Many high-rises in the UK are outdated, inefficient, and expensive to run. Demolition might sound like the only solution, but retrofitting can offer a better path forward, especially for heritage properties that are protected by law. But even in instances where preserving the nation’s history isn’t a consideration, retrofitting can provide a faster, more cost-effective solution.

Why Retrofitting Matters

The UK has some of the oldest buildings in Europe. Over a third of our buildings were built before 1946. Many of these structures lose heat quickly and rely on outdated gas heating. This leads to high carbon emissions and uncomfortable living conditions.

Retrofitting means upgrading systems and materials to meet modern standards. This might include better insulation, updated heating solutions, or smarter energy use. It helps buildings perform like new ones without the waste and cost of demolition.

What’s Involved in a Retrofit?

Retrofitting isn’t one-size-fits-all. It depends on the building’s age, structure, and location. Some retrofits are light-touch. Others are more complex. The two main types of improvements are:

• Passive upgrades – Focus on the building fabric, like insulation, windows, or draught-proofing.
• Active upgrades – Involve systems like heating, ventilation, and renewable energy.

Every project should start with a full assessment. You need to understand how the building performs today before deciding what to change. This often involves using energy modelling and carbon analysis to guide designs.

The Benefits of Retrofitting Older High-Rises

Environmental Benefits

Retrofitting helps buildings use less energy and produce fewer emissions. In some cases, energy use can drop by as much as 70%, which is a big step towards the UK’s net zero goals. It also avoids the high carbon cost that comes with knocking down buildings and starting again. By improving what we already have, we use less land and help protect green spaces from overdevelopment.

Economic Benefits

Retrofitted buildings are cheaper to run. Tenants save money on energy bills, and owners often see their property value go up. Offices and flats that have been upgraded are also easier to rent or sell.

In addition, retrofitting helps the economy. It creates jobs for planners, engineers, installers, and other skilled workers. If done on a large scale, it could lead to over 100,000 new jobs nationwide.

Social Benefits

Better insulation and heating make buildings more comfortable. That means fewer problems with damp, mould, and cold spots. For tenants, this can improve health and wellbeing.

Retrofitting can also help preserve the unique character of older buildings. Instead of replacing original features, the process focuses on improving energy performance in a way that respects the building’s design. This is especially important in historic or culturally significant areas, where architecture plays a key role in local identity.

Key Retrofit Solutions for Older High-Rise Buildings

Building Fabric Improvements

Upgrading the outer shell—or “fabric”—of a building is usually the first and most important step in a retrofit. This is because so much energy is lost through poorly insulated walls, windows, roofs and gaps. Here’s how each building is a part of:

Internal Wall Insulation

Older buildings often have solid walls with little or no insulation. Adding a thin layer of internal insulation helps keep the heat inside without damaging historic features. This is especially useful in listed or period buildings where changes to the outside walls aren’t allowed. It improves thermal comfort and reduces the need for constant heating.

Window Upgrades

Single-glazed or old wooden windows are major sources of heat loss and draughts. Installing secondary glazing (a second pane inside the existing frame) or replacing windows with modern, energy-efficient versions helps stop heat escaping and cuts down on cold spots. It also improves noise reduction and can make a space feel more secure.

Roof Insulation

A large amount of heat is lost through the roof, especially in high-rise buildings with exposed top floors. Adding or topping up insulation in the roof space helps trap warmth where needed. This is one of the most cost-effective ways to improve energy efficiency and can make upper-floor flats much more comfortable.

Draught-Proofing

Small gaps around doors, windows, and even floorboards can let in cold air and let warm air escape. Sealing these gaps with draught-proof strips, sealants, or under-door brushes makes a noticeable difference. It helps maintain a steady indoor temperature, reduces strain on heating systems, and improves comfort, especially during the colder months.

These changes make a big difference, even if they seem small.

Heating and Ventilation Systems

Older high-rise buildings often rely on outdated heating systems that are inefficient, expensive to run, and difficult to control. These systems also struggle to maintain consistent temperatures, leading to uncomfortable living or working conditions. Retrofitting offers a chance to replace these systems.

Here are some of the key upgrades we recommend:

Heat Pumps

• Heat pumps are one of the most efficient ways to heat a building. They extract heat from the air or ground and transfer it indoors. Even in cold weather, they can generate more energy than they use. For high-rise blocks, air source heat pumps are often easier to install, especially in communal systems serving multiple flats. Ground source pumps are highly efficient but require more space for underground pipework. When used correctly, however, heat pumps can dramatically cut carbon emissions and running costs.

Ventilation with Heat Recovery (MVHR)

• Many older buildings suffer from poor ventilation, leading to stale air, damp, and condensation. Simply opening windows lets out the heat along with the stale air. Mechanical Ventilation with Heat Recovery (MVHR) solves this by bringing in fresh air while capturing the heat from the outgoing air. It keeps rooms well ventilated without losing warmth, improving air quality and reducing energy waste, especially important in airtight buildings.

Zoned Heating Controls

• In older systems, heating is often all-or-nothing across large areas. Zoned controls allow different parts of the building, or even individual rooms, to be heated separately. This avoids wasted energy and lets occupants tailor their heating to their needs. For example, common areas can be heated less during off-peak hours, while living spaces stay warm and comfortable. This level of control not only improves comfort but also helps manage running costs more effectively.

