A Shading Specifier’s Guide to Part L & O Compliance 2025

The UK’s commitment to reaching net-zero carbon emissions by 2050 has put the built environment under the spotlight – and for good reason.

Buildings are responsible for around 40% of the UK’s total carbon emissions. Rising energy costs, stricter regulations and the increasing frequency of summer heatwaves only add to the urgency.

It’s no longer enough to think about solar shading as an aesthetic extra or a nice-to-have. It’s becoming critical for hitting energy efficiency targets, slashing your building’s carbon footprint, and boosting climate resilience.

Without it, you risk falling behind on compliance and occupant satisfaction, while your operational costs keep climbing.

Why Solar Shading is No Longer Optional, But Essential

Solar shading is now firmly in the crosshairs of building performance and regulatory compliance.

New rules like Part L (focused on reducing CO₂ emissions) and Part O (targeting overheating risks) mean you’re expected to address solar gain head-on.

Shading also plays a powerful supporting role in achieving higher BREEAM ratings, enhancing sustainable architecture credentials and creating healthier, more comfortable spaces for people.

It’s about occupant well-being. It’s about smarter energy use. And ultimately, it’s about future-proofing your projects.

So, what exactly is solar shading?

At its core, it’s a passive design strategy. The goal is simple – control the amount of solar heat and natural light that enters a building.

Done right, shading drastically reduces the need for artificial cooling and lighting, which in turn cuts energy use and carbon emissions.

There’s a range of ways you can introduce shading into your designs, including:

• External louvres that block the sun’s heat before it hits glazing
• Brise-soleil architectural features that double as design elements
• External blinds and awnings for flexible sun protection
• Internal blinds (like roller or venetian blinds) offering user control
• Dynamic glass that automatically tints based on solar exposure

Each option offers varying levels of performance, aesthetic appeal and cost – and the right choice will depend on your project’s goals.

At Enviroscreen, we’re here to help you get it right.

We don’t just supply products – we work with you from the early design stages, advising on the most effective solar shading solutions based on your building type, orientation and regulatory requirements.

Whether you need external systems for maximum energy savings, internal blinds for ease of use, or a fully automated dynamic system, we’ve got the expertise to deliver a solution that ticks all the boxes: compliance, comfort, cost-efficiency and design integrity.

Decoding the UK Regulatory Landscape: Part L, Part O and Beyond

Understanding how building regulations are shifting is crucial if you want to deliver projects that stay compliant and energy efficient well into the future.

With pressure mounting to meet the UK’s net-zero 2050 goals, solar shading is becoming a quiet hero, woven into the fabric of evolving standards, even if it is not always shouted about.

Part L (Conservation of Fuel and Power): The Energy Efficiency Driver

Part L has always been about energy conservation, but the 2021 updates raised the bar significantly.

New homes must now achieve a 31 percent reduction in CO₂ emissions compared to 2013 standards. This tighter target is pushing architects and developers to look harder at passive design measures that ease the cooling and heating loads on a building.

Solar shading plays a vital, if often underappreciated, role here.

By controlling solar gain, you naturally reduce internal temperatures, cutting the reliance on mechanical cooling. This passive approach feeds directly into the energy performance calculations used in SAP for dwellings and SBEM for commercial buildings.

Part O (Overheating Mitigation): Bringing Shading into Focus

Part O is relatively new, introduced in 2022, and it puts overheating firmly on the agenda for residential developments.

Buildings must now pass an overheating risk assessment, using either a simplified method based on window sizes and shading, or dynamic thermal modelling according to the CIBSE TM59 guidance.

In both cases, solar shading becomes a critical tool. Especially in high-risk areas like dense urban centres or south- and west-facing buildings, passive shading solutions can be the difference between easy compliance and costly design revisions.

By reducing indoor temperatures and limiting solar gain, you can tick the Part O box confidently while also creating healthier, more comfortable spaces.

