Expanding a building is a positive step for any organisation, but it also means the services that support the space need to work harder.
Heating, ventilation, and air conditioning (HVAC) systems are designed around the original layout of a property, so when new rooms, extended floor areas, or higher occupancy are introduced, the existing system may no longer be suitable.
If the HVAC requirements of the expansion are considered too late, the result can be uncomfortable working conditions, reduced air quality, and higher running costs. Taking a structured approach early in the project helps you avoid these issues and ensures the expanded space performs as intended.
A good starting point is understanding how well your current HVAC system operates. This establishes whether it can be extended or whether an upgrade will be the more reliable choice.
You may already have indicators that the system is under strain. These can include rooms that regularly feel uncomfortable, inconsistent temperatures throughout the building, or a noticeable rise in energy use over time. Repeated faults or an increasing need for maintenance can also suggest the equipment is approaching the limits of its performance.
A brief overview of how the system is currently behaving can highlight potential issues before any design work takes place.
Any extension changes how much heating and cooling a building requires, so a heat load calculation is essential. This calculation looks at several variables that influence demand, such as:
This is the point where assumptions can easily lead to problems. A system that is too small will struggle to maintain comfort, particularly during peak conditions. One that is too large will cycle inefficiently, increasing operational costs unnecessarily.
If future changes are expected - such as planned recruitment or the introduction of new machinery - it’s often cost-effective to factor these into the calculation from the outset.
As buildings expand, different parts of the property often develop different heating and cooling needs. Office areas, meeting rooms, warehousing, production spaces, and specialist rooms rarely require the same conditions.
Introducing independent heating and cooling zones helps maintain appropriate temperatures in each area and prevents energy being used where it is not required. This is particularly valuable in buildings with mixed-use spaces.
Upgrading controls or moving to a building management system (BMS) can also improve oversight, providing clearer visibility of system performance and allowing adjustments to be made more efficiently.
Where a system relies on ductwork, the expanded building layout may require changes to its design. Ducts that were originally sized for a smaller footprint may not be capable of supplying adequate airflow to new areas, even if the main plant has sufficient capacity.
Signs of poorly adapted ductwork include uneven airflow, hot and cold spots, and unnecessary noise. Extending ducts without reviewing the design can compound these issues.
Ventilation also needs attention. A change in occupancy levels, floor use, or building layout may require higher ventilation rates, better filtration, or changes to extract systems to maintain indoor air quality and comply with workplace expectations.
A building expansion is often the point at which organisations revisit whether their existing HVAC system is still appropriate. In many cases, an upgrade offers greater reliability and efficiency than attempting to extend older equipment.
Common upgrade options include:
The right choice depends on how the building will be used and the level of control required. A qualified engineer can outline the practical benefits and long-term costs of each option.
Any new or modified HVAC system must meet current UK regulations. Even if your existing system is compliant, increasing capacity, adding new equipment, or altering the system layout can change your responsibilities as the operator.
Energy performance (Building Regulations Part L):
New HVAC equipment must meet current efficiency requirements. Extending an older plant may not be acceptable unless the combined system achieves the necessary performance levels.
Minimum Energy Efficiency Standards (MEES):
Upgrading or replacing equipment can influence the building’s energy rating. For rented commercial properties, the system must contribute to keeping the building above the minimum MEES threshold.
F-Gas Regulations:
If the upgrade increases the refrigerant charge size, you may move into a higher leak-testing category. Larger systems may also require the installation of a fixed leak detection system to meet regulatory requirements.
Reviewing these obligations early helps avoid delays and ensures the updated system meets the required standards.
HVAC considerations should form part of the early planning for any building expansion. The system needs to integrate with architectural plans, electrical layouts, and ventilation routes, so delaying this input can limit design options later.
A qualified HVAC engineer can:
Early technical support helps ensure the final system is both practical and efficient for the expanded space.
A building expansion places new demands on your heating, cooling, and ventilation systems, and careful planning is essential to ensure the extended space performs as expected.
Reviewing the existing setup, understanding the new requirements, and integrating the right solutions early in the process all help the project run smoothly.
At Loughborough Air Conditioning, we support organisations through this process from start to finish. Our engineers assess existing systems, advise on suitable options for the expanded space, and design solutions that meet both operational needs and regulatory standards.
With over 25 years of experience, and a range of professional accreditations, we ensure your extended building remains efficient, compliant, and comfortable for the long term.
