As we slide into summer, you may be guessing your solar panels will generate more electricity. And you’re probably right, which is good news for your air conditioner! But why? Hours of sunlight in a day has something to do with it, as do weather patterns. And it all starts with the Earth’s tilt. Here are the factors contributing to how seasons affect your solar panels.
How Seasons Play A Role In Solar Panel Output
A quick refresher (since for just a few of us elementary school was a while ago): the Earth’s 23.5 degree tilt results in seasons. As the Earth orbits the sun, its tilt means one of the hemispheres receives more direct sun than the other at different times throughout the year. Seasons don’t change because of Earth’s distance from the sun, but because of Earth’s tilt.
And Earth’s tilt impacts the ideal angle for solar panels. Think about it this way: if the sun was directly over your solar panels all day, their ideal angle would be zero so they could soak up all that light overhead. But because of the angle of the Earth, the sun won’t be directly overhead at all times of the day. And in the DMV, it will be lower in the sky in the winter and higher in the summer.
Turns out the ideal angle for solar panels for annual production is your location’s latitude. That’s close to 39° in DC. Tilting solar panels at the angle of your location’s latitude allows for more light to hit your panels.
However, most solar panels are mounted at the pitch, or slope, of the roof. And few roofs in DC are 39°! (In roof terms, that’s very steep.) But don’t worry if your roof angle isn’t the ideal — this only results in a production loss of a few percent. Considering the Earth’s tilt simply adds context to thinking about how much power your solar panels produce seasonally.
Other Solar Panel Seasonality Factors
Roof direction also makes a difference for solar panel output — a much bigger difference than roof angle. Generally, solar panels on DMV roofs facing south will generate more power, as they’ll receive more sun thanks to the Earth’s tilt and our position north of the equator, as the sun appears to move in the sky south of us. Roofs facing east or west, and potentially some north-facing roofs with no shade, will work for solar as well.
As you may expect, hours of sunshine each day also impact solar panels during the seasons. You don’t need us to tell you there are more hours of sunlight in a day during the summer than the winter! What you may not know about are peak sun hours. These are hours during the day when, to put it technically, sunshine produces 1,000 watts per square meter. The solar industry considers peak sun hours as a measure of how viable solar is for a geographical location; generally a place should receive four or more peak sun hours. Weather and latitude both impact that number. The DMV gets around 4.0 to 4.9 peak sun hours a day, which is great! And, surprise, surprise, we’ll receive more peak sun hours in the summer.
Solar Panels By The Seasons
Hot And Humid DC Summers
So not only more hours of sun, but more hours of intense sun, during the summer will allow your solar panels to generate more power. But what about other elements dominating our summer days — namely humidity?
You guessed it: solar panels don’t love humidity, which can degrade solar cell insulation. This won’t happen all in one summer, though, but over the lifetime of the panels. And humidity concerns mostly apply in tropical locations with more constant humidity, like Florida.
The other major summer factor is heat. Turns out solar panels actually prefer cooler temperatures! The reason why is that heat means more resistance in electrical wires, so electricity can’t flow as effortlessly. The DMV has its fair share of hot days (again, you don’t need us telling you that!) but on certain cooler summer days, solar in Washington, DC has an edge over solar in hot, desert climates like California or Arizona.
And solar panels will work in far higher temperatures than we receive in the DMV — think 185 degrees Fahrenheit. They won’t overheat. Hotter days simply mean your panels aren’t quite as efficient. But they’re still generating power.
With equipment that sits exposed on your roof — as solar panels do to generate power — you can’t avoid every weather condition. Even with summer’s heat and humidity in DC, your solar panels will likely generate more power in the summer than any other season, thanks to all those wonderful hours of sunlight.
Brisk DC Winters
Winter is something of a balancing act for solar. Solar panels love a good sunny, cool day. Too bad the days are shorter! And the panels do work in rain and light snow, and even on cloudy days, just not as efficiently — but this weather cleans off your panels, which means more sunlight can reach those solar cells.
These trade-offs do mean it’s worth it to go solar even in a DMV winter. We have a whole blog post on how solar panels stand up to winter weather; check it out here.
Get The Most Out Of Your Solar Panels Each Season
Uprise will design your system and position your panels to help you get the most out of your solar array. But you can also analyze your electricity consumption habits to potentially save more. The DMV’s climate means you’ll likely be blasting that air conditioner in the summer and running your heater in the winter, and we’re not suggesting you roast or freeze. Instead, you can reduce your energy consumption in creative ways like, for example, routinely cleaning or replacing your air conditioner filters, which can lower energy consumption by as much as 15 percent.
We’ve got plenty more ideas on how to conserve electricity to maximize your power bill savings by season! Here’s our blog post on 10 DIY energy efficiency projects geared towards the spring and summer months, and our blog post on 9 ways to save power targeted more towards fall and winter.
It’s Always A Good Time Of The Year To Go Solar!
If you’re thinking about getting solar panels for your roof, there isn’t necessarily one season that’s better than another, especially since we do tend to run our ACs and heaters. Plus, the solar process can take a few months while we wait on approvals from your local jurisdiction and utility company, so now is a great time to get started.
Reach out to our team to schedule a conversation about whether solar is right for your roof here. You can also call us at (202) 750-5718. We’d love to partner with you on your solar journey!