The Future Homes Standard 2025: Anticipating Stricter Requirements

The Future Homes Standard aims to slash carbon emissions from new homes by seventy-five to eighty percent compared to 2013 levels.

That is a huge jump, and it is clear that heavy reliance on mechanical systems alone will not be enough.

There is going to be a much stronger focus on the building fabric itself, and passive design strategies like solar shading are set to play a bigger role.

We are likely to see more explicit shading requirements emerge, as regulators push for homes that are zero carbon ready from day one.

If you are not already considering shading in your specifications, now is the time to get ahead.

Bridging the Gap: How UK Rules Compare to EU Counterparts

While the UK is moving in the right direction, it still trails behind other countries when it comes to solar shading regulations.

In Germany, the EnEV standards mandate shading solutions as part of their energy codes. France’s RT 2020 regulations also make solar control a requirement for compliance.

By contrast, UK rules remain more flexible, treating shading as a recommended measure rather than a mandatory one in most cases.

However, future updates could easily bring shading into the core compliance framework, mirroring our European neighbours.

Starting to design with this in mind is a smart move for long-term resilience.

Solar Shading & BREEAM: Elevating Sustainable Building Credentials

Sustainability is no longer just a marketing point; it is a major factor in how buildings are designed, valued and used.

If you want to deliver spaces that meet both today’s regulations and tomorrow’s expectations, understanding the role of solar shading in green building certifications like BREEAM is essential.

It’s about creating buildings that genuinely perform better for their occupants, the environment and their owners.

Understanding BREEAM’s Role in Sustainable UK Construction

BREEAM is the UK’s leading method for assessing the environmental performance of buildings.

It sets the benchmark for sustainable design and construction, and a strong BREEAM rating can significantly increase a property’s value, tenant appeal and long-term resilience.

Achieving certification proves that a building is energy efficient, health-conscious and future-ready.

In a market where ESG targets are increasingly non-negotiable, BREEAM is often the difference between a project getting greenlighted or passed over.

Solar shading is an often-underused lever within this system — but it can make a tangible difference to your final rating.

Key BREEAM Credits Where Solar Shading Makes a Difference

If you are aiming for higher BREEAM scores, solar shading can contribute directly in several key categories:

• Energy: Ene 01 – Reduction of energy use and carbon dioxide emissions Good shading design lowers cooling demand, helping to hit the energy targets BREEAM rewards.
• Health and Wellbeing: Hea 01 – Visual Comfort Effective shading reduces glare without sacrificing daylight, enhancing the visual comfort of occupants.
• Health and Wellbeing: Hea 04 – Thermal Comfort Shading helps maintain internal temperatures within comfortable ranges naturally, cutting the need for mechanical cooling.

By targeting these credits, you can drive up your sustainability rating while also improving the everyday experience for building users.

BREEAM Category	How Solar Shading Contributes
Ene 01 – Reduction of Energy Use and CO₂ Emissions	Lowers cooling loads, supporting better energy efficiency ratings
Hea 01 – Visual Comfort	Controls glare while allowing natural daylight, enhancing occupant well-being
Hea 04 – Thermal Comfort	Helps maintain comfortable indoor temperatures through passive design

Quantifying the Impact: Achieving Higher BREEAM Ratings (Up to 15% Uplift)

When applied strategically, solar shading can unlock a serious uplift in your BREEAM score — up to fifteen percent in some cases.

That is a major advantage in a competitive property market, especially as investors and tenants place greater value on verified sustainable performance.

Whether it is through passive design measures like external louvres or more advanced dynamic shading systems, investing in the right solution early can pay back not just in operational savings but in project prestige and long-term asset value.

The Tangible Benefits: Measuring the Impact of Solar Shading

Solar shading is not just a design decision; it is a measurable investment in a building’s long-term performance.

From cutting energy bills to improving occupant comfort, well-chosen shading strategies deliver real, tangible results that you can see on energy reports, feel in the indoor environment, and bank in operational savings.

Slashing Cooling Energy Demand: Significant Savings (25-40%)

Solar shading can cut cooling energy demand by between twenty-five and forty percent, depending on the type of system used.

