Eliminating seasonal energy storage needs through envelope design: real-world cost analysis of quadruple glazing in office buildings

Space-heating peaks and associated seasonal storage needs remain the bottleneck for zero-emission buildings; windows are pivotal because their thermal losses set winter demand. This study’s objective is to quantify the energy, peak-load, and life-cycle-cost (LCC) impacts of argon-filled quadruple glazing (QGU) relative to triple (TGU) and quintuple (5GU) units, and to derive a climate-robust and energy price level criterion for adoption. We coupled multilayer window models to a dynamic simulation (IDA ICE) of an office floor in two climates (Ljubljana, Oslo) across four native SHGC levels, then performed a 30-year LCC analysis using observed manufacturing prices, gross-margin assumptions, and electricity-price scenarios; we mapped cost-parity as a function of heating-degree-days (HDD). QGU systematically reduced delivered heating energy and peak heating power versus TGU, with a small cooling increase, yielding LCC parity in colder conditions at observed prices and margins; in milder climates, parity depended on higher electricity prices or lower margins. The research contributes (i) the first LCC assessment of commercially manufactured argon-filled QGU grounded in measured pricing and dynamic simulation, and (ii) an HDD-based adoption criterion that links envelope choice to lower winter peaks and reduced seasonal storage requirements without added life-cycle cost, offering guidance for high-WWR design and envelope policy.