Do Solar Panels Work in Winter? What You Need to Know

With winter comes colder temperatures, shorter days, and the belief that both factors negatively impact solar panel efficiency. 

This is a misconception. 

Even in the dreary winter months, photovoltaic (PV) panels still harvest the sun’s light and convert it into electricity. 

Solar panels transform light — not heat — into electrical energy to power your home.

Although short winter days mean a significant decrease in exposure time to sunlight, solar panels efficiently uptake whatever sunlight is available and convert it to usable electricity. 

Read on to learn how winter impacts electricity production from photovoltaic panels — And how to optimize your solar array and balance of system for cold and snow. 

The Link Between Solar Panels and Temperature

If you’re a newcomer to solar technology, you may be surprised to learn that photovoltaic (PV) modules like solar panels perform better in cooler temperatures than in extreme heat.

The ideal temperature for solar panels to function optimally is 25°C (77°F). Manufacturers use that temperature to rate solar panel specifications in a laboratory under Standard Test Conditions.

Standard Test Conditions for Solar Panels

Condition Type	Standard Test Condition	Real-World Conditions
Solar Incident Angle	Always zero, irradiation beam always normal to the PV panel*	Variable and depends on time, date, and site latitude. In the case of rooftop systems, roof orientation and inclination govern system capacity.
Solar Irradiation	Always equal to 1000 Watts/m²*	Variable and depends on the time, date, and site latitude. Limited sunshine hours bound system capacity.
Ambient Temperature	Always 25°C*	Variable and depends on the time, date, weather condition, and site latitude. Higher ambient temperature degrades PV panel efficiency and reduces system output.
Air Mass Coefficient (AM)	Always equal to 1.5*	Variable and depends on the time, date, and site latitude. Higher AM with higher latitudes.
System Losses (e.g., Wiring, Inverter)	Always Zero*	Variable and depends on the design and location of PV panels, inverter, and grid meter.

*Cannot be achieved in real-world applications (Source: ResearchGate) 

When assessing solar panel performance, the laboratory temperature is always 25°C (77°F). The efficiency of photovoltaic modules declines as the temperature of solar cells increases to more than 30°C.

Aside from its everyday meaning, “efficiency” is a specific metric for PV modules. It measures the percentage of direct sunlight a solar panel can capture and convert into DC electricity under the Standard Test Conditions above.

Efficiency is an essential factor to consider when purchasing solar panels because it directly impacts how much surface area you require for installation and how many modules you need to meet your electricity consumption needs.

All things being equal, a solar panel with lower efficiency will require more surface area to produce the same amount of electricity.

For example, the EcoFlow 400W rigid solar panel has a rated power output of 400 watts and dimensions of 67.8×44.6×1.38 inches (172.2×113.4×3.5cm). Its monocrystalline silicon solar cells achieve 23% efficiency under Standard Test Conditions. The two-dimensional surface area of the panel is 22.5 square feet.

A polycrystalline silicon solar panel with 18% efficiency and 400W of rated power would require approximately 5% more surface area to achieve the same level of electricity production. The approximate 2-D surface area will be 29 square feet.

If you’re working with limited space for installation, it’s easy to see how lower solar panel efficiency presents a problem. It impacts how much surface area receiving direct sunlight you require for installation AND how many solar panels you need to achieve your desired electricity output.

Considering efficiency is essential when making a purchase decision. Lower-efficiency polycrystalline and thin-film solar panels may cost less than monocrystalline silicon, but you’ll need more space and potentially more panels.

The most crucial factor for calculating solar panel efficiency is solar irradiation, which is always assumed to equal 1000 Watts per square meter (m²). In the real world, that level of solar irradiation is most frequently achieved in the early afternoon hours of peak sunlight. 

How Does Heat Impact Solar Panel Efficiency

Somewhat counterintuitively, solar panels decrease in efficiency in extreme heat.

(Source: Energy Education)

Solar panels use the photovoltaic effect to generate electricity by capturing photons from sunlight (not heat). As the temperature climbs above 25°C (77°F), the properties of the semiconductors within the panel shift, resulting in a slight increase in current but a much more significant drop in voltage.

In some locations, like deserts, where direct sunlight is plentiful, PV modules require cooling mechanisms to operate at peak efficiency. 

Bear in mind that it’s not the ambient temperature that impacts solar panel efficiency. It’s the increased heat of the solar cells in the panel.

While it’s true that extreme heat does diminish solar panel efficiency, it’s essential to note that the more hours of peak sunlight you receive in your location, the more electricity your residential solar power system will produce. 

One study found that commercial solar panel efficiency didn’t begin to decline until the outdoor temperature reached 43°C (109.4°F). 

Extreme weather events are becoming more commonplace, and temperatures are rising worldwide. 

However, if you live in Canada, it’s unlikely that ambient heat will significantly diminish the performance of your residential solar panel array.    

How Does Cold Impact PV Module Efficiency

Cold temperatures combined with peak sunlight are actually ideal for solar panel efficiency and performance. 

