Renewable technology in sustainable builds: Everything you need to know about solar power

Farhan Ganam

In the pursuit of sustainable development, architects, builders, and homeowners alike are increasingly turning to solar power as a key component of sustainable building practices. One would think solar energy is all about harnessing sunlight and turning into electricity. However, what happens behind this process is something some of us might not be aware of. Let's take a deep dive into understanding the incredible potential of solar power.

An introduction to solar

The concept of solar energy dates back to ancient civilization, where people would use magnifying glasses to focus the sun's rays to create fire. Fast forwarding to the 19th century, solar power's true inception began when French physicist Alexandre Edmond Becquerel made a staggering discovery on how sunlight can be used by certain materials to generate electricity. The popularity of solar power has been growing due to the fact that harnessing the sun's power for generating electricity is one of the most environmentally friendly processes out there.


The two main technologies that harness the sun’s power are heat and electricity. These are known as solar heat and solar power:

  • Solar heat is a process where sunlight is used for heating water in domestic and commercial buildings. This technology is more popular in areas where there is high concentration on solar radiation. 
  • However, when it comes to countries like the UK which aren’t always so sunny, solar power is a widely preferred option. Solar power is all about how electricity can be generated by using the contact of sunlight on a material. Let’s take a closer look at solar power to understand it better.


How does solar power work?

To keep it simple, you’ll generate electricity when the electrons of the atom flow from positive to the negative terminal of the element. When Becquerel discovered how an element can use sun energy to produce electricity, the term “photovoltaic effect” was coined. Through the photovoltaic effect, electricity generation largely relies on one element, namely silicon. The main purpose of using silicon is because it's a semiconductor. 


What this means is, if you combine them with different materials, the semiconductor can easily change its atomic properties. This process of combining is also known as ‘doping’.


Regarding silicon, this is done by:

  1. Adding boron, which makes silicon negatively charged; and 
  2. by adding phosphorus, making it positively charged. 


In ‘solar terms’, these are known as n-type and p-type junctions. 


Solar panels on a brick house roof under a cloudy sky.

When p-type and n-type materials are sandwiched together, they create something called a ‘solar cell’. When these junctions are combined, they seldom do anything other than transfer electrons in themselves. 


However, the magic happens when sunlight hits this material. The energy of photons in sunlight makes electrons flow from n-type to p-type, due to the former being negatively charged and later being positively charged. 


This transfer occurs near contact and makes the center region eventually stable. The stable state restricts the flow of electrons and thus creates what is known as the ‘depletion zone’. This zone acts as a barrier between the n-type and p-type junction contact and hence the flow of electron stops. 


However, imagine what happens if you use a circuit that connects both n-type and p-type externally? The electron starts to flow again. 


Now this electron flow is exactly how electricity is generated through photovoltaic effect. Fascinating, isn’t it?


The different types of solar panels

Person in a black shirt holding a solar panel on a tiled roof, wearing yellow gloves.

When a group of solar cells are combined together, they’re known as solar panels or solar photovoltaic (PV) panels. Solar panels come in various sizes and types. These sizes reflect the power one solar panel can deliver. With how technology has evolved, there are currently 4 types of solar power technologies:


Crystalline silicon - This type of technology is the first generation of solar panels, working on the basic principle of solar electricity generation explained earlier.
This type of panel is further categorised into two types:

  • Polycrystalline - which are made from fragments of silicon; and
  • Monocrystalline - made from single crystal silicon. 


The key difference is the efficiency each one gives. Most commercially available polycrystalline PV has an efficiency ranging from 17-18% and has capacity between 50 kWp to 350 kWp. However, monocrystalline PV efficiency often goes up to 22% efficiency with capacity of up to 530 kWp. In the UK, monocrystalline is preferred due to its efficiency and high capacity.


Thin-film solar technology - This type of solar panel is constructed using thin layers of semiconductor materials like cadmium telluride (CdTe), copper indium gallium selenide (CIGS), or amorphous silicon (a-Si). The key difference between this panel and crystalline silicon type is the flexible nature and the possibility of integration into curved or irregular surfaces. Thin-film performs better in low-light conditions and has a lower temperature coefficient, meaning it can maintain higher energy production in hot climates. However, the overall efficiency falls between 9-15% which restricts its commercial use.


Dye cell technology - This type of cell is also a type of thin-film with a key difference that it uses dye as the light absorbing material. It consists of several layers including semiconductor material (typically titanium dioxide), electrolyte and electrodes. The dye molecule in the semiconductor layers captures photons from sunlight and transfers the absorbed energy to semiconductor generating electric current. One of the advantages of dye cells is their ability to capture a broad range of the solar spectrum, including visible and infrared light, making them more efficient in low-light conditions compared to other solar cell technologies. The efficiency lies between 4-10%.


