Exterior of Arvig Office building located in Minnesota
•	SageGlass and GEOThermal conducted energy analyses to predict energy savings for an integrated smart window system and ground coupled heat pump system.
The renovation of Arvig office building added 22,000 sq ft of additional interior space.
GEOptimize Inc.
BHH Partners
SageGlass Classic
Project Size
6,200 ft² / 576 m²

The Challenge

Arvig, an internet service provider, planned a large renovation of its Minnesota office building, adding 22,000 square feet. The project team wanted to create a modern workspace with plenty of natural light and outdoor views, and without the overheating and glare that often affect spaces with lots of windows. They also worked with local electrical utility and geothermal companies to improve the building’s energy efficiency and reduce energy costs.


The Solution

Geothermal company GEOptimize, which worked with Arvig on its ground coupled heat pump system (GCHP), suggested pairing the GCHP with smart windows from SageGlass to help manage heating and cooling loads. The system takes advantage of a readily available heat source (sunlight coming through the windows) to lower the building’s demand for heat. When the smart windows are automatically tinted in bright sunlight, they help lower the demand for cooling, too.

How well would this first-of-its-kind dual system—the GCHP plus smart windows—improve energy efficiency for Arvig? The project team developed building-energy models, with different solar heat gain coefficients, to run simulations and analyze 20-year temperature trends and system efficiencies. They accounted for weather patterns, climate-change scenarios, office room usage scenarios, and more. The models showed that the building’s annual cooling demand would decrease by 32% when the SageGlass smart windows were fully tinted.


As the concern of climate change and awareness of greenhouse gas emissions increases, commercial building owners will be forced to design energy-efficient buildings. A building with a high window-to-wall ratio allows for a symbiotic relationship between a geothermal system and dynamic glass.
Connor Dacquay


The Benefits

In addition to the 32% decrease in cooling demand, the project team also predicts that the integrated GCHP/smart windows system will reduce the building’s carbon dioxide emissions by 30% and reduce the 30-year net present value of the system by more than $140,000. The system is also fully automated: Sensors collect data, and Arvig’s building automation system uses that information to set the tint level of the SageGlass smart windows. The employee workspaces offer plenty of light and views of the surrounding natural landscape, and the smart windows keep the air cool and comfortable, without the need for blinds or shades.