There Still Seems To Be Some Confusion As To Whether Solar Panels Should Face West or South
The vast majority of the northern hemisphere’s solar panels are oriented to face south.
Solar panels always face true south if you are in the northern hemisphere, or true north if you are in the southern hemisphere.
There is some data to suggest that this is wrong…or at least, this is the information which keeps surfacing.
This data was first published by Pecan Street, and was eventually echoed by Quartz, Gizmodo, and Grist.
According to this recent study, changing the orientation of homes in the Austin, Texas area yielded startling results, and many researchers have since come to believe that west is a more suitable direction for solar panels to face.
The findings concluded that the average house in a sample of 14 houses with west-facing solar arrays produced more electricity than the average of 24 houses with south facing solar panels.
This, unfortunately, wasn’t 100% true, and even Brewster McKracken, CEO of Pecan Street Inc, admitted that he didn’t expect the findings of west-facing array producing more energy during the test period was statistically significant due to the small sample size.
What is interesting to note, however, is that the study did uncover some relevant information.
When solar panels face west, they yield the greatest amount of power during the late afternoon hours. Typically, they will generate around 55% of the maximum energy production between the hours of five and six o’clock.
A south-facing unit, on the other hand, only yields about 15% of its peak capacity during these hours. For example, a large western-oriented panel might produce 4,000 more watts than a south-facing counterpart.
While it’s true that southern-oriented panels generate more electricity around noontime, this energy is less useful to the homeowner…and the electrical grid.
And therein lies the crux of the matter, and the reason why this misconstrued information keeps surfacing.
People generally use more power and pay higher rates in the late afternoon. A west-oriented panel makes a building 11% less reliant on the grid at peak hours.
One reason why south-facing photovoltaic systems remain common is also due to the fact that American utilities generally pay flat rates to homeowners who send excess solar power back into the grid. Although this is more helpful for the utility, panel owners don’t actually benefit from generating more electricity during peak consumption hours.
People with high electric bills are more likely to switch to solar power in the first place, and they usually draw less grid electricity than the average homeowner. Unfortunately, they actually use more in the late afternoon and evening once they start using major appliances, watching television, or even charging their electric cars.
Even though it does make sense for some homeowners to point their solar panels to the west, the benefits of western orientation doesn’t make it worthwhile to reposition existing units just yet, so don’t start to panic.
It does, however, make sense for more solar panels to face west than we find nowadays because the power they produce is, in some cases, more valuable.
Rather than installing west-facing photovoltaics, homeowners should first consider mechanical sun-tracking devices. Trackers automatically reorient panels to collect the most sunlight throughout the day. This increases power generation by nearly 50%! Such devices can, unfortunately, be costly.
On the other hand, if a home’s design permits it, another option is to simply install a combination of south and west-facing panels on the roof.
Tom Miller