Perovskite solar technology - This type of solar cell utilises perovskite material such as methylammonium lead iodide (MAPbI3) as the light absorbing layer. One of the key advantages of perovskite solar cells is its high power conversion efficiency potential. They’ve even surpassed the efficiency levels of traditional silicon based solar cells in a relatively short period. Their efficiency has reached up to 30%. The key disadvantage of why the panels are not commercially used is the fact that their life span is only about 5 years compared to 20 - 25 years for silicon based solar cells.


Is the UK climate suitable for solar installation on a small residential or large commercial/industrial scale?

Despite its reputation for overcast and rainy weather, the UK's climate is definitely suitable for solar installation. While the amount of sunlight received might be less compared to sunnier regions, solar panels can still generate large amounts of electricity. Typically, monocrystalline solar panels are considered to be the most preferred due to their high capacity and efficiency. 


  • On a small residential scale, solar panels can be installed on rooftops to generate electricity for homes. The electricity generated can be used to power household appliances and reduce reliance on the grid, leading to potential cost savings and a lower carbon footprint. 
  • For large commercial and industrial installations, solar panels can be deployed on rooftops, open land, or even integrated into the design of buildings. These installations can help meet the energy needs of businesses, reduce electricity costs, and contribute to sustainability goals.


It’s important to consider factors such as available space, orientation, shading, and the specific location when planning solar installations in the UK. Conducting a site assessment and consulting with solar experts can help determine the feasibility and optimise the performance of solar systems based on the unique characteristics of each location.


How does a solar rooftop system work?

Person installing solar panel on a rooftop against a clear blue sky.

A typical solar rooftop has 3 main components:

  1. solar panels
  2. an inverter 
  3. a bi-directional meter


When electricity is generated through solar panels, the DC current is supplied from solar panels through the circuit to the inverter. The function of an inverter is that it converts the DC into AC, which is what your home requires. 


After this conversion, the AC goes into the bi-directional meter, where electricity is supplied to appliances or gets exported to the grid if there is excess. The meter also helps in making sure that the electricity supply is not interrupted even when the solar rooftop system is not generating at night.

How much does a solar rooftop system cost and what is the expected payback?

The cost of a solar rooftop system depends on different factors, including size of the system, type of the panels and components used, and the complexity of installation. In the UK, the average cost of a solar rooftop system is around £4,000 to £8,000 per kilowatt (kW) of installed capacity. Therefore, a 5 kW solar system would cost around £20,000 to £40,000.


It’s worth noting that for the solar system to pay for itself, it all depends on factors like upfront cost, the electricity rates, the system's energy generation, and any financial incentives. On an average, it takes around 8 to 10 years for payback on systems installed in the UK.


Are there any financial incentives or schemes from the government?

As of today, there are two main schemes backed by the UK government to support installation of solar rooftop systems. The 0% VAT on energy-saving products & Smart Export Guarantee (SEG).

  1. 0% VAT - In March 2022, Chancellor Rishi Sunak, now the Prime Minister of the UK, announced that the VAT for energy saving products such as solar panels & heat pumps will go down from 5% to 0%. According to the UK Government, this reduction allows for savings of about £1,000 in installation and about £300 in operating cost. This scheme is planned to end in March 2027. For more details, you can go through the government's website.
  2. Smart Export Guarantee (SEG) - The SEG came into effect in January 2020. The key advantage of this scheme is that for any small scale electricity generator, the owner can get payments from the grid to export any surplus energy. This scheme adds the obligation of grip suppliers to offer export tariff rates to their customers. Typically, the rates range from 1p and 7.5p per kWh. It should be noted that in order to qualify for this scheme, the homeowner must install a bi-directional meter to allow the import and export of electricity.


How can Mesh help?

Mesh energy provides consultation and designing solutions for installing solar rooftop systems in both residential and commercial property. It’s part of our feasibility study where we look into various renewable energy options to explore how it can affect the efficiency of the overall house both environmentally and economically. At Mesh, we believe in a fabric-first approach and examining various construction options that promote sustainability. This way, we make sure the building energy demand is minimal, which in turn helps in reducing the size of renewable systems such as heat pumps and solar rooftop systems. To talk more about installing a system for your project, get in touch today.