External shading options, such as louvres and brise-soleil, are the most effective because they stop solar heat before it even reaches the glass.

Reducing solar gain in this way directly shrinks your building’s reliance on HVAC systems. Fewer demands on cooling mean lower running costs, smaller plant sizing and longer system lifespans.

It is passive cooling at its most efficient, helping you meet energy performance goals without overcomplicating your mechanical design.

Mitigating Overheating Risk: Creating Comfortable Indoor Environments

Heatwaves are becoming more common, and overheating is now a significant risk for many buildings.

Solar shading acts as a first line of defence, cutting internal temperatures and halving the number of overheating hours. That means better thermal comfort, improved productivity for occupants and an easier path to compliance with Part O regulations.

By preventing heat stress before it starts, shading turns spaces that might otherwise become unbearable into environments where people can thrive, even on the hottest summer days.

Optimising Daylighting: Balancing Light and Glare

One of the common myths about shading is that it blocks too much light.

In reality, a properly designed shading system manages natural light, allowing it to flood spaces without the problems of glare and overheating.

This balance means you can reduce the reliance on artificial lighting during daytime hours, improving visual comfort and cutting energy use even further.

Effective daylighting strategies, supported by shading, not only lower energy bills but also create healthier and more attractive working and living environments.

Reducing Carbon Footprint and Operational Costs

The energy savings from solar shading translate into serious environmental and financial benefits.

If solar shading were widely adopted, it could cut carbon emissions by up to one point two million tonnes every year across the UK.

Financially, the savings are equally compelling.

In commercial settings, external shading can reduce HVAC operating costs by up to twelve thousand pounds a year. Over the life of a building, this adds up to a significant return on what is a relatively modest upfront investment of around fifty to one hundred pounds per square metre.

With a typical payback period of seven to ten years, the lifecycle cost case for solar shading is difficult to ignore.

Impact Area	Solar Shading Benefit	Real-World Metrics
Cooling Energy Demand	25–40% reduction	Cuts cooling loads significantly
Overheating Risk	Up to 50% fewer overheating hours	Supports Part O compliance
Daylighting and Lighting Energy	Reduces glare, maximises natural light	Cuts artificial lighting needs
Carbon Footprint	1.2 million tonnes CO₂ saved annually (UK)	Major sustainability gain
Operational Costs	Up to £12,000/year HVAC savings	Typical payback in 7–10 years

Exploring Solar Shading Solutions: Types, Technologies and Materials

Choosing the right solar shading system is not a one-size-fits-all decision. Every project demands a solution that balances performance, aesthetics and budget.

The good news is, there is now a wide range of systems and materials available — each offering different strengths depending on the specific needs of your building.

Quick Decision Flow: Choosing the Right Solar Shading System

What is your top project priority?

⬇️

• Maximum energy efficiency and reduced cooling loads? ➔ Choose external shading systems (louvres, brise-soleil, external blinds)
• Lower upfront costs and strong aesthetic control? ➔ Choose internal shading systems (roller blinds, venetian blinds, curtains)
• Best internal performance without major cost increase? ➔ Choose cassette blinds with reflective fabrics
• Smart, automated building control and maximum occupant comfort? ➔ Choose dynamic and automated shading (automated blinds, smart glass)

Design Tip: For high-risk overheating areas or projects chasing higher BREEAM scores, combining external shading with smart internal systems delivers the best overall results.

Here is a closer look at the options.

External Shading Systems: Maximum Performance

External shading is often the first and most effective line of defence against solar heat gain.

By stopping the sun’s rays before they reach the glazing, external solutions offer the highest thermal efficiency.

Options include:

• Fixed or adjustable external louvres
• Architectural brise-soleil designs
• External roller blinds
• Retractable awnings for flexibility

While external systems deliver excellent energy savings, there are some trade-offs.

Higher upfront costs, aesthetic considerations for planning approval, wind load issues and long-term maintenance all need careful thought at the design stage.

