Part O Overheating Calculations

Assessing the risk factors of excessive indoor temperatures in residential properties

Ensuring regulatory compliance for you, and maximum comfort for your occupants

Overheating calculations can be difficult to understand, with complex data and regulatory requirements that often disrupt the design process. They are, however, part of a mandatory trio of services for new residential buildings that also includes SAP calculations and water calculations.

Energy Digest will simplify the process by aligning with the cooling hierarchy, a proven approach to managing thermal discomfort. Our team will provide clear, actionable advice that integrates seamlessly with your design, exploring simplified calculations or Dynamic Simulation Modelling approaches to produce your overheating calculations, depending on your project’s needs.

Why do you need this service?

Ensure the comfort of
your inhabitants

To prevent heat stress, it’s important to ensure your property can maintain safe indoor temperatures, particularly if it has high solar gain or is in a dense urban area.

Support sustainable
design practices

To lower the building’s energy usage, its design needs to minimise reliance on energy-intensive cooling strategies.

Future-proof your
buildings

Prepare your constructions for more intense and prolonged hot weather with the changing climate conditions.

Our Process

Collect your building
information,

gathering architectural plans and system details

Book your initial
consultation,

during which we’ll discuss project-specific goals and challenges.

Conduct a detailed thermal performance analysis 

following the principles of Dynamic Simulation Modelling.

Review your
results and 

implement strategies to address overheating risks.

Issue overheating
analysis reports, 

providing comprehensive, regulation-compliant documentation.

Support throughout
construction 

to help keep your project on track.

Why choose Energy Digest?

All our overheating calculations are developed according to the standards set out in the Part O Building Regulations, which were introduced in 2022, and CIBSE TM59.
Our peer-reviewed assessments ensure complete compliance, for unrivalled peace of mind.

Our overheating calculation service includes multiple revisions as standard, ensuring we can adapt to your designs as they evolve over time. And because our team follows the cooling hierarchy, they can suggest tried-and-tested strategies that will help you prevent overheating efficiently. 

Fast turnaround time

To help you meet your own deadlines, we’ll ensure your overheating calculations are issued within 7 days.

Multi-disciplined team

We cover 20+ services in the built environment, with specialists providing high-value calculations and strong advice.

Practical solutions

Our professionals provide recommendations that are calculated to ensure real world outcomes, resulting in cost-effectiveness and high impact.

Unrivalled support

Our service doesn’t end with the reports. We can provide ongoing support and expertise, from planning to completion.

Speak to our
experts today

FREQUENTLY ASKED QUESTIONS

Overheating Calculations
FAQs

Factors include extensive glazing, insufficient ventilation, high internal heat gains, poor shading, and building orientation.

Simplified calculations use standard assumptions for basic risk estimates, while dynamic simulations provide detailed, hourly analysis tailored to the building’s design and environment. Dynamic simulations are more likely to comply with regulations.

Yes, by incorporating passive cooling strategies such as natural ventilation, shading, thermal mass, and high-performance glazing.

Thermal mass absorbs and stores heat during the day and releases it when temperatures cool to stabilise indoor climates.

External options like overhangs, louvres, or trees are most effective. Internal solutions like blinds offer additional support but are less impactful.

Passive Cooling vs. Mechanical Cooling

With rising temperatures and urban heat, UK buildings face increased overheating risks. However, passive cooling remains the preferred strategy over energy-intensive mechanical systems. Solutions like shading, natural ventilation, and thermal mass enhance comfort while reducing costs and environmental impact.

Mechanical cooling would strain an already stressed electricity grid, exacerbating energy demand. Overheating calculations focus on responsible, energy-efficient measures that align with the UK’s long-term sustainability goals, avoiding a reliance on high-energy cooling systems.

Spoke with Josh who not only reassured me but asked for a fee that I thought was fair. Thank you Josh. Use again? Definitely.

Steve Quirk

The team really know their stuff – super helpful and always had clear answers to any questions or compliance issues we ran into. Definitely our go-to for any future projects!

Nathan Donnelly

Quick and well priced water calculation service and received an appliance specification report alongside the certificate which was really useful for us and the building control officer, highly recommended!

Ilma Akhtar

Very knowledgeable about building regulations, and the industry. Always goes the extra mile to help out! 5*

Karim Meraga

Still unsure?

We offer free phone call and email support until you’re ready to proceed with us.
Access free support for your project now.

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