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9 March 2026
Energy performance specialist Mesh has successfully delivered a sustainability project for Forestry England at Westonbirt, The National Arboretum, helping to improve the energy efficiency and long-term resilience of buildings on the 600-acre estate. The historic arboretum near Tetbury, managed by Forestry England, is one of the UK’s most visited heritage sites, attracting hundreds of thousands of visitors every year. Rapid growth in visitor numbers, combined with the impact of climate change, prompted the need for a clear, practical plan to reduce energy use and carbon emissions across the estate’s facilities including the visitor centre, café and restaurant and offices. Following a competitive tender, Mesh was appointed to develop an evidence-based strategy to guide building upgrades, balancing sustainability ambitions and the transition away from fossil fuels in this sensitive rural and heritage setting. Mesh took a whole-building approach, assessing how the buildings on the estate currently perform, how they are used at different times of the year in line with fluctuating seasonal visitor patterns, and how future changes to climatic conditions could affect running costs and user comfort. This has enabled Forestry England to make informed decisions on heating solutions, energy supply and building fabric improvements, and to plan upgrades in a phased approach. It provides a clear framework for improving energy efficiency, and importantly, for moving away from fossil fuels. Several of the strategies have already been implemented, delivering immediate energy efficiency improvements whilst informing longer-term refurbishment and upgrading plans. Sophie Nash, Programme Manager at Forestry England: “Our aim with this project was to use detailed analysis to steer our specifications for remediation and upgrading works to improve the energy efficiency and sustainability of our most heavily-used buildings at Westonbirt and the resilience of our electricity infrastructure to support future growth. The assessments carried out which were very thorough and detailed, provide us with valuable insight to inform the design and specification of refurbishment and remediation works in a phased approach.” Doug Johnson, Founder and Director of Mesh: “For rural estates, landowners, parks and visitor attractions across the UK, this project for Forestry England clearly demonstrates how a data-led, whole-building approach can accelerate decarbonisation and create a clear route towards net zero – even in the most sensitive heritage environments and landscapes.” The Westonbirt project reflects growing demand from rural estates, landowners and visitor attractions for clear sustainability strategies that reduce risk, improve performance and support long-term resilience. Image credit - Forestry England / Brian Martin
by Doug Johnson 25 February 2026
The direction of travel for affordable housing is clear. Legislation and policy, including Awaab’s Law and the recently announced Warm Homes Plan, are rightly focused on improving the quality, safety and energy efficiency of affordable homes, whilst tackling fuel poverty and the cost-of-living crisis. Warmer homes should reduce energy bills, improve occupier comfort, support better health outcomes and contribute significantly towards the drive to net zero. However, whilst this ambition is welcome and needed, there is an emerging contradiction – the very measures designed to make homes warmer, more airtight and cheaper to run can also significantly increase the risk of overheating. As climate change brings more frequent and intense heatwaves, overheating is no longer a marginal issue. It is becoming a clear housing risk and even more so for the more vulnerable members of our society. The Warm Homes Plan is fundamentally about enabling people to live affordably in their homes, using modern and renewable technologies to reduce energy consumption and carbon emissions at a time when fuel poverty is rising. That principle is sound. Equally, well-ventilated homes are directly linked to good health and wellbeing. Overheating has a measurable impact on physical and mental health, including sleep quality, metabolic health and productivity. An occupant-centred approach therefore has to underpin the Warm Homes Plan, balancing affordability with health outcomes. The policy’s recognition that passive or active cooling may be required to mitigate overheating is an important acknowledgement that energy efficiency alone is not enough – but it is a complex challenge to address. Why overheating matters – and why it is complex The risk of overheating is surprisingly acute in well-performing homes. Highly insulated, airtight homes – including those built to high specifications and Passivhaus principles – can be vulnerable to excessive internal temperatures if ventilation and heat removal are not carefully designed in at the outset. For residents in affordable housing – including older people and those requiring specialist care – getting this balance wrong has serious consequences. The response to the Warm Homes Plan therefore needs to be right first time, with health and wellbeing underpinned by the appropriate level of technical expertise and correct and ideally regulated execution. The Cooling Hierarchy Well-insulated buildings make absolute sense, but insulation, airtightness and ventilation must be addressed as part of a cohesive energy strategy. Comfort cooling is a more practical solution for reducing temperature. Air conditioning also manages humidity but is energy intensive, maintenance-heavy and costly to run, even when paired with solar. However, there is significant untapped potential in passive measures such as external shading, blinds and shutters – commonplace in warmer climates but still under-utilised in the UK. This is the cooling ‘hierarchy’: 1. Minimise internal heat generation through energy efficient design 2. Reduce the amount of heat entering the home in summer through orientation, shading, fenestration, insulation and green roofs and walls 3. Manage heat within a building through thermal zoning, buffer spaces, exposed internal