But when performance matters most, external shading remains hard to beat.

Internal Shading Systems: Control and Aesthetics

Internal shading solutions sit inside the building envelope, offering a different set of advantages.

Popular choices include:

• Roller blinds in a variety of fabrics and styles
• Venetian blinds with adjustable slats for fine light control
• Curtains, including blackout and solar-reflective options

Internal systems are usually cheaper to install, easier to maintain and offer more user control. They can be beautifully integrated into interiors, supporting the aesthetic ambitions of the design team.

However, internal shading is less effective at reducing solar gain because the heat has already entered the building. In some cases, it can even trap heat between the glass and the shading device if not carefully specified.

If internal shading is the preferred route, the most efficient option is to use a cassette blind system combined with a high-performance reflective fabric.

This setup seals the blind closer to the glazing, reducing the amount of heat that leaks into the space while still allowing effective control over light and privacy.

Dynamic and Automated Shading: The Smart Approach

If you want to optimise performance without constant user intervention, dynamic shading is the way forward.

Automated blinds and louvres can respond to changing conditions, adjusting in real time based on solar radiation levels, indoor temperatures, occupancy patterns or Building Management System (BMS) commands.

Dynamic systems deliver maximum energy savings and occupant comfort, but they come with higher initial costs and greater complexity in design and commissioning.

Getting the integration right early on is critical for long-term success.

Integrated Façade Design: Shading as Architecture

Shading does not have to look like an add-on. It can be an integral part of your building’s identity.

Designing shading into the structure itself — through deep window reveals, architectural fins, overhangs, or bespoke façade treatments — delivers passive solar control while enhancing visual appeal.

This approach requires close collaboration between architects, engineers and shading specialists, but the results can be stunning both in terms of performance and aesthetics.

Material Matters: Durability, Performance and Aesthetics

The choice of materials has a huge impact on the performance and longevity of solar shading.

Common material options include:

• Powder-coated aluminium for durability and minimal maintenance
• Timber for a natural aesthetic (but with more maintenance requirements)
• High-performance fabrics with solar-reflective coatings
• Glass coatings such as low-e or spectrally selective films

When selecting materials, it is important to think about factors like solar absorptance, reflectivity, light transmission, colour stability and maintenance needs over time.

The right material can dramatically improve a shading system’s effectiveness — and the wrong choice can create costly problems down the line.

Putting Theory into Practice: Implementation and Best Practices

Choosing the right shading system is only half the story.

If you want to realise its full potential — in terms of energy savings, occupant comfort and compliance — you have to get the design, integration and execution right from day one.

This is where smart project planning and real collaboration make all the difference.

Early Stage Integration: The Foundation for Success

Solar shading decisions should not be an afterthought. The best results come when shading is considered at the very start of the design process.

Early integration allows you to optimise building orientation, window sizing and shading solutions together rather than trying to retrofit fixes later. It also ensures shading is properly factored into energy performance simulations like SAP or SBEM.

Tools like IESVE, EnergyPlus and Radiance can accurately model how shading will impact cooling loads, daylighting and overheating risk.

Running these simulations early gives you clear, data-driven guidance that improves decision-making and helps you stay ahead of regulatory demands.

Waiting too long means missed opportunities, higher costs and sometimes, suboptimal compromises.

Collaborative Design: Architects, Engineers and Specialists Working Together

Successful solar shading is never just about picking a product. It is about designing a system that fits seamlessly into the whole building strategy.

This requires real collaboration across the project team:

• Architects setting the overall vision and aesthetic
• Structural engineers ensuring shading structures are viable and resilient
• MEP engineers coordinating with cooling, ventilation and lighting systems
• Façade specialists helping to optimise thermal and visual performance

When these disciplines work together from the outset, shading becomes an integrated asset — not a bolt-on that causes problems later.

Good collaboration saves time, reduces errors and delivers much stronger building performance.

Common Pitfalls and How to Avoid Them

Even with the best intentions, shading strategies can fall short if you are not careful.