Extreme cold can negatively impact solar panel performance — as can heavy snowfalls. But we mean extreme — as in extended periods of -40°F (-40°C) or below.

However, you will generate less electricity on average during the winter than during summer. 

This decrease in production is not due to a drop in temperature but rather to reduced hours of peak sunlight.

While your solar panels increase in efficiency during the cold months, there is less available sunlight for the modules to capture during the day. 

Let’s look at the impact of winter conditions on electricity production — not solar panel efficiency, where there’s more likely to be a positive effect.

Do Solar Panels Work in Winter?

PV modules work in any conditions where photons from the sun reach the photovoltaic surface.

Electricity production is diminished on highly overcast days, but solar panels can generate electricity even when there’s only ambient — as opposed to direct — sunlight.

As long as the panel remains unobstructed, it will produce electricity even in climate conditions that reduce direct sunlight capture.

Do Solar Panels Produce Less Energy During Winter Months?

Yes. 

Even if you live in a state that stays relatively hot year-round — like Arizona or California — the number of peak sun hours per day will be significantly less in winter.

In the Northern Hemisphere, the days leading up to Winter Solstice — around December 21st — get progressively shorter. After that, the days gradually get longer until Summer Solstice (around June 21st).  Then, the whole cycle begins again.

If you live in a region that gets relatively few hours of peak sun — even in summer — you’ll likely feel the pinch of decreased electricity production during winter even more acutely.

For example, Ithaca, NY, on average, gets some of the fewest peak sunlight hours in the US. 

During the summer, it averages 4.57 hours of peak sun per day, which drops to 2.29 hours in winter — a decrease of 50%. 

That doesn’t necessarily mean a homeowner in Ithaca will generate half as much electricity in winter as in summer. But production from the solar panel array is certain to take a serious hit.

Even in sunny California, winter has an impact. Los Angeles gets an average annual daily high of 14 hours and 15 minutes of daylight light. In winter, the shortest day declines to about 9 hours and a half hours — approximately ⅓ less. LA averages about 5.6 hours of daily peak sunlight. 

If you live in Tucson, AZ, where the longest day is 14 hours and the shortest day is about 10, you should still receive more than enough peak sunlight to power your home. The average peak sun hours are 7.5 hours daily during summer and 6 hours during winter.

However, back in snowy Ithaca, the already short peak sun hours are cut in half. 

No matter what state you live in, your solar power system will produce less electricity per day during the winter months, not because of the cold but because of the lack of light.

Do Solar Panels Work in Cold Weather?

Solar panels perform better in temperatures around freezing or above than in extreme heat. 

Solar panels that use silicon — monocrystalline or polycrystalline — rarely decrease in efficiency due to cold unless temperatures drop below -40°F (-40°C). 

In most parts of Canada, it’s unlikely that temperatures will remain below -40°F — at least not for extended periods. 

In short, it’s a common misconception that solar panels don’t work in cold temperatures. In fact, the opposite is true. Solar panel efficiency is less affected by extreme cold than extreme heat.

However, aside from reduced peak sun hours, there’s something else that can adversely affect electricity production in winter. 

Snow.

Do Solar Panels Work in Snow?

Solar panels produce electricity by harnessing photons from sunlight.

Anything that prevents sunlight from reaching the solar cells beneath the protective surface of the panel (usually tempered glass) will adversely impact electricity generation or even halt it completely.

Allowing snow to collect on the surface of PV panels can have this masking effect. A light snowfall typically won’t affect your solar panels, especially if they’re positioned at an angle where the snow can slide off.

However, after a heavy blizzard, you may need to clear snow from your solar panel array or hire a professional to do it for you. 

If it’s safe for you to clear the panels yourself, do not use a scraper or power washer. Instead, use a specialized tool like a foam-headed snow broom or a simple household broom with soft bristles. Either implement allows you to clean the panel’s surface without causing damage.  

Another thing to keep in mind about snow is that — like rain, hail, or any other natural precipitation — it’s produced by clouds. Solar panels continue to generate electricity on cloudy days, but production is diminished.

What Are the Benefits of Using Solar Panels During Winter?

Even if you live in a cold weather state, there are many benefits to using solar panels during winter.

Once you account for environmental factors like peak sun hours, the benefits of switching to solar power are the same for locations with cold winters as for states that remain hot.

Here’s a quick summary.

Clean, Renewable Energy 

Harnessing solar power for some or all of your residential electricity needs is good for your pocketbook — and the planet.

Transitioning away from fossil fuels is necessary for the survival of life on Earth — at least as we currently know it. 

(Source: Environmental Protection Agency)

In the US, electricity generation is second only to transportation in burning coal and petroleum products that produce greenhouse gas emissions. 

By embracing a virtually limitless source of clean power from the sun, you can do your part by reducing your carbon footprint at home.

Less Reliance on Grid Power 

Not only is climate change threatening the Earth’s future, but it’s also creating unpredictable temperatures and extreme weather events with increasing frequency.

With wildfires, blizzards, heat, and cold waves sweeping Canada at least once a year (or more), aging grid infrastructure is under greater strain than ever.

