Thorstein Chlupp / Riena LLC builds net-zero-energy homes in Fairbanks, AK. He has numerous very long (1-3 hour) videos describing his design methodology and process in detail. The homes are designed, from the sub-grade up, to be as efficient as possibly in a high-heating-need environment. He makes extensive use of thermal mass and insulation, as well as design features minimising heat loss, and maximising gain.

At the core of his homes is a a 5,000 gallon stratified thermal storage tank -- a repurposed fuel tank filled with water, and packed in roughly 1 meter of insulation on all sides. Sourced heat, from solar thermal panels, a wood stove, and other sources, is fed to this. It drives both space and water heat for the structure itself.

Walls have 18"+ insulation, all fittings are thermally isolated, heat exchanges are used on air and water transfers, etc. It's pretty impressive stuff.

For Wisconsin, you might not choose to apply all the concepts, but the idea of banking heat (or chill) in the summer (or winter) through some form of mass storage (ground, tank, other), might apply.

There are community thermal storage systems which have been designed and deployed in both Canada and Germany.

https://en.m.wikipedia.org/wiki/Seasonal_thermal_energy_stor...

http://www.reina-llc.com/