Solar panels are installed for efficient utilization of our natural resources and reduce the conventional form of electricity, and they would be at their best if installed on the rooftop. Apart from giving the natural energy source, do you know what other benefits you could reap?
Do Solar Panels Cool the Roof? Well, yes. By giving adequate shade to your roof, solar panels help in considerably reducing the room temperature. Especially when it is the hottest climate of the year, solar panels help generate optimum energy and reduce room temperature.
It is essential to keep in mind that the roof cooling properties of the solar panels depend upon various factors. The installation does not mean your temperature will be taken care of, and this article discusses how solar panels shed heat and help keep your building temperature down.
Let us get started.
Do Solar panels Generate heat?
There is a general misconception that solar panels generate heat while converting solar energy into electricity. The reality is that the solar panels absorb the heat that might have otherwise passed on to the roof.
Solar panels block heat from being absorbed by the roof and keep your building cool. The researchers have also discovered that solar panels also lock the heat at night from escaping in the night, which reduces the heating costs in winter.
How Does the Roof Shed Heat?
Have you ever noticed that dark surfaces absorb more sunlight? Have you tried walking barefoot on a sunny day on the asphalt sidewalks? You could quickly burn your feet. There is a reason why we consider asphalt as an example.
In the United States, the most popular roofing material is asphalt, and the roof is structured with a base material covered with asphalt and filled with granule stones. Asphalt shingles are much cheaper, durable, and work great in absorbing solar energy.
Other roofing materials, including metal and clay, also work great in absorbing the sun’s energy. The maximum sunlight they absorb depends upon how they shed the heat.
There are two ways a roof can shed the heat – either by reflecting the solar energy or emitting the absorbed heat. Let us look at each of them in detail.
Reflecting the Solar Energy
Reflectance refers to the surface reflecting and bouncing back the energy absorbed. Good reflectors cannot absorb the heat very soon. For example – Mirror is a good reflector. If you place the mirror on your roof, it will not become boiling, and this is because they reflect the heat falling on the mirror’s surface.
Similarly, the roof’s reflectance depends upon the color and type of material used to construct them. For instance, the black color is not a good reflector and can easily absorb heat.
Asphalt can reflect 5% to 15% of the sun’s energy, and a cooler material can reflect as much as 65% of the sun’s energy.
Emittance
Emittance is the process where the roof radiates heat. We can explain this process by a simple example. Place a pan in the hot stove and leave it for a few minutes. Once the pan gets heated up, it starts radiating the heat around the surface. If you place your hands a few meters above the pan, you can feel the heat through your hands. The roof also works on the same principle. Emittance is one of the ways the roof can shed the heat absorbed.
How Solar Panels Help In Keeping The Building Cool?
The Solar panels use four mechanisms to keep the building cool.
- Energy Conversion
- Reflectance
- Emittance
- Convection through the air gap
Energy Conversion
The primary purpose of Solar panels is to convert solar energy into electricity. But how much of the absorbed energy is converted?
If you use the solar panels installed for residential use, the panels’ efficiency will range between 16% to 20%. This means that, of the total energy absorbed, the PV panels convert 20% into electricity and aids in the operation of household appliances. Only the remaining sunlight could heat your roof.
Reflectance
Solar panels are good reflectors of energy. Irrespective of the color of the solar panels being either black or dark blue, they can bounce back some of the power falling onto their surface. Solar panels are covered with glass and aluminum frames, which are good reflectors of energy.
Emittance
We all know that asphalt roofs can quickly heat up in the sun. Similarly, solar panels also absorb the solar energy and get heated up.
Solar panels are primarily black or dark-colored for various reasons, and this can make them get heated up quickly, and they, in turn, emit back some of the energy back into the surface.
Sometimes, the heat can get emitted downwards towards the roof and might also heat the roof.
Convection through the air gap
The residential solar panels are generally mounted on a racking system connected to the roof. The racking system is placed several inches away from the roof, giving enough space for the air to flow.
This space can take away the heat from the back of the panels and the roof. The heat absorbed by the panels is also considerably reduced.
How Do Solar Panels Help Insulate Your Roof in the Winter?
Can you believe that solar panels not only can keep your roof cool in the summer but also keep them warmer during the winter? Yes. The solar panels retain some heat in the surface during winter and reduce the room temperature rate.
Other advantages of Installing Solar panels
Your solar panels can not just keep your roof cool but can do much more.
Increase the reflection of solar energy
Solar panels reduce the room temperature in the summer. They don’t insulate your roof from heat. But, you will have the same insulation effect. Do you know how do they do that?
Though solar panels absorb a lot of heat, they reflect some of the absorbed energy. As more and more energy is reflected off the roof, they absorb only a tiny portion and help cool down the roof.
Reduced Thermal Shock
The rooftop gets easily heated during the day and cools down once the sunsets. This drastic change in the climate might cause the roof material to expand and contract. Over a long time, this may create gaps between the roofing material and create a thermal shock.
The solar panels make sure that the roof is not heated up much during the summer, and Similarly, it also keeps the top warmer during the winter. So, the change in climatic conditions does not affect the roofing material, and hence there is no thermal shock.
Reduced UV Radiation
The UV rays of the atmosphere can easily damage your roof by drying out the oils on the roof. Especially if you have set up your roof in timber, the UV rays could create cracks and bleach, and you cannot notice them because it happens over a period of time.
Having the solar panels installed in your roof protects the roofing material under the solar panels from the ill effects of the UV rays. They increase the thermal efficiency and improve the utility and lifespan of the roofing material.
Will My House Become Cooler If I Add a Solar Panel?
It depends. While it is proven that the solar panels could keep your roof cool, the level at which it could maintain the coldness depends upon various factors including,
- Type of roofing material
- Whether there are any external insulation
- Attic ventilation
- Which area is occupied directly underneath the roof
- The level of insulation in your attic and so on.
While so many factors determine the level of heat transmitted into your building. It is always important to keep in mind that the solar panels’ cooling effect comes as an added and a free advantage of using them.
While it is free, you also need to remember that this effect is possible only if you choose conventional solar panels over the shingles. The shingles sit directly on the roof without leaving any air gap, which aids the cooling process.
The same reason will hold good for not installing an aesthetic frame around the perimeter of the array.
Take Away
So, now let us ask the same question. Do Solar Panels Cool the Roof? Yes! They reflect and emit the heat hitting your roof and help generate an environmentally friendly energy source.
Solar panels save our penny not just from generating natural electricity but also increase the overall thermal efficiency of the building. This serves as a better reason to justify the decision to go solar.
We have discussed the various reasons you should go solar in detail. We can hear your pockets filled with those extra pennies after you install the solar panels. Well, if not, what are you waiting for? Your decision has been well justified, and go for it. Go Solar and use the natural resources.
Also, please read our other sections about solar panels to acquaint yourself with the complete details before purchasing a suitable solar power system.