Whole Building Energy Modeling (WBEM)

At AECO, we recognize that achieving true sustainability requires shifting the focus from prescriptive compliance to holistic, performance-driven design.

Our Whole-Building Energy Modeling (WBEM) services provide architects, developers, and engineers with the analytical power needed to optimize building performance, secure prestigious certifications like LEED, and ensure long-term operational efficiency.

The Core of Analysis: Comprehensive Energy Simulation

Whole-Building Energy Modeling is the definitive tool for quantifying a project’s potential. Unlike simple spreadsheet calculations, WBEM involves a rigorous 8,760-hour analysis. This simulation models the building's performance for every single hour of the operating year using site-specific climate data.

By virtualizing the building before ground is broken, we allow project teams to interpret the complex effects of design decisions—from glazing selection to HVAC zoning—predicting performance throughout the entire life cycle of the facility.

ASHRAE 90.1: Establishing the Performance Baseline

For projects pursuing the LEED EA Prerequisite: Minimum Energy Performance, WBEM is the standard compliance path (Option 1). The goal is to demonstrate that the proposed design achieves a specific percentage improvement (e.g., 5% for new construction) over a standard baseline.

This baseline is calculated strictly according to ANSI/ASHRAE/IESNA Standard 90.1, specifically utilizing Appendix G (Performance Rating Method). In this process, we model two buildings:

The Proposed Design

Your actual building with its specific efficiency measures.

The Baseline Building

A "digital clone" of your project that adheres only to the minimum prescriptive requirements of the standard.

The gap between these two models forms the basis of your LEED score. The wider the gap, the higher the points—and the greater the energy savings.

Passive Design First: Reducing Loads Before Sizing Systems

At AECO, we emphasize integrating energy modeling early in the concept phase, transforming it from a final compliance check into a powerful design tool. The most cost-effective kilowatt is the one you never have to generate.

We utilize preliminary "Simple Box" modeling during pre-design or schematic design to optimize passive strategies:

Massing & Orientation

Assessing how rotation and shape impact solar heat gain and daylighting.

Envelope Optimization

Tuning insulation values (U-values) and Window-to-Wall Ratios (WWR) to minimize thermal transfer.

Internal Loads

Optimizing lighting power densities and equipment loads.

By focusing on load reduction first, we often dramatically reduce the need for large, costly active mechanical systems, saving capital costs while improving efficiency.

Integrating HVAC: The Holistic Approach

Once passive loads are minimized, the detailed simulation phase ensures mechanical systems are right-sized and optimized.

WBEM allows for complex HVAC system interaction modeling. It accounts for intricate trade-offs that simple calculations miss. For example, investing in a high-performance building envelope might seem costly in isolation, but if it allows the engineering team to downsize the central chiller plant, the net economic result is often positive.

Conclusion

Energy modeling is not just about paperwork; it is about precision. By employing this systematic approach, AECO provides a clear, verifiable path to high-performance buildings. We help you navigate the complexities of ASHRAE and LEED, ensuring your project operates in harmony to achieve the optimal balance of energy conservation, thermal comfort, and indoor environmental quality.

Beyond Compliance:
The Power of Whole-Building Energy Modeling (WBEM) in High-Performance Design