Solar Panels in Winter

Winter Solar: Better Than You Think

One of the most common concerns about solar in Canada is winter performance. The truth might surprise you: cold weather actually helps solar panels perform better.

Yes, winter days are shorter and production is lower than summer. But solar panels are remarkably effective in cold, snowy climates. Here's what you need to know:

Why Cold Weather Helps Solar Panels

Solar panels are essentially semiconductors, and like all semiconductors, they work more efficiently when cool. Here's the science:

Temperature Coefficient

Every solar panel has a "temperature coefficient" - the rate at which efficiency changes with temperature. Typical values:

• Standard panels: -0.35% to -0.45% per °C above 25°C
• Premium panels: -0.25% to -0.35% per °C above 25°C

What This Means

On a clear -20°C January day, each hour of sunshine produces more electricity than the same hour on a 40°C July day. The challenge in winter isn't the cold - it's the shorter days and lower sun angle.

Dealing with Snow

How Snow Clears Naturally

Several factors help snow clear from solar panels without intervention:

• Dark surface: Black cells absorb light through thin snow, warming the surface
• Smooth glass: Snow slides off more easily than rough shingles
• Angle: Panels tilted 25-40° shed snow faster than flat surfaces
• Warmth: Even covered panels generate slight heat from ambient light

Should You Clear Snow?

Generally, no. Here's why:

• Safety risk: Climbing on snowy/icy roofs is dangerous
• Damage risk: Improper clearing can scratch panels or damage frames
• Minimal gain: Lost production over a few days is small in annual terms
• Natural clearing: Most snow clears within 1-3 days

Snow Guard Considerations

Solar panels create smooth surfaces that can release large snow sheets. Consider snow guards if:

• Panels are above walkways, entries, or decks
• Lower roof sections could be damaged by sliding snow
• Local building codes require them

Monthly Production Expectations

Here's what a typical 10 kW system produces throughout the year in Saskatchewan:

Winter months (Dec-Feb) produce about 13% of annual output. Summer months (Jun-Aug) produce about 35%. Net metering ensures summer surplus covers winter shortfall.

Maximizing Winter Output

System Design Tips

• Steeper angle: Panels at 35-45° shed snow better and catch low winter sun
• Microinverters: Partial shading from snow affects only individual panels
• South orientation: Captures maximum winter sun when the sun is low
• Clear surroundings: Avoid locations where trees shade more in winter (leafless branches still shade)

Ground Mount Advantages

Ground-mounted systems have winter advantages:

• Easier to safely clear snow if desired
• Can be angled more steeply for winter optimization
• Better airflow keeps panels cooler
• No roof snow buildup concerns