thermal mass and higher ceilings 4. Passive ventilation 5. Mechanical ventilation 6. Active cooling systems such as air conditioning. The Need for a More Holistic Approach Overheating cannot be considered in isolation. Whole-life carbon, operational emissions from heating systems, materials selection, and long-term maintenance and repair all need to be addressed as part of the transition away from fossil fuels and towards more energy-efficient homes. Ventilation may be key to passive cooling, but real-world constraints quickly emerge. The external acoustic environment matters – homes adjacent to busy roads or railway lines may not be able to rely on opening windows for ventilation without compromising wellbeing. In dense urban areas, background noise can itself become a health issue. Regulatory requirements will also shape the solution. The Building Safety Act requires consideration around fall protection, which may limit window openings through restrictors. Air pollution is another constraint, particularly in city centres. The layout of multi-occupancy housing can severely limit natural cooling strategies. Traditional apartment layouts – with homes on either side of a corridor – make cross-ventilation for cooling extremely difficult, regardless of insulation levels. These inter-relating factors vary widely depending on location, building age and housing typology. Improving thermal performance through additional insulation also introduces the risk of interstitial condensation if ventilation levels are not properly understood. There is no silver bullet or single solution. Designing Building Performance Strategies that Work in Practice The starting point is to treat each building as a whole, rather than a suite of measures to be installed. No single element should be changed without first clarity on how it affects the whole property and its occupants. This requires time, analysis and robust thermal modelling, enabling housing providers to understand, at a systems level, what interventions will deliver the greatest benefit without creating new risks and health hazards such as condensation or overheating. Technology is rapidly advancing. The first ventilation systems with integrated cooling are now available and can be combined with building fabric upgrades and low-energy renewable heating. Where roof orientation allows, solar energy can help offset the additional electrical demand of these cooling systems. But technology alone is not the answer. Occupant profiling is critical. Homes occupied by older or more vulnerable residents, who are likely to remain in the property during the day, need to perform very differently from those properties occupied mainly in the evenings. Overheating in daytime is harder to mitigate than night overheating, and these factors need to inform the performance strategies from the outset. There are significant risks to undertaking blanket upgrades to heating, glazing and insulation without detailed analysis. Homes can take many hours to cool once overheated, and what appears to be a sensible energy upgrade in theory may be hugely detrimental to resident health and wellbeing, increasing risk of non-compliance under Awaab’s Law. There is a delicate balance between resident comfort, health, running costs and carbon emissions, and it cannot be achieved without detailed analysis, modelling and complex calculations. New build affordable homes have more flexibility – window orientation, shading and layout can all be optimised. Retrofit is more challenging. Orientation of roofs or windows cannot be changed; internal insulation reduces room sizes, and the existing interior is someone’s home. The solution will differ from building to building, even across similar typologies. The key is to design for residents – present and future – rather than relying on standardised assumptions. The new legislation rightly raises expectations around building safety, health and affordability, but overheating must be treated as a core risk, not an afterthought. Without a holistic, evidence-led approach, these well-intentioned policies risk poor outcomes for the very people they are designed to help. However, this is also a huge opportunity to increase the affordability, health and resilience of social housing in a changing climate.
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by Doug Johnson 3 February 2026
Mesh has launched a new version of our Embodied Carbon Calculator (V9) to help architects and building designers working at concept stage to generate accurate embodied carbon assessments in minutes. This cost-effective tool has a host of features for automated, super-fast report generation: Architects can now input simple area and materials data and see how their designs perform against RIBA 2030 and LETI targets Different design options can be compared and assessed More than 95% accuracy, even at concept stage Calculate relative embodied carbon values for a wide range of materials and building typologies - input up to 10 different construction types for walls, floors, roofs and other building elements Create 'favourite' custom element build-ups to save time across multiple projects Accurate results to inform planning applications, client reporting and RIBA Award submissions. Watch the demo video here and download the latest version for a one-off fee from our Meshwork platform here .
The Planning consultant's perspective on Mesh and Planning 84
by Doug Johnson 24 January 2026
Rob Hughes, a specialist Paragraph 84 planning consultant shares his thoughts on Mesh and the drivers for success for complex planning projects
Modern, circular building with wooden slats, glass windows, and a grassy field in front.
by Doug Johnson 15 January 2026
