My Net Zero Home Got Me Through a Wisconsin Winter — Here’s What I Learned

By Amber Westerman

Is it really possible to get through a Wisconsin winter on solar electricity alone? We had a 10-day cold snap last February and it got down to minus 17 degrees F. My air-source heat pump (mini-split) was working hard — and consuming lots of power. 

When I set out to build a net-zero house (and afford it), I knew my design had to be small and smart. My goal was a grid-tied, all-electric, fossil-fuel free, net-zero energy home that was super-insulated and super-airtight. I knew I couldn’t spend freely on uber-expensive windows or cutting-edge high performance materials. I’d have to rely on mostly standard construction methods and off-the-shelf products. I learned from other builders that the cost of extra layers of insulation and the hours spent sealing up every hole and seam could be partially offset by replacing a standard forced air gas or oil-powered furnace and separate air conditioner with a single, centrally located ductless mini-split powered by a solar photovoltaic system.

To further reduce my electricity load, I chose energy-efficient appliances and LED lighting. Even so, was I risking bursting pipes, weekend service calls, or a spartan lifestyle just to prove a point? What was all this going to cost? How many solar panels would I need? What’s a reasonable payback? Would I have to alter my design? Aren’t solar panels ugly? Would my house look like a middle school science project? Here are the steps I took to answer these questions:

Step 1: How much electricity will my home use?

Before I could select a mini-split or decide how many solar panels to install, I had to know how much electricity my home would use. I looked at a number of energy modeling programs before choosing REM/Design. This user-friendly software is recognized by ENERGY STAR and comes with a free 14-day download. I knew my foundation, wall, and ceiling insulation R-values from my plan. To complete the required inputs, I looked up the manufacturer’s specifications for my proposed windows, heating/cooling equipment, appliances, and lighting. The program predicted my electricity loads would be:

Function kWh/year

Heating: 5,246

Cooling:   527

Hot Water: 3,040

Lights & Appliances: 4,601

Total Electrical Demand:           13,414

This article is comes from Zero Energy Project. The Zero Energy Project is a non-profit educational organization whose goal is to help home buyers, builders, designers, and real estate professionals take meaningful steps towards radically reducing carbon emissions and energy bills by building zero net energy homes and near zero energy homes. We envision the day when positive energy homes, which produce more energy than they consume, will power electric vehicles as well as homes, so that everyone can live well with less expense and without fear of energy price spikes, while greatly reducing our carbon emissions. You can learn more about Zero Energy Project’s Mission & Vision HERE