Do Solar Panels Cool Your Roof Temperature?

Living in a hot climate can make air conditioning costly. However, solar panels can help reduce your energy bills. They not only generate clean energy but also cool your roof by providing shade. This blog post explores the impact of solar panel shading on your home, considering various factors. Find out how solar panels can benefit you in hot regions.

Roofs get sizzling!

If you’ve ever stepped barefoot onto the pavement on a sunny day, you know how much heat energy a dark surface can collect in only a few hours. So, the question, “Do solar panels reduce heat?” is understandable.

Asphalt also happens to be the most prevalent roofing material in the United States. Asphalt shingles are inexpensive and long-lasting because they are made of a base material that has been coated in asphalt and impregnated with stone grains. Some shady shingles are also very effective at absorbing solar radiation. According to studies, a conventional roof can reach scorching temperatures of between 150 and 185°F during the height of summer.

Roof Reflectance and Emittance

A heated roof will dissipate heat in one of two ways: by reflecting solar energy or by releasing heat that it has previously absorbed.

Reflectance is the term for energy that a surface reflects. A mirror is a great reflector, so it doesn’t become too hot in the sun. But a black car’s hood doesn’t reflect much light and can become extremely hot. The color and type of material have an impact on the reflectance of roofs, which are similar. The coolest roof materials can reflect up to 65% of incoming energy, compared to 5–15% for asphalt roofs.

The heat energy that a hot surface emits is known as emittance. A cast iron pan can retain heat for several minutes after the stove has been turned off if it is heated on the stove for a few minutes. The same is true of a hot roof. One method your roof sheds collected heat energy is through emittance.

Roofs that are designed to keep your home cooler can be between 50 and 60 degrees Fahrenheit cooler than a typical one.

Are there Environmental Benefits?

A dark roof’s ability to absorb heat affects more than simply your own house. Dense cities with plenty of buildings, sidewalks, and roads can absorb so much energy that they can get up to 22° hotter at night and between 1.8 and 5.4° warmer during the day. The heat that is absorbed by roads and rooftops during the day is released at night, keeping cities warm long after the sun has set.

The US Department of Energy launched the cool roof effort to help the federal government reach its greenhouse gas reduction targets because of the heat island effect—also known as the urban heat island effect.

How do solar panels make your roof cooler?

Reflectance

Your solar panels will reflect some sunlight away, just like any other surface. Even if solar cells are dark blue or black, some of the light that strikes them will still bounce off them.

Moreover, the glass covering, and aluminum frame of solar panels will reflect some of the energy away.

Energy Conversion

Solar energy is converted to electricity using solar panels. The efficiency of residential solar panels typically ranges from 16 to 20%. This means that 16 to 20 percent of the energy that strikes your solar panels is transformed into electricity rather than heat or reflection, which is then transmitted through cables as DC current.

To put it another way, solar photovoltaic panels essentially wick away solar energy from your roof and utilize it to power appliances like your TV and dishwasher. This indicates that just 80–84% of the sun’s remaining energy is left to possibly warm your roof.

Emittance

Solar panels also warm up in the sun because they absorb some of the solar energy that strikes them. This is like how an asphalt roof warms up in the sun. Solar panels are often dark, while some are purposefully created to be all-black for aesthetics. They can get rather hot, and a portion of that energy is released back into the atmosphere.

Regrettably, some of that heat is also released downward, toward the surface of the roof, where it may cause the building to get warmer.

Convection Through The Air Gap

The roof is connected to a racking system on which a traditional home solar panel system is placed. The solar panels are held in place by that racking system several inches above the roof surface.

This standoff distance creates a space for air to flow. Your solar panels will collect less heat if that breeze can move heat away from the roof surface and the rear of the panels.

Research

According to French researchers who used modeling to support their findings, rooftops with solar panels experience a cooling effect during the day that continues into the night. This is due to four mechanisms: reflectance, emittance, convection, and energy conversion.

Additionally, having a large number of solar panels installed on rooftops can help reduce the urban heat island effect. This means that both individual households and entire cities can stay cooler.

To demonstrate this, researchers from UC San Diego studied a lab facility on their campus that had solar panels. They found that the ceiling directly beneath the solar panels was approximately 5 degrees cooler than the uncovered part of the ceiling. This data was collected over a three-day period using a thermal imaging camera.

Yes, solar panels can cool your house!

Many people wonder if solar panels can help keep their houses cooler. While the researchers at UC San Diego found that the ceiling temperature in their building decreased by 5 degrees with solar panels, the effect on your home may vary.

Several factors come into play, such as the type of roofing material you have, whether you have external insulation, and if your attic space is occupied or unoccupied. Your attic ventilation and the amount of insulation in your attic also play a role in determining how much heat is transmitted from your roof into your home.

So, while solar panels can contribute to cooling, it’s important to consider these factors to understand the specific impact they may have on your house. One thing is certain…do solar panels make your house hotter? Thankfully, no.

Solar panels have the potential to make your home cooler, but the extent of the cooling effect will vary depending on your specific situation. It’s important to note that the impact is generally minimal. However, this cooling benefit comes as a bonus alongside the main advantage of solar panels, which is to generate clean energy.

One significant advantage of having solar panels is that they can help extend the lifespan of your roof. So, while the cooling effect may be modest, it’s worth considering the added benefit of preserving your roof in the long run.

Conclusion

There is some conflicting information about whether solar panels can actually cool down a roof. Some sources claim that solar panels may increase the temperature of a roof, while others suggest that they can help reduce it.

The truth is, the effect of solar panels on roof temperature can vary depending on factors like the type of roof, materials used, location, and climate. It’s important to consider these individual factors when deciding whether installing solar panels is the best option for cooling your home.

As technology continues to advance, we can expect to see more efficient solar panel systems that will make it even more accessible for people to benefit from solar energy in the future.