Designing a new home in open countryside has always required compelling justification. Under the National Planning Policy Framework (NPPF), Paragraph 84 is one of the few legitimate planning pathways for the creation of new homes on rural or Green Belt land. It is a stringent route – intentionally so – that demands both exceptional design quality and demonstrable sustainability and environmental considerations. The term ‘Paragraph 84′, is the latest iteration of the policy, which was first established in 1997 to set out how new homes can be built in open countryside. Setting a High Bar for Design Quality and Sustainability For architects and planning consultants, Paragraph 84 is an opportunity to create inspirational, landmark architecture. The requirements of the policy set a high bar for architects to achieve with their approach to design. But it is also a policy area where planning authorities demand robust technical evidence from the earliest design stages. These projects have to be designed sensitively to their location and are subject to rigorous review at each stage – from concept, technical design, planning and construction. Without addressing this, proposals will fail to pass the design review panels and achieve planning, leading to costly redesigns and delays. What is Paragraph 84 Designed to Achieve? Paragraph 84 exists to protect and enhance our most sensitive landscapes. It is a national policy pathway that allows new dwellings to be approved for development in open countryside or on Green Belt land when: • The design quality is exceptional • The architecture reflects and enhances the location • The new home would achieve exemplary environmental performance • The proposal results in a dwelling that could not have been delivered using conventional development criteria. Paragraph 84 homes must blend into the landscape and deliver outstanding environmental performance. Projects are typically large, bespoke private homes, where form and materiality relate directly to the context of the site. Schemes draw inspiration from local heritage or the landscape. For example, one of our Paragraph 84 projects sited close to a river was interpreted as two interlocking river boats, or another design near an ancient burial mound was built into a hillside. Paragraph 84 is, at its core, a policy about contextual, site-specific, sustainable landmark design. Why the Number of Paragraph 84 Projects is Increasing At Mesh, we have seen a sharp rise in Paragraph 84 projects in the past year and that trend is continuing. Several converging social, environmental and planning policy trends are driving this: People are moving out of cities – High net worth individuals are increasingly buying rural land to build homes that deliver space, security, privacy and connection to nature. Remote working and advances in technology have accelerated this shift, as has a growing desire to move away from highly urbanised environments. A cultural appetite for exceptional homes – The ‘Grand Designs effect’ and social channels such as Instagram have fuelled the ambition for highly individual, statement homes in rural environments. Planning policy is becoming more rigorous – Local authorities are enforcing sustainability and environmental design requirements far more strictly. Paragraph 84 schemes must now present high-level, evidence-based technical data earlier in the design process and with far greater precision. National planning policy is reinforcing sustainability – Paragraph 84 favours homes that embody sustainable construction, low-carbon energy strategies and responsible material use. As national guidance tightens, planning authorities expect quantifiable evidence rather than simply narrative intent. Demand amplified by Paragraph 84e – Even stricter criteria apply to proposals within National Parks and Areas of Outstanding Natural Beauty, where the architectural and technical design must reach an even more exceptional threshold. This further increases reliance on specialist input for both planning and building engineering. The Role of Building Performance Engineering in Paragraph 84 and Why Early Involvement Matters Paragraph 84 homes do not secure planning consent without high-quality technical input and evidence-based data. Architectural excellence must be matched with detailed environmental studies and data and that requires specialist expertise in renewable technology, performance engineering and building physics. Mesh is one of the UK’s most experienced building-performance specialists in this area and has supported many Paragraph 84 projects since the inception of the policy. Its engineers work with architects and planning consultants typically from RIBA Stage 2, ensuring proposals are grounded in robust, defensible technical data long before design freeze. The key areas of building performance engineering to consider are summarised below. 1. Design Review Panel Preparation Successful Paragraph 84 applications depend heavily on the quality of evidence presented to Design Review Panels (DRPs). These panels expect a clear, data-backed narrative that explains: • The sustainable design strategy • The performance metrics and modelling that underpin design decisions • The rationale for innovation and how that responds to site context • How the scheme meets the ‘truly outstanding’ and ‘exceptionally designed’ criteria of the planning policy. This preparation must be done collaboratively across the design team, with architects, planning consultants and building engineers all aligned. The strength of this early narrative often determines whether a scheme progresses or stalls at the first review. 2. Sustainability and Building Physics Analysis Because Paragraph 84 homes are held to the highest standards of environmental performance, applicants must provide robust technical analysis early in the design process. This typically includes: • Part L thermal efficiency and heat-loss calculations • Part O overheating analysis – often requiring full TM59 dynamic thermal modelling, particularly for large homes with a high level of glazing • Part G water-efficiency calculations • Energy performance modelling. The technical evidence must demonstrate that the building can achieve year-round comfort, comply with overheating regulations, and meet or exceed building-performance requirements. Applying passive measures, such as ventilation strategy and thermal efficiency, play a critical role in compliance with the latest regulations. 