Some common traps include:

• Value engineering shading out of the design to save short-term costs, only to suffer long-term energy penalties and compliance issues
• Poor installation that leaves systems prone to malfunction, wind damage or reduced effectiveness
• Automated systems that users do not understand, leading to blinds being left permanently open or closed, undermining energy performance
• Neglecting maintenance, especially for external systems exposed to the elements, leading to failures just when shading is needed most

Avoiding these pitfalls starts with setting clear priorities early, specifying high-quality systems, training users properly and putting maintenance plans in place from day one.

5 Best Practices for Solar Shading Success

✅ Start Early

Integrate shading strategy at the concept design stage, not after planning.

✅ Model Performance

Use tools like IESVE, EnergyPlus or Radiance to simulate energy, daylight and overheating outcomes.

✅ Collaborate Across Teams

Architects, engineers and specialists should coordinate shading with cooling, lighting and ventilation systems.

✅ Specify for Longevity

Choose durable, high-performance materials suited to the building’s exposure and use case.

✅ Plan for User Training and Maintenance

Ensure automated systems are easy to operate, and build maintenance into the handover process.

The Horizon: Future Trends and Innovations in Solar Shading

Solar shading is not standing still.

New regulations, smarter technologies and evolving climate pressures are driving rapid innovation in the way we design, control and think about shading systems.

If you are planning buildings for the next decade and beyond, keeping an eye on these emerging trends will put you ahead of the curve.

Evolving Regulations: Towards Mandatory Shading?

There is growing momentum for solar shading to move from a recommended measure to a mandatory requirement in the UK building regulations.

Experts predict future updates to Part L and Part O will tighten the expectations around solar gain management, particularly for high-risk building types like residential blocks and care facilities.

Industry groups like the BBSA are actively lobbying for shading to be recognised as a core passive design strategy, not an optional extra.

The direction of travel is clear. Integrating shading now means you will be ready for future compliance instead of scrambling to retrofit solutions later.

The Rise of Smart and Predictive Shading Control

Technology is also reshaping what shading systems can do.

The next wave of innovation lies in smart shading that not only responds to real-time conditions, but predicts them.

Using IoT sensors, weather forecasting data, occupancy tracking and even dynamic energy pricing, future shading systems will be able to adjust proactively — optimising energy use, comfort and cost without human input.

AI-driven building control is no longer a futuristic concept. It is already starting to appear in cutting-edge office and residential projects, and it will soon be a standard expectation rather than a luxury.

Synergies with Renewable Energy: PV-Integrated Shading

Another exciting development is the merging of solar shading with renewable energy generation.

Building Integrated Photovoltaics (BIPV) allow shading elements like louvers, brise-soleil and façades to double as solar panels.

This creates a dual function — blocking unwanted heat gain while generating clean electricity at the same time. As the UK pushes harder on its renewable energy targets, PV-integrated shading will become an increasingly attractive option for forward-thinking developments.

It is an elegant way to maximise building performance without compromising on design.

Solar Shading’s Role in Enhancing Urban Climate Resilience

Wider adoption of solar shading has impacts that go beyond individual buildings.

By reducing solar gain across large numbers of properties, shading can significantly mitigate the urban heat island effect — where cities trap heat and become dangerously hotter than surrounding areas during heatwaves.

This not only protects occupant health and comfort but also reduces strain on energy grids, lowering the risk of brownouts and blackouts.

Some studies suggest that by 2050, widespread solar shading could prevent up to £1.2 billion per year in overheating-related losses to the UK economy.

It is a small intervention with huge potential to support climate adaptation and urban resilience strategies.

Actionable Recommendations for Key Stakeholders

Knowing the benefits of solar shading is one thing — but putting the right steps into action is where real progress happens.

Whether you are designing new buildings, managing developments or shaping the rules, there are practical moves you can take today to future-proof projects and drive better outcomes.

