Do east and west facing solar panels work? Yes. At a typical Central Wisconsin roof pitch, an east or west facing array generally produces somewhere around 80 to 90 percent of what the same array would produce facing due south. That is a real difference, but it is a much smaller one than most homeowners expect, and it is often outweighed by the things that actually decide whether solar makes sense on your property.
South is still the best single direction for annual energy production in Wisconsin. We are at roughly 44 to 45 degrees north latitude, and a south-facing array tilted somewhere in the mid-to-upper 30s will capture the most energy over a full year.
But "best" is not the same as "only." Modeling from the PVWatts calculator and marketplace data both land in the same neighborhood: an east or west facing array typically gives up roughly 10 to 20 percent of annual production compared with south.
Two things move that number:
That is why we do not quote a number off a chart. We model your specific roof planes, pitch, and shade before anyone talks about production.
Roof space is the constraint most homeowners actually run into. A house with two large east and west planes may have far more usable area than the one small south-facing section, and more panels at 85 percent output can beat fewer panels at 100 percent.
Panel efficiency has improved substantially and module costs have come down since the early days of Wisconsin solar. That combination is exactly what makes east and west planes practical today when they would not have penciled out fifteen years ago.
A south-facing array peaks hard at midday. An east/west split flattens that curve: the east side carries the morning, the west side carries the late afternoon and early evening.
That shape matters more than it used to, because of how Wisconsin utilities credit solar. Electricity you use on site offsets your full retail rate. Electricity you export to the grid is typically credited at a much lower buyback rate, often only a quarter to a third of retail, depending on your utility.
So a west-facing array producing at 5 p.m., when the oven is on and the family is home, can be worth more per kilowatt-hour than a south-facing array dumping surplus onto the grid at noon. If you are considering a heat pump, an EV, or battery storage, that afternoon and evening production becomes even more valuable.
This one is not close. Shade is the single biggest production killer we see, and it does not care about your compass. A south plane under a mature oak will lose more energy than an east plane in full sun. We assess shade from trees, chimneys, dormers, and neighboring structures across the whole year, not just the day we visit.
Several Wisconsin utilities already offer time-of-use rates, and rate design comes up in every Public Service Commission rate case. If your utility prices late-afternoon electricity higher, west-facing production gains value. We do not design systems around rules that do not exist yet, but it is one more reason not to write off a west roof.
When we evaluate a site, orientation is one input among several. In practice, these usually matter more:
Direction is on that list. It is rarely the item that decides the outcome.
Then we look at the ground. A ground-mounted array lets us choose orientation and tilt outright, and it can be adjusted seasonally. It costs more per watt and needs open space, but for a shaded or aging roof it is frequently the better long-term answer. We compare both options in the proposal rather than assuming one.
They produce a similar annual total. The difference is timing, west produces more in the afternoon and evening, east more in the morning. West often has a slight edge in value because afternoon production tends to overlap more with household electricity use.
Generally not well enough to recommend. A north-facing array at a typical roof pitch loses a large share of its annual production at our latitude. We would look at another roof plane, a different structure on the property, or a ground mount first.
It depends on the roof and your usage. A split design spreads production across more hours of the day; a single plane concentrates it. We model both and show you the annual totals and the daily shape.
That comes out of the site assessment. We measure your usable planes, account for setbacks and obstructions, and lay out the array before producing a production estimate.
If your roof is within about five years of needing replacement, yes, removing and reinstalling an array later is a real expense. We will tell you honestly if that is the situation.
Do not rule out solar because your roof does not face south. In Central Wisconsin, east- and west-facing arrays are routinely a good investment, sometimes the better investment, once shade, roof area, and how you actually use power are factored in.
The only way to know is to model the roof you have. If you would like to see what your property would actually produce, our team will walk your site, run the numbers, and show you the assumptions behind them.
Northwind Solar has been designing, installing, and servicing solar in Central Wisconsin since 2007. We are a worker-owned cooperative, our designers and installers are NABCEP-credentialed, and we back our work with a 10-year workmanship warranty.
Tell us about your site and we will model your actual production, show you the assumptions behind the numbers, and answer your questions with no obligation.
Request a free estimate | Call us at 715-630-6451