3. Energy Strategy and Low Carbon Technology Feasibility Studies A comprehensive energy strategy is a core expectation under Paragraph 84. Design teams must explore low carbon or renewable energy technologies such as: • Air and ground source heat pumps • MVHR and passive ventilation strategy • Underfloor heating • Solar PV and battery storage. The objective is not simply to specify ‘green’ technologies, but to demonstrate – through accurate, interpretable data – that the proposed home will operate efficiently, integrate well with the landscape, and deliver reasonable long-term running and maintenance costs. The Design Review Panels increasingly expect a credible, quantifiable whole-site strategy, not simply a list of technologies. 4. Whole Life Carbon and Material Assessments Given the size and bespoke nature of many Paragraph 84 projects, design teams must account for the impact of both operational and embodied carbon. Data typically required includes: • Embodied-carbon calculations • Material sourcing such as the volume of reclaimed stone or building material versus materials transported to site and from where • Circularity and waste-minimisation principles • Justification for material choices in relation to the local area and the project’s sustainability objectives. DRPs will look for a clear link between the architectural concept, the landscape context, and the environmental logic behind building material decisions and product specifications. 5. Building Services Strategy A common pitfall in Paragraph 84 proposals is not addressing the building services design at an early stage. For these often-large homes, the services strategy has implications for form, structure and landscape integration. Early-stage clarity is therefore required on: • Sizing of plant and equipment • Ventilation strategy and riser requirements • Space planning for plant rooms and roof-mounted equipment • Any constraints that may affect massing or design freeze. Without this early work, design and planning teams risk significant redesign at a late stage – which can seriously delay planning or even undermine the planning case. 6. Ongoing Workshops and Team Co-ordination Paragraph 84 planning approval depends on a cohesive, aligned design team. Workshops throughout RIBA Stages 2 and 3 ensure that: • The environmental strategy and building efficiency match the architectural intent • Technical modelling supports the design narrative being presented to DRPs • The whole team can confidently articulate the detailed evidence behind the proposal • Potential risks of non-compliance are identified well before design freeze. Planning authorities expect clearly reasoned, data-supported submissions – and this level of co-ordination is essential to delivering that. What are the Common Pitfalls to Avoid in Paragraph 84 Projects? Despite the growing demand, design and planning teams can fall into predictable traps. The consequences can be severe – lost design time, repeated panel cycles, unnecessary cost, or complete refusal. 1. Involving building-performance consultants too late Design teams should avoid completing early concept designs without taking account of the implications of thermal performance, overheating risk or services integration. Unless engaged early, by the time the building engineers are brought in, it can be impossible to accommodate regulations or planning requirements into the design – incurring additional work, time and cost. 2. Attending DRP meetings without sufficient technical evidence or data Design Review Panels expect detailed data, not aspirations. Without robust modelling, sustainability metrics or strategy justification, the proposal is unlikely to be endorsed. 3. Overlooking overheating in highly glazed designs Large Paragraph 84 homes frequently feature a high level of glazing to allow panoramic views over the countryside. This increases the risk of overheating. Compliance requires either the simplified Part O route or TM59 dynamic modelling – and most high-specification designs require the latter. Failing to allow for this will result in design amendments that can significantly delay the planning process. 4. Freezing the architectural design before the services strategy is confirmed If plant rooms are undersized, or if roof-mounted equipment cannot be accommodated, the entire form or massing of the building may need to change. This is especially problematic in landscape-led designs or partially sub-terranean structures. 5. Underestimating the impact of whole life carbon and building material specifications Many panels now expect quantified embodied carbon assessments, along with clear justification for material choices and sourcing. Without early data, design freeze cannot be achieved. 6. Assuming compliance can be ‘dealt with later’ For Paragraph 84 homes, sustainability and building performance are integral to the planning case, not a post-design add-on. A non-compliant design will not pass planning, regardless of how well it is presented. 7. Ignoring running costs and operational energy High-end homes can be extremely costly to operate if the energy strategy is not well thought through. DRPs are increasingly asking about longevity, efficiency, maintenance and whole-site energy planning. Why Preparedness is Essential Paragraph 84 opportunities are expanding – but so are expectations. The most successful proposals are those where architects, planning consultants and building performance engineers collaborate from the earliest stages, ensuring design intent, narrative, sustainability and technical evidence evolve together and are fully aligned. This strategy enables design and planning teams to approach DRPs with confidence, clarity and fully defensible data. For architects and planning consultants, engaging the right technical partner early is now not simply beneficial but absolutely critical to the project’s success. Images: Green Fox Farm designed by Hawkes Architecture
Family walks under trees with red and yellow autumn leaves.
by Doug Johnson 9 January 2026
