January 16th 2025

How are Architects Leveraging Building Performance Modelling with IESVE?

How are Architects Leveraging Building Performance Modelling with IESVE?

Q&A with Kevin Truss, Senior Architectural Technologist at Coombes Everitt Architects

We recently caught up with Kevin Truss, Senior Architectural Technologist at Coombes Everitt Architects to find out more about how they are embedding dynamic simulation modelling as a crucial part of their design workflow. Read more in this Q&A to discover how architects like Kevin are leveraging building performance modelling to ensure their designs meet client expectations and regulatory requirements, without compromising on aesthetic or environmental performance.

What motivated your practice to integrate building performance modelling software, and IESVE specifically, into your workflow?

The introduction of the Part O overheating regulations in 2022 was a significant catalyst for us. After wrestling with spreadsheets and finding it difficult to achieve compliance through the simplified method, we very quickly realised that we needed to go down the dynamic simulation route.

As a firm specialising in high-end residential dwellings, many of which have large glazed areas, we were already conscious of managing overheating before this point. However, once Part O came into play, we saw the need to formally integrate these considerations into our design process to better understand how our design decisions impact the performance of a building, particularly in terms of heat loss and heat gain.

How has the software impacted your design process?

For our high-end residential projects, maximising natural light and views is a priority. However, if you want to build a house in a lovely prominent position with a fabulous view, it's equally important to understand how that affects the performance of the building. We often see the same situation with non-domestic projects where a mechanical & electrical (M&E) engineer will be appointed to carry out the dynamic thermal modelling later in the process, after many key design decisions have already been made, and the M&E systems are then designed around that. However, we felt there needed to be a step slightly before that in terms of making sure that the design works as passively as possible, before reaching this stage.

Instead of leaving the thermal analysis to the M&E engineers, we try to ensure that we are encompassing passive elements in our building designs from the start. Using IESVE, we are able to understand the performance impact of passive features such as overhangs, shading, orientation, and overshadowing, right from the early design stages. This helps to avoid "fixing" issues with potentially unnecessary or oversized M&E systems further down the line.

This approach is now embedded in how we design all new dwellings, forming part of our pre-planning checks to ensure everything works as efficiently as possible. Depending on the property type, we’ll sometimes also do a pre-planning SAP assessment, just to ensure we've got confidence that the design not only works for the client, but also from a compliance and a performance point of view, before it goes to planning.


What other tools do you use and how do you integrate IESVE with your existing design software?

We use Revit and ArchiCAD, so we typically bring our models into IESVE using an open file format like IFC or via a plugin. While that’s how we typically work at an early stage, we do sometimes also use SketchUp, which due to its plugin functionality, allows us to export our models directly into IESVE and the software will recognise the rooms and spaces that we've already set up. Sometimes depending on the complexity of the building, we may just model directly within IESVE. However, the key we find is to bring the models into IESVE early in the process and you can tweak and adjust as needed. For our BIM projects, we have now integrated IESVE into our BIM workflow as well.

For us, it’s all about being able to bring the models in and being able to check how they perform, which can be achieved in a more simplistic way than you might think. For example, if we are planning to introduce some roof overhangs, or flank shading walls, or some other features, for example external louvres, we can model these very simply in IESVE as 2D shapes and rerun the simulation to see what the effect of that will be. This gives us the principles of what we need from the design and we can then work out how to incorporate the right features into the design model in ArchiCAD. For example, if IESVE tells us we need X metres squared of shading, we can then consider how best we achieve that. Would that simply be extending the roof down? Or might it be some kind of canopy or another feature, like a brise soleil? It’s all about keeping things simple and being able to understand performance early on, so we can adjust the design accordingly.

Was learning these new tools a challenge? What was your experience like?

Initially, it was quite daunting, due to the sheer range of things that IESVE can do. The software is traditionally geared toward engineers, so as an architect, you can feel a bit blinded by all the options. However, the built-in navigators, checklists and guides were immensely helpful in keeping me focused on the areas that I needed to understand, for example the daylighting and shading aspects.  As part of the purchase, we got access to IES’ suite of on-demand learning tutorials, so I worked through those, as well as the user guides, YouTube videos and some of IES’ online CPD sessions, to get up to speed.

Can you share an example of a project where performance modelling made a significant impact?

One standout project was a residential dwelling we worked on for a developer client where we initially tried using the simplified method to achieve compliance with Part O, which proved really difficult. However, by running a dynamic simulation on a very similar design we realised we could get it to work quite successfully with only a few tweaks. This gave us confidence, even for the more unique, high-end projects that we design, that we can make these work without having to install lots of air conditioning or making huge compromises to the way the design looks. Using the dynamic simulation approach in IESVE allowed us to simulate the ventilation much more accurately, and enabled us to look in detail at aspects which the simplified method just doesn’t consider.

What are some of the additional benefits of using this software, beyond regulatory compliance?

We're very visual people in architectural practices, so it’s been especially useful for visualising the impact of our design choices, particularly on the daylighting side. For instance, we recently used the software to simulate the shading effects of external louvres on one property throughout the year. The software’s ability to create first-person perspectives and generate animations means we can provide clients with a real "feel" for how daylighting and shading will affect their space. Being able to quickly pull out a video and send it to a client is really useful and helps us communicate the impact of our design choices much more clearly.

Finally, what would be your one piece of advice for an architect thinking about integrating IESVE, and building performance modelling generally, into their workflow?

Don’t be afraid to make the investment and take some time to learn how the tools might work for your practice. There are plenty of resources and support out there to help you get up to speed. Ultimately, understanding how buildings will perform is a fundamental part of the design process and lowers the risk of expensive design changes at the regulatory compliance stage. Using a tool like IESVE means we can continue to design beautiful buildings people can enjoy, while ensuring both occupant comfort and energy efficiency are prioritised.

For more information on how IES can help architects like Kevin embed building performance from the earliest stages of design, visit our IES for Architects page. 

You can also read more about how Coombes Everitt are utilising IESVE within their design workflow on their blog, via the links below: