Optimizing a Deep Energy Retrofit Across 864 Design Combinations
ECO Matrix Optimization
Energy model geometry of the existing building and its new addition, viewed from the front (left) and the rear (right). Representative model shown; project details have been changed to protect client confidentiality.
- Educational Facility
- Manitoba, Canada
- Deep Energy Retrofit + New Addition
Case Study Summary
Service | Ecomatrix Optimization Platform (parametric energy & cost optimization) |
Building Type | Educational (deep retrofit of an existing building + new addition) |
Location | Canada (cold climate) |
Floor Area | ≈20,000 m² (≈15,000 m² existing + ≈5,300 m² addition) |
Software | IES-VE (2023 release) |
Standards Compared | NECB 2020, LEED (Canadian ACPs), and an internal Design Intent baseline |
Design Combinations Evaluated | 864 |
The Challenge
The existing building had sat unoccupied for several years and was slated for a deep energy retrofit alongside a new addition, effectively a complete redesign of the architectural, electrical, and mechanical systems. The design team needed to choose the right combination of envelope and HVAC upgrades to maximize energy performance without overspending, but the building’s age and condition meant that choice wasn’t simple: walls, roofs, and infiltration levels varied meaningfully from one part of the building to another, so no single upgrade spec applied uniformly across the whole structure. Comparing options by hand, one combination at a time, wasn’t going to surface the genuinely optimal answer.
Our Approach
We used the Ecomatrix Optimization Platform to run a full parametric sweep across every practical combination of envelope and HVAC variables: 4 wall options × 3 roof options × 2 curtain wall options × 6 window options × 3 infiltration levels × 2 HVAC systems, totaling 864 unique design combinations, each simulated in IES-VE against three baselines.
A key technical complexity: this wasn’t a single-variable sweep. Because the existing building’s construction varied by floor, a ‘wall upgrade’ meant a different assembly on Level 1 than on Levels 2–4 — so each parametric variable was mapped to its real, zone-specific starting condition rather than treated as one uniform envelope. The model reflected the building as it actually was, not a simplified average of it.
Every one of the 864 combinations was scored on:
- Energy Use Intensity (EUI) and % energy savings
- Capital cost premium over the baseline
- Operating cost savings
- GHG emissions reduction
- Simple payback period
That let the design team weigh cost and performance together, rather than optimizing for energy savings alone and discovering the cost implications later.
Results
60.4%
Max. energy savings achievable (best option in every category)
23.2%
Energy savings · 48% GHG reduction — the recommended non-geothermal package (11.9-yr payback)
99.4%
GHG reduction possible with the geothermal package (57.1% energy savings)
The analysis produced two clear, deliverable packages rather than one blanket recommendation: a lower-capital option using a conventional boiler/fluid-cooler HVAC system with a cost-optimized envelope, and a higher-performance option pairing an optimized envelope with a geothermal heat pump system. Within the geothermal path, the sweep showed two different answers. The best-performing combination out of all 864 reached 57.1% energy savings and a 99.4% GHG reduction, at a $2.7M capital premium. The design team then selected a cost-optimized version of that package, balancing energy savings against capital cost: 39.4% energy savings and a 98.9% GHG reduction for a $2.29M premium, with a simple payback of 32.6 years. That gave the owner a genuine choice grounded in numbers, and showed exactly how much performance each extra dollar bought, rather than a single prescribed answer.
Live output from the Ecomatrix Optimization Platform: the option selected by the design team, a cost-optimized envelope paired with a closed-loop geothermal heat pump system, with the full wall, roof, curtain wall, infiltration, and HVAC specification behind it.
Why It Mattered
Rather than the design team guessing at 2–3 ‘reasonable’ options, this optimization surfaced the actual cost-performance frontier across nearly 900 combinations, including where a cheaper envelope upgrade could offset part of the cost of a higher-performance HVAC system, and where diminishing returns made further envelope investment not worth it once a given HVAC system was chosen. That’s the kind of trade-off that’s very difficult to see without running the full parametric set.