These systems work best when paired with good insulation and air tightness.

Renewable Energy Options

Adding renewable energy systems to a retrofit can make the building even more efficient and sustainable. These systems create clean energy on-site, which reduces the need to buy electricity from the grid. If planning permission allows, there are several ways we can add renewable technology to older high-rise buildings. Here are some of the most common options:

Solar Panels

Solar panels can be placed on the roof or sometimes mounted on the side of a building (called a façade system). They turn sunlight into electricity, which the building can use straight away. In high-rise blocks, rooftops are often underused, making them a great place for solar. Even in cloudy weather, modern solar panels can still generate useful amounts of power.

Battery Storage

When solar panels generate more energy than the building uses, batteries can store the extra power for later. This is useful in the evenings or during poor weather. It also helps avoid sending energy back to the grid at times when it’s less valuable. Adding battery storage makes the most of the energy produced and adds stability to the building’s power use.

Smart Controls and Monitoring

Smart energy systems track how much energy the building has. They adjust heating, lighting, and other systems to run more efficiently. Occupants can see where energy is being used and make small changes that save money and cut waste. These systems are easy to use and offer real-time updates to help manage performance.

When roof space is tight, or the building has heritage restrictions, look for other ways to include renewables. This could include fitting panels on outbuildings, using shared systems for multiple blocks, or partnering with off-site renewable energy suppliers. The goal should always be to improve performance while keeping the building’s appearance and character intact.

Common Retrofit Challenges—and How to Solve Them

Technical Issues

High-rise buildings are complex. Access to façades, the weight of new systems, and fire safety standards all add pressure. But these challenges can be solved through careful planning.

Large projects should be broken down into smaller phases to help manage disruption and spread the cost over time.

Planning and Heritage Rules

Many older buildings are listed or in conservation areas. This limits what changes we can make, especially on the outside. By working with heritage consultants and local authorities early in the process you can often find ways to improve performance without changing the building’s appearance. And where the appearance does need to change, you’ve got buy-in from the right people from the start.

Funding and Return on Investment

Retrofitting is an investment. Upfront costs can be high. But the long-term gains are real—lower bills, higher asset value, better comfort.

There are grants and funding schemes available. These include the Boiler Upgrade Scheme and local council support. Make sure you explore all options to make the financial case clear.

Meeting Legal and Environmental Targets

Laws and building standards are changing quickly to support the UK’s net-zero goals. Building owners need to plan ahead to avoid fines, delays, or drops in property value. Retrofitting helps meet these rules, but it’s important to understand what’s required.

Here are some key regulations to be aware of:

• All commercial buildings must reach EPC rating B by 2030. An EPC (Energy Performance Certificate) shows how energy-efficient a building is. The rating goes from A (best) to G (worst). From 2030, most commercial properties will need to have at least a B rating to be let or sold. This means many older high-rise offices, shops, or mixed-use buildings will need upgrades, like better insulation, modern heating systems, or smart controls. Buildings that don’t meet the standard may lose value or become harder to rent out.
• Local plans, such as the London Plan, require developers to consider retrofitting first. In many cities, local councils now expect developers to explore whether a building can be retrofitted instead of knocked down. For example, the London Plan includes a rule that developers must carry out a Whole Life Carbon assessment before proposing demolition. This encourages the reuse of existing buildings, reducing embodied carbon (the carbon released when new materials are made and buildings are constructed).
• Listed buildings usually need full planning permission for external changes. If a building is listed or in a conservation area, you can’t make changes to its appearance without getting consent from the local planning authority. This includes things like changing windows, cladding walls, or adding solar panels.

The Future is Retrofit-First

The UK’s retrofit challenge is huge. Around 80% of the buildings we’ll use in 2050 already exist. Many of them will need upgrades if they’re to meet future needs.

At MosaicGT, we see this as a big opportunity. With the right approach, retrofitting can:

• Cut carbon
• Supthey’recal jobs
• Reduce fuel poverty
• Preserve heritage
• Improve living and working conditions.

New ideas and technologies are making retrofitting smarter and more flexible. For example, tools like Building Performance Evaluation (BPE) let us model a building’s energy use in detail. This helps us pick the best upgrades with the lowest risk.

Also, small changes—like improved air tightness or LED lighting—can sometimes deliver fast wins. In other cases, deeper work is needed.

Each building is different. That’s why you should take a tailored approach every time.

How MosaicGT can Support Your Retrofit Journey?

A retrofit only succeeds if its golden thread of information is complete, current and shareable. MosaicGT was built precisely for that job:

• Gateway-ready documentation – Drag-and-drop any drawing, certificate or test report into the platform and it’s instantly logged, version-controlled and queued for the correct BSA 2022 submission.
• Live project dashboard – See at a glance which packages are behind, which gateway evidence is missing and who’s on point to close the gap—before it hits the programme.
• Resident peace of mind – Our free iOS/Android app pushes evacuation plans and live service-certificate status straight to occupants’ phones, meeting the Act’s resident-engagement duty without extra site visits.

Ready to take the admin pain out of your high-rise retrofit? Book a 20-minute MosaicGT demo or email hello@mosaicgt.com—and let’s turn compliance into confidence.