Part O Overheating Calculations - Building Energy Experts

Part O Overheating Calculations aim to mitigate the growing threat of overheating faced by dwellings in the United Kingdom, a growing concern due to climate change, increased glazing, and improved airtightness. This can seriously impact the health, comfort, and wellbeing of occupants, especially during warmer months.

To address this, Part O of the Building Regulations took effect in June 2022. Approved document O 2021 mandates assessments for new residential dwellings to limit solar gain and ensure efficient heat removal from indoor environments. This approach evaluates rooms in isolation, improving occupant protection and reducing energy demand.

While Part O primarily applies to new builds, assessing and managing overheating risk is equally crucial for existing properties, particularly during renovations, retrofits, or upgrades involving glazing, insulation, or ventilation.

We provide overheating calculations to support both Part O compliance and to help identify and manage overheating risk in existing buildings. Our services include both the simplified method and dynamic thermal modelling assessments. Learn more about both assessment types and find answers to common questions in our FAQ section below.

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Our expert sustainability consultants are a team of experienced, friendly, and knowledgeable professionals well-versed in building compliance. Get in touch today for a free consultation or competitive quote.

Why work with us?

Experience

Our sustainability consultants have extensive experience in meeting regulatory requirements, yet work hard to go beyond mere compliance with the building regulations.

We pride ourselves on delivering decarbonisation advice to help our clients build lower carbon, energy-efficient properties.

Quality

We reduce the amount of assumed data in each calculation to the bare minimum, meaning that our overglazing calculations are as accurate as possible.

Conversations with clients are key to this process and our work improves each time we work on a new project, thanks to the collaborative approach we adopt with our clients.

Speed

Our office-based staff work hard to book all appointments as quickly as the delivery schedule allows.

We work on a two-week schedule, with the vast majority of overheating calculations being delivered well within that window.

Pricing

Our rate card prices for all services are reviewed regularly, so we’re confident that you won’t find a better service for a better price anywhere else. If you think you’ve found one, we’ll either beat or match it.

Support

Navigating the complexity of energy efficiency, decarbonisation, and building regulation updates isn’t easy.

We’ve worked hard to explain a range of topics related to Part O overheating in plain English to help non-experts get the information they need.

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Looking for fast and reliable Part O overheating calculations in Bristol or nationwide?

Contact us today for a free quote or to discuss your specific project requirements. We offer competitive rates and prioritise fast turnaround times for all our clients.

We’ve worked with Building Energy Experts to support Part O compliance across our developments and have been consistently impressed with their service. Their team is proactive, knowledgeable, and always on hand to provide clear guidance throughout the design and compliance process. Their reports are thorough yet easy to digest, and their input has been instrumental in helping us meet regulatory requirements without compromising on design. The quality of their reporting and technical advice has made them a valuable partner to our team.
Sean Haplin, Technical Coordinator at Redrow Homes – Part O Dynamic Thermal Modelling

We’ve been very impressed with Building Energy Experts on all of our developments. We have found them to be very responsive to our queries and always happy to accommodate any further requests. We recently had an instance of an Energy Consultant going AWOL and urgently required a replacement Energy Consultant. BEE were able to quickly provide a quotation and were appointed within the same day of our initial enquiry.

Their information is always clearly represented, whether that’s in their Sustainability & Energy Statements submitted for Planning or SAP Input Summaries supporting their Design SAPs. I would without doubt, consider BEE, to be one of our preferred Energy Consultants.
Ryan Walker, Technical Manager at Woodstock Homes – Part L, F & O compliance services

Understanding Overheating Calculations: Your Questions Answered

We’ve compiled answers to the most common questions about overheating assessments and Part O compliance to help you navigate this crucial aspect of modern building design.

What is Part O of the Building Regulations?

Part O of the Building Regulations (Overheating) came into effect in June 2022. Its purpose is to mitigate the increasing risk of overheating in new residential dwellings and certain other building types in the UK. This addresses concerns stemming from climate change, increased glazing, and improved airtightness in modern construction, all of which can contribute to internal heat build-up.

What does Part O require?

Part O requires a design assessment to ensure that new residential buildings (and some other specified buildings) are designed to limit unwanted solar gain and provide adequate means for the safe removal of excess heat. This typically involves evaluating individual rooms to ensure they meet the criteria, preventing uncomfortable and potentially dangerous internal temperatures.

When are Part O Overheating Calculations required?

Overheating assessments under Part O are primarily a mandatory requirement for all new residential dwellings, including houses, flats, and student accommodation. They are also crucial for demonstrating compliance during significant renovations or changes of use in existing properties where alterations might impact overheating risk. These calculations are essential at the design stage to ensure compliance before construction begins.

What are the different assessment methods for Part O?

Part O offers two primary assessment methods to demonstrate compliance: the Simplified Method (or “Route A”) and Dynamic Thermal Modelling (or “Route B” / TM59).

What is the simplified method?

This overheating calculation method provides an initial, straightforward assessment of overheating risk based on prescriptive rules and tables. It’s often suitable for simpler, less complex projects and helps identify potential Part O compliance issues early in the design process.

What is dynamic thermal modelling?

For more complex projects, those requiring an in-depth analysis, or projects that have failed the simplified method, TM59 assessments are recommended. This advanced method uses sophisticated software simulations to create a detailed thermal model of the building, providing a comprehensive evaluation of overheating risk under various conditions.

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