By Laurence Chownsmith, Head of UK Sales, Building Solutions, at REHAU UK

As the UK’s built environment steadily progresses toward net zero, architects are increasingly being relied upon to design buildings that are not only energy-efficient and compliant with sustainability legislation but also ensure high occupant comfort.

Among the technologies gaining momentum in this space is Thermally Activated Building Structures (TABS) technology, a heating and cooling system that uses the thermal mass of concrete to passively regulate indoor temperatures. With regulatory standards tightening in line with climate change, TABS is emerging as a practical and forward-thinking solution for sustainable building design.

The urgency of this shift is underscored by data from the Copernicus Climate Change Service (C3S), which confirmed 2024 as the warmest year on record globally. Similarly, the Met Office has reported that the UK experienced its sunniest spring on record this year, leading into a summer with more forecasted heatwaves. This upward temperature trend is already influencing how buildings are designed, particularly in urban environments where overheating is becoming a year-round concern.

The Science of Staying Cool

TABS addresses this challenge by circulating hot or cold water through pipework embedded in concrete slabs. This allows the structure itself to act as a thermal buffer, absorbing and releasing cool or heat slowly throughout the day depending on changing cooling and heating loads. 

This approach reduces reliance on mechanical systems and helps maintain a stable indoor climate, even as external conditions fluctuate. As such, the cooling provided by TABS offers far more occupant comfort than systems such as air conditioning which are airflow-based and cause cold spots. 

However, the benefits of TABS extend beyond thermal comfort alone. The system’s compatibility with low-temperature heating and high-temperature cooling makes it an ideal partner for renewable energy sources such as heat pumps. It also aligns well with district heating networks, particularly those using fourth-generation technology that operate at lower temperatures. Such features position TABS as a key component in the broader transition to low-carbon infrastructure. By working at energy-saving temperatures, TABS can help facilitate reduced operating costs, compared with more traditional cooling systems. 

Suitability for the Future

TABS projects commonly achieve high BREEAM ratings, with many projects reaching “Excellent” or “Very Good” and some even achieving Passivhaus certification. This shows how well TABS can work in the creation of a highly energy efficient buildings and be suitable for meeting the Green Building Standards. 

Jointing is another key element when looking for futureproof systems and a leak-tight joint is imperative. This is where the renowned EVERLOC compression sleeve technology brings another advantage. Not only is installation straightforward, but the absence of O-rings offers long term reliability combined with the added benefit that the technology requires just a simple visual check to ensure it is leak tight. 

Code Controlling the Climate

Despite its advantages, TABS presents a unique design challenge. The system responds slowly to changes in temperature and should be treated as a holistic approach to cooling and heating, covering 70% and 60% respectively. For building areas requiring faster responses to heat demand – boardrooms, for example – the addition of a fan coil unit FCU is recommended, while perimeter trench cooling can help if the perimeter has a high solar gain.

 Building management systems (BMS) and smart control systems have been developed that are specifically tailored to adjust the needs of high thermal mass systems such as TABS. These systems ensure that TABS operates efficiently and responsively, maintaining comfort while minimising energy use. 

Ensuring Wellbeing Through Detail

The implementation of smart BMS controls also supports broader goals around occupant wellbeing – a key consideration for architects during the specification process. In sectors such as healthcare, education, and commercial office space, thermal stability is closely linked to comfort, productivity, and recovery, and TABS contributes to these outcomes by operating silently and maintaining consistent temperatures without draughts. Consequently, the technology can be instrumental to creating environments that are calm and conducive to their intended use.

This can be particularly important in healthcare settings, where patient recovery can be influenced by environmental factors such as noise and temperature fluctuations. These benefits highlight the importance of embedding systems such as TABS into the design process from the outset, rather than treating them as optional enhancements.

The adaptability of TABS to modern methods of construction further enhances its appeal. As the industry increasingly turns to offsite construction to address skills shortages and accelerate project timelines, TABS can be integrated into prefabricated concrete planks, improving onsite build speed and reducing on-site disruption. The impact of this can be keenly felt in sensitive environments such as hospitals and busy urban streets where minimising noise and dust is essential. Offsite construction can also support more predictable project delivery and meshes well with the growing emphasis on modular, scalable building systems.

Building for the Next Benchmark

In the context of evolving regulations such as the Future Homes Standard and Part L of the Building Regulations, TABS offers a practical route to ensuring structural compliance. Its ability to deliver low-carbon heating and cooling, combined with its compatibility with renewable energy and smart controls, makes the technology a strong choice for buildings aiming to meet or exceed current performance benchmarks.

For architects, this means considering TABS not just as a technical system but as a strategic design choice that supports long-term sustainability goals. Indeed, its success as a building temperature control technology requires coordination across different project stakeholders, including developers, structural engineers, consultants and contractors. 

The structure’s design must also accommodate the embedded TABS pipework, with mechanical systems designed to work harmoniously with the building’s thermal mass. Consequently, any additional temperature control strategies and technologies must similarly be well-planned to ensure responsiveness and efficiency and compatibility.

Dialogue-informed Design

In this context, collaboration with manufacturers and suppliers becomes essential. With working-from-home practices leading to less pooled, in-house knowledge at architectural practices, and those practices moving away from maintaining traditional libraries due to rising floor space costs, the ability to draw on external knowledge and support is increasingly valuable. Indeed, it must be noted that TABS is not a plug-and-play solution – it requires considered design, integration and a commitment to long-term performance.

Ultimately, TABS represents more than a means of heating and cooling. it is part of a design philosophy that prioritises resilience, simplicity, and sustainability in building structures. In a sector where immediate cost pressures often compete with long-term performance goals, architects are uniquely positioned to bridge that gap. By championing systems like TABS and integrating them thoughtfully into the design process, these stakeholders can help shape buildings that are not only efficient and compliant with regulations, but also comfortable, adaptable, and built to last.