Events like the months-long Texas 2021 power outage that left millions without power and contributed to 700 deaths or more are becoming more commonplace.

If you invest in an off-grid or hybrid solar power system — or a portable power station for home battery backup — you can protect your home and your family during even extended outages.

Reducing dependence on the grid is one of the best ways to achieve energy independence and security.  

Lower Electricity Bills

One of the primary benefits of switching to solar power is saving on electricity bills — or eliminating them altogether.

Even when subjected to harsh winter weather, solar panels last for decades — often 30 years or more. 

If you’re like most Americans, you’ll achieve solar payback during the first 6-10 years of purchasing a PV panel array and balance of system. 

Over the long term, your return on investment from switching to solar can be substantial. 

Money saved is money earned.

Using renewable energy also frees you from the uncertainty of rising fuel costs and the negative consequences of supply and demand. 

With solar energy, demand never exceeds supply.

Tips for Preparing Your Solar Panels for Winter

High-quality mountable solar panels are incredibly durable and can endure decades of harsh weather conditions.

If you purchase IP-68-rated PV panels from a reputable manufacturer, your array should require little, if any, maintenance — regardless of the season. 

However, there are a few things to keep in mind and simple steps to optimize performance.

Find out more below.

Keep Solar Panels Clear of Snow

Be proactive about clearing any snow from the surface of your solar panels. When snow covers your solar panels, their ability to capture sunlight is diminished. If a snowfall buries your panels, sweep them off to clear them. In the process, you’ll clean the panels and make them even more efficient.

Never use a power washer, antifreeze, scrapers, or industrial cleaners on your solar panels. It’s easy to damage the protective surface with abrasion, reducing lifespan and performance. 

If Not Fixed, Adjust the Angle 

In Canada, your solar panel array should always be installed to face south (if possible) to maximize sunlight capture. 

Many PV panels allow you to quickly change their angle even once mounted on your roof. If your solar panels are adjustable, you should tilt them as winter approaches to capture more light. 

A quick and straightforward method for determining the optimum angle for your solar panels by season is to Google your location’s latitude or zip code. As a general rule, the best angle for your solar panels is equal to or close to your latitude. In winter, the ideal angle is your latitude +15°. In summer, it’s the opposite at -15°.  

Additionally, if you live in an area with heavy snowfall, you should consider altering the angle to help snow slide off the panel more easily without human intervention. 

According to Energy.gov: “Higher tilt angles allow snow to shed from systems more quickly and reduce the risk of damage. The steeper the angle, the better the snow shed (up to 60 degrees). 

Significant gains are seen around 30–35-degree tilt angles, which is significantly steeper than a typical roof. The steeper the module tilt angle, the less snow weight is transferred to the module.”

However, extreme tilt can also make solar panels more susceptible to wind damage. Be sure to strike a balance.  

Maintain and Insulate Solar and Backup Batteries

If your residential solar power system is off-grid or hybrid (on-grid + storage), it must include solar batteries.

Depending on your solar battery chemistry, you may need to maintain it routinely and keep it from getting too cold.

Lead acid batteries require regular maintenance to function and prolong their limited lifespan. 

Additionally, lead acid batteries have a narrow ideal temperature range. To maximize longevity and performance, lead acid batteries should be kept between 68°F (20°C) to 25°C (77°F).

Traditional lead acid and valve-regulated lead acid  (VRLA) batteries like AGM and Gel will charge and discharge outside that range. However, operating a lead acid battery at a temperature even 15°F higher will cut its lifespan in half. 

If you drive a car on the East Coast, you already know how hard colds are on lead-acid batteries. At subzero (celsius) temperatures, they will charge slower and discharge less power. Partially charged batteries can freeze at -16°F (-27°C), and many manufacturers recommend not using them at all when temperatures drop to -32°F (-35°F).

Lithium-ion battery chemistry and newer subsets like lithium iron phosphate (LiFePO4) are better suited to cold weather. 

For example, the EcoFlow DELTA Pro Ultra hybrid solar generator has an optimal operating temperature range of  -4°F to 113°F (-20°C – 45°) and a dust and splash-resistant IP54 rating.

DELTA Pro Ultra is expandable up to 90kWh of LiFePO4 battery storage, 21.6kW of AC output, and 16.8kW of solar charge capacity (42 x 400W EcoFlow Rigid Solar Panels). More than enough to power almost any home — all summer or winter long.         

Frequently Asked Questions

Consider Going Solar This Winter

There’s never been a better time to switch to clean, renewable solar energy for your residential electricity needs.

Thanks to increased demand, competition, and innovation — coupled with generous government incentives —  the upfront investment in solar panels and a balance of systems is more affordable than ever.

Whether you live in a state that gets frosty in winter or basks in the heat year round, the time has come to make the solar switch.

You’ll be doing your savings account — and the planet — a huge favour.

If you’re hunting for solar panels with industry-leading efficiency and durability that will last you decades — and best-in-class balance of system components — the search is over. 

Check out EcoFlow’s mountable and portable solar panels today.