Westonbirt, The National Arboretum near Tetbury in Gloucestershire, has one of the world’s most celebrated botanical collections. It is home to over 2,500 different species of trees and shrubs gathered from across the globe, as well as five national tree collections. Created in the 1800s by Victorian landowner Robert Holford and his family, the 600-acre estate has been managed by Forestry England since 1956. The arboretum welcomes hundreds of thousands of visitors every year and is supported by over 300 volunteers. It also conducts important scientific research and plays a significant role in education and international tree conservation of some of the world’s rarest trees. The arboretum is now one of the most visited pay-to-enter attractions in the Southwest. Visitor numbers have doubled in the last 10 years, putting greater pressure on the park’s infrastructure, along with balancing the additional challenge of climate change. This has created the need for a long-term, sustainable plan to improve the energy efficiency and decarbonisation of the buildings on the estate – from the visitor’s centre, café and restaurant to the Great Oak Hall, offices and other amenities. A Strategic Approach to Decarbonisation in a Sensitive Rural Setting Following a tender process, Mesh was appointed to develop a clear and practical pathway towards reducing operational carbon emissions across the Westonbirt estate. The brief extended beyond simply replacing technologies. It required a holistic understanding of how its buildings perform – from the café and restaurant to the offices, how they will be used in the future, and how climate change will affect user comfort and long-term resilience. For rural estates, parks and visitor attractions, these challenges are increasingly common – constrained infrastructure, seasonal and variable occupancy or visitor numbers, heritage considerations, and the need to balance capital investment with long-term operational savings. Integrated Analysis to Inform Decision-making Mesh carried out a series of integrated building performance and services engineering assessments to help Forestry England understand the feasibility, economic implications and long-term benefits of different strategies. The analysis included: Renewable energy feasibility studies – evaluating air and ground source heat pumps, solar photovoltaics, EV charging, comfort cooling, and low-carbon hot-water solutions for buildings with fluctuating visitor numbers. Fabric optimisation – Assessing walls, insulation, roofs, floors and glazing to identify cost-effective improvements with realistic payback periods and lower embodied-carbon impacts, supporting a refurbishment-first approach. Overheating and ventilation modelling – Dynamic thermal modelling (TM52) to mitigate the risk of overheating in the peak summer months and the impact of climate change on occupier comfort. The study investigated cooling using heat pumps, the viability of mechanical ventilation and heat recovery (MVHR) and solutions to increase natural ventilation as alternatives to carbon and energy-intensive air conditioning. Electrical infrastructure and capacity review – Assessing the existing site electrical supply and predicting energy supply and demand to accommodate future electrification, EV charging and additional loads from Westonbirt’s summer event programme. These analyses used dynamic simulation models for each building to create an integrated energy strategy that simplified decision-making and cost planning for the client. Addressing Rural and Heritage Challenges Each building at Westonbirt presented different challenges, with variations in age, construction type and patterns of use. The Grade I landscape status required careful consideration of installations and changes to heritage buildings. The rural electrical supply was originally designed for smaller-scale loads and required detailed investigation to ensure future compatibility with all-electric systems, such as instant hot water and EV charging stations, and to transition away from fossil fuels. These are issues shared by many rural estates and visitor attractions, where infrastructure constraints and heritage considerations can make decarbonisation a huge challenge without robust technical evidence to inform decision making. Practical Recommendations Mesh’s recommendations focused on realistic, deliverable measures that could be implemented in phases to reduce carbon emissions and energy costs – and using a refurbishment-first approach. Transitioning from the existing gas space heating systems to air-source heat pumps. Using on-demand electric hot-water systems to address significant variations in visitor footfall through the year. Improving user comfort during the peak summer months through natural ventilation strategies, such as automatic opening rooflights, supported by cooling using heat pumps to support the move away from air conditioning. Fabric improvements, such as increasing insulation to roofs and external walls Phased upgrading of the electrical supply to future-proof the estate for expansion and accommodate EV charging and cooling loads, and to create a more resilient estate. Several recommendations have already been implemented, providing immediate benefits whilst informing longer-term refurbishment plans   Supporting the Journey Towards Net Zero for Estates and Attractions Reflecting on the project, Forestry England highlighted the value of detailed analysis to shape decisions and specifications that balance sustainability, user comfort and operational resilience. According to Sophie Nash, Programme Manager at Forestry England: “Our aim with this project was to use detailed analysis to steer our specifications for remediation and upgrading works to improve the energy efficiency and sustainability of our most heavily-used buildings at Westonbirt. We needed to examine the options for upgrading our electricity capacity which is currently constrained with this being a rural site and yet demand continues to increase. The third element was to undertake a detailed study for overheating and how the predicted rise in temperatures would affect some of our buildings and users in the summer months. We are happy with the assessments carried out which were very thorough and detailed. Our intention is to move forward with Mesh’s recommendations and to feed this insight into the design and specification of refurbishment and remediation works in a phased approach. The first of these recommendations have now been actioned.” For rural estates, landowners, parks and visitor attractions across the UK, this project for Forestry England demonstrates how a data-led, whole-building approach can accelerate decarbonisation and create a clear route towards net zero – even in the most sensitive heritage environments. How Mesh Supported Forestry England • Renewable energy feasibility studies • Initial fabric optimisation • Dynamic overheating and ventilation modelling • Building energy and electrical capacity analysis • Low-carbon heating and hot-water strategy If you manage or advise a rural estate, heritage site or visitor attraction and are exploring how to improve the energy efficiency of buildings and reduce carbon emissions, Mesh can provide independent analysis to guide strategic direction for futureproof decision making and long-term resilience in the face of climate change. Images: Forestry England / Johnny Hathaway / Brian Martin / Rob Cousins