For Architects and Designers

• Prioritise solar shading from the earliest design stages, not after planning approval.
• Use building performance simulation tools like IESVE, EnergyPlus and Radiance to test and optimise shading strategies.
• Select shading systems and materials that are tailored to your building’s orientation, climate exposure and intended use.
• Collaborate closely with structural engineers, MEP consultants and façade specialists to integrate shading seamlessly into the overall design.

Good shading does not compromise the architecture. Done well, it elevates it.

For Developers and Building Owners

• View solar shading as an investment in long-term value, not just an upfront cost.
• Focus on lifecycle cost analysis — factoring in energy savings, reduced HVAC system sizing, higher asset ratings and improved tenant appeal.
• Explore retrofitting shading to existing buildings, especially in high-risk overheating areas.
• Ensure shading systems are properly commissioned and that building users are trained to operate them for maximum benefit.

Every pound invested in smart shading pays dividends in reduced operating costs and enhanced building performance.

For Policymakers

• Strengthen the requirements for solar shading within future updates of Part L and Part O, making it a more explicit element of compliance.
• Introduce financial incentives, grants or tax relief schemes to encourage the retrofitting of shading systems, particularly in urban centres.
• Support the development of clearer standards and guidelines through organisations like BSI to make best practices easier to adopt across the industry.
• Promote industry-wide training initiatives to raise awareness and build capability around passive cooling and solar shading design.

Effective policy support could unlock huge gains in energy efficiency, occupant comfort and urban resilience — without major new technology or infrastructure.

Conclusion: Embracing Solar Shading for a Sustainable & Compliant Future

Solar shading is no longer just a design choice — it is a fundamental part of building sustainable, resilient and compliant spaces in the UK.

With rising energy costs, tougher regulations and increasing risks from overheating, shading offers a practical, proven way to reduce carbon footprints, cut operational costs and create healthier environments for people.

Throughout this article, we have seen how the right shading strategy can:

• Slash cooling energy demand by up to 40 percent
• Improve occupant comfort and reduce overheating risks
• Boost BREEAM scores and asset value
• Support long-term resilience against climate change
• Deliver strong returns on investment through lifecycle savings

Whether through external louvres, internal cassette blinds, dynamic smart systems or integrated architectural solutions, shading is one of the smartest moves you can make to future-proof your projects.

At Enviroscreen, we help you make that happen.

From early-stage advice and modelling support to supply, installation and aftercare, we work with architects, developers and building owners to deliver shading solutions that balance performance, compliance and design.

Our team brings the technical expertise and practical experience you need to get it right, first time.

Start planning your shading strategy today — and build spaces that are not just compliant, but genuinely built for the future.

Frequently Asked Questions (FAQ) about Solar Shading in the UK

Is solar shading mandatory under UK building regulations?

Solar shading is not explicitly mandatory across all projects, but it is becoming increasingly essential. For residential developments, shading is a key strategy for complying with Part O, which addresses overheating risks. It also supports meeting energy efficiency targets under Part L by reducing cooling loads.

How much does solar shading typically cost?

Costs vary depending on the system type, level of automation, and project complexity. As a rough guide, expect between £50 and £100 per square metre for quality shading solutions. Higher-end dynamic or smart systems can be more expensive but offer greater long-term savings and control.

What is the most effective type of solar shading?

External shading systems — such as louvres, brise-soleil and external blinds — usually deliver the best thermal performance. They block solar heat before it reaches the building envelope, offering superior energy savings compared to internal solutions.

Will solar shading make my building too dark?

Properly designed solar shading should not make interiors gloomy. The aim is to manage daylight intelligently, reducing glare and solar heat gain while still allowing useful natural light to enter. Techniques like adjustable louvres, selective fabric choices and dynamic systems help achieve this balance.

Can solar shading be retrofitted to existing buildings?

Yes. There are a wide range of retrofit solutions available, including external systems, internal cassette blinds with reflective fabrics and even dynamic glass options. Retrofitting shading is a highly effective way to enhance energy performance, especially in older or overheating-prone buildings.