coombes:everitt News Dynamic Thermal Modelling

Dynamic Thermal Modelling

May 8, 2024

Sunpath Image

The Part O Building Regulations, introduced in June 2022,  require that a design is checked to ensure that it does not overheat in the summer months.

With the increase in insulation levels and increase in new building air tightness, we have benefitted from much better thermal performance in new buildings, reducing the overall heating load and lowering the amount of carbon that’s used to provide energy to a building. This has however increased the risk of summertime overheating and the new regulation has been drafted to tackle this potential risk.

What is thermal modelling?

The simplest way to assess a building is using what is referred to as the simplified method, which is essentially calculating the percentage of glazing on each elevation against tables published in the regulations to ensure that a building does not have excessive glazing that could result in summer time overheating due to solar gain. This method is incredibly restrictive however in terms of design flexibility and very difficult to pass with more complex building designs.

The alternative method is using what’s called Dynamic Thermal Modelling, which utilises software to simulate the building throughout the year and check the heat loads within the building for each month of the year.

Investing in thermal modelling software

Coombes Everitt have recognised that investing in thermal modelling software and integrating it into the design workflow from concept to completion, provides us with an immense amount of design flexibility to ensure our buildings comply before they are submitted to planning and way before the design develops into a set of Building Regulation drawings.

This lowers the risk of expensive design changes at building regulation stage and having to go back to planning with design changes. This also allows us to design buildings as passively as possible right from the outset and not have to ‘fix’ a bad passive design with expensive additional mechanical ventilation or air conditioning/cooling, which will all add to a building’s energy use.

Sun Path Simulation

The software also allows us to simulate the sun path throughout the year and assess solar shading, which will also consider adjacent buildings that might cast shadows on the building design and external landscaped areas enabling us to hone the design and the building orientation and location to maximise the benefit of sun or design spaces to avoid excessive solar glare or exposure if required. This also allows us to hone the design of shading devices such as eaves overhangs, Briese Soleil’s, Canopies and other features to maximise their effect.


We can also software simulate and calculate the amount of natural daylight that the building designs habitable spaces are exposed to. This allows us to hone the design to maximise the amount of natural light specific rooms can enjoy (such as living spaces, classrooms or office spaces).

BIM – IESVE Workflow

We already design our buildings in 3D using the latest BIM software. We can now seamlessly pass our BIM design models into the thermal modelling environment and assess them at each workstage to hone the design as it develops. Identifying any potential problems early to inform the design as it develops, rather than fix design problems at later stage when they entering into a more technical design phase.

Ultimately the aim is to continue to design beautiful buildings people can enjoy, but also ensure the building design benefits the occupants as passively as possible, to ensure internal spaces are comfortable throughout the year and lower their energy use as part of the design.

For more information on Part O, get in touch. We will ensure that your new home meets the requirements of the regulations and minimise the cost and time impact, whilst enabling design success.