Trial / Demo
This summer, IES ran a series of lecture-style sessions covering key analyses that can be undertaken using IESVE. With over 200 questions submitted across the six sessions, addressing each one wasn't feasible. However, common themes emerged within the questions asked.
Read on for the answers to these questions, where we provide expert insights into using IESVE for a range of key analysis areas.
Yes, IESVE has a wide range of keyboard shortcuts available to help you quickly and easily create your building geometry. Find the full range of shortcuts here.
Yes, the grid settings such as spacing or alignment can be changed. Find out more here.
Yes, .DXF files can be imported or exported into IESVE. A file can be attached through the drop-down menu: ModelIT -> Reference Files -> Attach DXF File.
The Pollination Plug-in can be used to import Revit or Rhino models into IESVE. This allows you to use one IESVE model throughout the whole building lifecycle to inform decisions. The plug-in lets you quickly find and fix any geometry errors, whilst improving workflow productivity and enhancing project collaboration. Find out more about Pollination here.
You can use Open Street Maps to quickly generate site data. OSM import works globally, although in some regions it may be required for you to manually draw neighbours. Watch our Tech Tip on using OSM map data within IESVE here.
Yes, u-values can be adjusted by editing the cavity resistance in a glazing assembly. Find out more about this workflow here. You can also generate a window utilizing a target U-value by right clicking on any construction.
In Radiance within IESVE, you can assess potential glare risk by reviewing Daylight Glare Probability (DGP) or vertical illuminance at occupant eye level. If you specifically want to flag spaces exceeding a particular lux threshold, you can use the illuminance maps or point in time results and apply your chosen limit to identify problematic areas. For formal glare assessment, DGP metrics are recommended. You can find more information on DGP here.
IESVE supports daylight analysis aligned with major certification frameworks.
You will need to compare the generated results against each scheme’s specific thresholds and calculation methodologies.
SunCast performs direct solar radiation analysis and includes shading from surrounding objects and topography. SunCast calculates direct and diffuse solar exposure (if you tick this on in analysis), including the effects of surrounding buildings and the ground, using ray-tracing methods to determine how solar radiation interacts with building surfaces and the surrounding environment.
However, Radiance based daylighting can include reflected light from internal surfaces and ground/environment when defined as a reflectance value in constructions (ApCDM). Radiance is a more robust, ray-tracing application for lighting simulation that can model complex luminous effects, including detailed inter reflections.
Master Templates within IESVE allow users to import and merge IESVE model data from a source master template into an active project. Custom templates can also be created for specific project properties and shared between projects using the Master Templates functionality. Watch our Tech Tip on the Master Templates Wizard here.
ASHRAE Loads calculates heating and cooling loads using the ASHRAE Heat Balance Method. ApacheSim performs a full dynamic simulation, simulating your building as it changes throughout the year. ApacheHVAC is the detailed HVAC system modelling environment in IESVE. It allows users to build, simulate, and optimise HVAC systems with granular control over components, schedules, airflow, plant, and control logic. Results include system level performance, coil loads, ventilation behaviour, equipment sizing, and energy use.
In short:
When SunCast is enabled, Apache uses the detailed, geometry accurate solar gains and tracking generated by SunCast. This incorporates precise shading from adjacent buildings, fins, overhangs and orientation.
When SunCast is not enabled, the model uses a simplified solar gain method with less granular shading assumptions.
As a result, enabling SunCast typically provides more accurate peak loads especially for highly glazed or complex shaded buildings.
Ventilation loads can be forced to meet ASHRAE Standard 62.1: Ventilation for Acceptable Indoor Air Quality and ASHRAE Standard 170: Ventilation Standard For Health Care Facilities, or can be based off design inputs. User-defined ventilation inputs include:
Available in IESVE 2024 and newer, IESVE’s Parametric Simulation tool is best suited for early-stage design, allowing architects and designers to test and optimise various scenarios at the whole building level. Find out more about Parametric Simulation here.
Yes, energy simulation results are highly sensitive to the weather file, local climate, solar exposure, humidity, and local design conditions. Even models only a few kilometres apart may produce different results when using different weather files. Always select the weather file appropriate to your project’s location or regulatory requirements.
Thermal bridging can significantly increase heat loss and heating energy demand, often by 10–30% depending on construction quality, junction design, and climate. Within IESVE, thermal bridges can be included using psi-values and linear heat loss elements, making energy results more realistic. Highly insulated buildings or cold climates tend to be more sensitive to thermal bridge impacts.
Yes. Series simulations allow the model to use the end of the month internal conditions as the starting conditions for the next month. Parallel simulations treat each month as independent, using default initial conditions.
Series runs therefore produce more realistic transitions between months, especially for heavyweight thermal mass buildings. Parallel runs may speed up scenario testing but can diverge slightly from a full continuous simulation.
Including an HVAC system in ApacheHVAC introduces system efficiencies, control strategies, ventilation management, distribution losses, coil performance, and part-load behaviour. Therefore:
The peak loads may differ depending on how ventilation, heat recovery, and control strategies are configured.
In ApacheHVAC, multiplexing allows you to define one HVAC system configuration and then apply variations (e.g., different coils, control settings, or airflows) across multiple spaces or thermal zones. It streamlines model setup by enabling one system template to serve repeated or similar areas.
Partially. ApacheHVAC will autosize system flows, fans and plant equipment (including pumps by using pump curves), and it uses a system pressure drop parameter for fan and pump energy calculations. However, it is not a full hydraulic duct or pipe-sizing tool that outputs detailed pressure loss (Pa/m) and recommends commercial pipe, duct diameters, or off the shelf pump selections. Although that being said, IESVE does allow flowrates and design airflows to be exported and used as inputs for external calculations.
Updates propagate automatically. If model geometry or room attributes change, you simply re-run ASHRAE Loads or ApacheSim, and the HVAC system can be re-sized using the updated loads. Multiplexed systems update quickly, making iterative design changes efficient.
The CO2 levels from the Apache simulation will serve as your background conditions for the MicroFlo. This BCF file you import to MicroFlo contains the specific CO2 levels (and temperature, airflow, etc.) that MicroFlo uses as the starting point for the detailed CFD analysis of that specific moment in time.
Yes - although MicroFlo is primarily designed for indoor CFD, you can also model external outdoor air movement and temperature fields within the tool. We have PPD & PMV metrics included for internal and external analysis within the MicroFlo viewer. You can then export these temperatures and report them against a UTCI range. Find out more on the MicroFlo viewer here.
This setting tells MicroFlo which face of the opening the imported flow should be applied to. Left/Right/Top/Bottom refer to the orientation of the CFD mesh cell faces.
Choosing the wrong face can reverse or misalign the airflow direction, which can change results. The correct selection ensures the mass flow enters/exits through the intended boundary.
Yes – server racks can be imported as components with heat gain assigned to them. Learn more about our data centre solutions here.
You should use the weather file closest to your model’s location, or as per regulation guidance for your specific project. IES has a wide range of weather files available on our portal, providing global coverage, with free and paid for options available. Find out more here.
The weather file formats the VE can read are .fwt (proprietary format) and .epw files.
It is best practice to use the same model for all analysis. Different aspects of performance are interconnected, so you will get an integrated result.
Yes – you can find more on how to get started with IESVE on our On-Demand Learning platform. The On-Demand Learning provides Training videos to work through at your own pace, such as the recordings of this year’s Learning Academy. You can access our On-Demand Training here.
IESVE is available to purchase in packs that include the most popular applications for specific analysis types. You can browse the packs here and select the one that works best for you!
