In late 2025, the firm updated the virtual environment with new tools for modeling thermal bridging to eliminate often time-consuming manual calculations and tools for modeling hazard analysis and risk control systems, without need for coding. Such modeling is essential in design of volumes in hospitals, labs and other environments that require simultaneous heating and cooling. The IES APACHE engine is known for its ability to actually model energy performance instead of just providing options for use of materials or equipment as some other tools do.

The latest IES updates, released in February, include more support for California’s 2025 Title 24 energy code cycle, which allows engineers to generate compliance documentation directly from the same 3D building model they used for design.

In many current workflows, engineers still extract data from a design model and reenter it into form-based tools to produce a compliance certificate. The updated workflow evaluates Title 24 rules directly within the simulation model, reducing manual re-entry and the risk of discrepancies between design model and compliance documentation.

Without the need for coding, heating and rejection coil systems can be modeled.
Screenshot courtesy IES

The update introduces what is called the Climate Assessment Report designed to help project teams evaluate climate risks early in the conceptual design process and generate a report that analyzes location-based climate data to identify current and projected hazards—such as extreme heat. This produces visualizations and narrative outputs that help architects and engineers consider resilience strategies before detailed 3D modeling begins and aligns with requirements such as the climate resilience assessment prerequisite in LEED v5 from the U.S. Green Building Council.

“APACHE is actually an acronym,” says Liam Buckley, IES senior vice president and product manager, who is a voting member of the ASHRAE technical committee. He says the acronym stands for Application for Air Conditioning and Heating Engineering, “so that engineers can generate a slew of variables.”

The new updates to the IES Virtual Environment take advantage of APACHE to do calculations for full loops of heating and rejection coil systems. Also, IES has added locations for its parametric modeling tool to turn the process of modeling a data center or big box retail building from up to five days in duration to collect accurate location data to about one-half day. One problem engineers still had was heat transferring through materials or insulation into spaces where it was not supposed to go and fouling energy use calculations.

“We’ve tried to address that with a major upgrade to the APACHE engine that accurately captures all the thermal bridges in a building,” Buckley says. A tower with under-window air conditioners is one building type that is full of thermal bridges. The new tool identifies the bridges and calculates mitigation strategies from APACHE rather than requiring manual calculations. Users can still decide which provides the best mitigation strategies.

“The first comment that came to us about thermal bridging from a customer was from an engineer,” Buckley says. “He said to me, ‘the architects are going to love this.’ I think it’s really going to open up a new user base for us within architecture, because it gives them something more to optimize.”