Group of people posing by a Christmas tree, some wearing festive sweaters, in a room with a decorated ceiling.
by Doug Johnson 9 December 2025
Doug Johnson, Director and Founder of Mesh: "I would like to wish all the clients, architects, planning consultants and partners we work with a very Merry Christmas from the whole Mesh team. As 2025 draws to a close, I personally wanted to express my sincere thanks for your valued business, collaborations, recommendations and referrals. This year our building engineers have contributed to an extraordinary breadth of work - from projects that enhance the energy performance of existing buildings to award-winning architecture, social housing schemes, rural estates, and public and community buildings. Your sustainability aspirations and trust enable us to do what we love -delivering intelligent, data-driven building engineering that raises the standard of sustainable design to protect and enhance the environment. A special thank you to our brilliant teams across the business, whose commitment, insight and good humour make every project a pleasure and every challenge solvable. Wishing you all a restful festive break, and we look forward to working with you in 2026. "
Group of people in festive outfits, with piggyback, collecting coats and food for charity in a park.
by Doug Johnson 9 December 2025
As the year draws to a close, the Mesh team has been out in the community helping to spread some much-needed festive cheer. From fundraising in Santa suits, food donations for local families and donating warm clothing for those who need it most, the team has embraced the spirit of giving in the run-up to Christmas. Running for a Cause: The Guildford Santa Fun Run Despite the wet weather, members of the Mesh team braved the elements for the Guildford Santa Fun Run, raising money for the children’s charity, Challengers. Joined by Jacqueline Smith from our client TALO, Mesh’s Founder and Director Doug Johnson, along with Maria Fiore and Ilianna Filippopoulou, completed the festive run in full Santa attire. The team also reached their fundraising target, helping Challengers continue its exceptional work in supporting disabled children and young people in the community. Supporting Local Families in Need through the Lions Christmas Food Parcel Appeal For another year, Mesh proudly supported the Lions’ Christmas Food Parcel Appeal, helping to provide food parcels to individuals and families in need over the festive period. Thanks to the generosity of the Mesh team and many local businesses and residents, a huge selection of donated goods is now being sorted and delivered by the incredible volunteers at Lions Farnham. This annual initiative continues to be a meaningful way for us to support vulnerable members of our local community during what can be a really challenging time of year. The Coats for All Initiative Mesh has also taken part in the Coats for All initiative, a brilliant scheme that distributes warm, good-quality coats to anyone who needs one. Through the generosity of colleagues, friends, and partners who donated pre-loved coats in excellent condition, we are helping to ensure that more people can stay warm this winter. Many local libraries are acting as collection points, making this a simple but impactful way for people to support others in the colder months — and we are proud to play our part. According to Mesh Founder and Director, Doug Johnson: “Community sits at the heart of Mesh, and it’s been inspiring to see our team give their time, energy and generosity to support such worthwhile causes - not just this Christmas but throughout the year. Whether running through the rain, collecting food, or fundraising for local charities, everyone has contributed to making a real difference — and I couldn’t be prouder.” At Mesh, we believe that small acts of kindness create meaningful impact. A heartfelt thank you to everyone who donated, participated, or volunteered this year. We look forward to continuing our community support into 2026 and beyond."
Building performance specialist Mesh looks at the Future Homes Standard
by Doug Johnson 6 November 2025
Building performance specialist Mesh looks at the Future Homes Standard - the issues and implications on housing design
Five people with shovels and tools in a field under a blue sky, with other views of the land.
by Doug Johnson 5 November 2025
Members of the Mesh team joined a local charity to help with a tree planting project on the Hampton Estate. This was organised by the Surrey Hills Society, an independent charity who do some great work to encourage people to spend time in the beautiful Surrey landscape. According to Mesh Director Doug Johnson: "We are always looking for volunteering ideas and this charity's work fits so well with our sustainability values. This was our second volunteering day this year. It is very much part of our ethos and culture to make a difference to our environment. These events are also a fantastic opportunity to bring our team together. Thank you to the Surrey Hills Society for a really good day in the autumn sunshine. It’s just so good for the soul!" Five members of the Mesh team joined the day – travelling from Worthing, Bristol and as far as Exeter to help out.

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