Parametric Evaluation of Envelope Strategies for Energy Reduction in Cold-Climate Buildings

Envelope design influences building energy performance by affecting heat transfer, solar gains, daylight availability, and indoor thermal conditions. Glazing systems, façade shading, and thermal mass are frequently evaluated during early design to reduce operational energy demand and improve building efficiency. Understanding their relative influence can support informed decision-making when multiple energy-reduction strategies are considered. This study assesses envelope parameters on annual Energy Use Intensity (EUI) using a parametric simulation workflow in Grasshopper and ClimateStudio. A multizone residential building in Boston, Massachusetts (ASHRAE Climate Zone 5A) was used as the case study. Ten glazing configurations, eight façade shading strategies, and nine thermal mass scenarios were evaluated against a baseline EUI of 48.3 kWh/m²·yr. Simulations varied glazing U-values and Solar Heat Gain Coefficients (SHGC), orientation-responsive shading geometries, and internal slab thicknesses while maintaining consistent geometry, occupancy schedules, and assumptions. Annual site EUI quantified each intervention's effect on operational energy demand. Glazing performance produced the largest reduction in annual energy demand. Triple low-emissivity glazing achieved the lowest EUI, reducing energy consumption from 48.3 to 43.5 kWh/m²·yr, a 9.9% improvement relative to baseline. Double low-emissivity glazing reduced EUI by 7.5%, demonstrating that substantial savings can also be achieved with high-performance double glazing. Shading strategies yielded modest improvements, with west-facing vertical fins achieving the best result at 47.9 kWh/m²·yr. Thermal mass reduced annual EUI incrementally, with maximum reductions of 1.7% at the highest slab thicknesses. The results indicate that glazing selection had greater influence on annual EUI than the shading and thermal mass variations considered. While triple low-emissivity glazing achieved the largest energy reduction, high-performance double glazing provided substantial savings with lower implementation costs. The findings provide a comparative assessment of energy-performance tradeoffs among common envelope strategies and demonstrate how parametric simulation can support cost-informed prioritization of envelope interventions during early-stage design.