windows and doors since 1979, with extensive experience working on listed buildings and period properties.

Our services include sash window refurbishment, timber repairs, draught proofing, secondary glazing and specialist glazing solutions. Where replacement is appropriate, we can also manufacture bespoke timber windows and doors designed to complement the character of the property.

The most energy-efficient solution isn’t always to replace an original window. In many cases, careful repair and targeted upgrades can provide an effective balance between energy efficiency, comfort and heritage preservation.

If you’re looking to make a listed building warmer and more energy efficient, assessing your existing windows and doors is a good place to start.