Solar panels are all round good guys.
They’re like that one friend you have that will go out of his or her way to help anyone. Everyone says they’re good people.
Solar panels give you free electricity, help the environment, and don’t cause any intrusions to your life.
But that’s not all, they go the extra mile to help you save on energy bills and live more comfortably by keeping your roof cool.
That’s right, solar panels make a perfect friend to your AC as they reduce your roof temperature during hot summer days.
You might not realize how hot a roof gets when the sun is beating down on it all day.
Have you ever touched a sidewalk during a heatwave? The asphalt gets searingly hot, in fact, it can even start to melt! And the most popular roofing material in America is asphalt shingle.
So if you’ve got or are looking to get solar panels then you’ll be pleased to know they will help to cool down your roof.
Solar Panels Reduce Roof Temperature
Researchers at UC San Diego Jacobs School of Engineering discovered several surprising results when analyzing the effect of solar panels on the heat of a rooftop.
Led by Jan Kleissl thermal imaging showed the temperature of a ceiling was 5℉ cooler when covered with solar panels compared to an exposed area of roof. In this scenario, it meant a 38% reduction in the amount of heat reaching the rooftop.
This is more than just a nice anecdote and actually translates to real world energy savings. The research further identified that this led to a noticeable reduction in energy usage in cooling a building with AC. In fact, it translates to a 5% saving in electricity cost thanks to selling the extra energy back to the main grid.
Reasons Why Solar Panels Cool Your Roof
So why are solar panels so effective at reducing the temperature of a roof? Well there’s a number of reasons from shading to airflow. Let’s take a closer look.
Shading
The most obvious way a solar panel keeps your roof cool is the shading. Instead of the sun beating down on the surface of your roof it is obstructed by the solar panel. As no light is passing through the panel it creates a strong shadow underneath where it is mounted. The solar array is effectively acting like a big sun umbrella across the rooftop. The heat from the sun is not being absorbed by the roof and transferred into the building, stopping it from overheating in the first place.
Airflow
In addition to the shading, solar panels are not mounted flush to the roof. There should be a gap between the base of the panel backsheet and the rooftop. This is for a number of practical reasons including heat dispersion. The gap helps to create a draft as cool air flows between the two surfaces helping to carry away excess heat.
Energy Conversion
We already discussed how the solar panels block the direct sunlight creating a shadow on the roof. But what happens to all this energy and heat that lands on the solar panel?
Well, this is actually what the equipment is designed to deal with as it converts sunlight into electrical energy. Once again this helps to keep your roof cool in a couple of ways. To start with, excess heat isn’t being passed through the panel into the roof and the light energy is being used to create electricity. In addition, this electricity can then be used to run cooling appliances such as air-con and fans to reduce the interior temperature.
Unfortunately, solar panels can still get quite warm on the hottest days and absorb that heat into their materials including the aluminum frame. At some point, this heat must leave the panel via emittance which either goes back into the air or into the roof. Generally, this doesn’t heat up the roof thanks to the convection and airflow mentioned above.
Reflection
Even with their deep black color and efficient energy absorption, solar panels will still reflect light and heat. This is not bad for keeping your roof cool as it reflects the heat back into the atmosphere. Plus the tempered glass and aluminum frame will have a level of reflectiveness to rebuff the heat from your rooftop.
Do Solar Panels Generate Heat?
No solar panels don’t generate a lot of heat. The majority of energy hitting a solar panel is converted into electricity. You will only find solar panels get hot on the warmest days of direct sunlight. This is the sun warming them up rather than heat being generated from their operation and components.
As you can probably understand by now, a hot solar panel is not bad for your roof. In fact, it is a good sign that your solar panels are absorbing heat rather than the roofing material.
6 Tips for a Cool Roof (and the rest of your house)
Got a hot roof? Let’s look at ways you can cool down your roof. Of course, these techniques can be combined with solar panels for the most benefit.
Solar Hot Water System
Installing a rooftop solar water heater is a great way to cool your roof and benefit from the heat at the same time. Instead of the sun’s heat hitting your roofing material and heating up your house, the energy goes into your water heater. This offers efficient benefits including free hot water, reduced energy consumption, and a cooler roof!
Go Green with Plants
If you have a flat or accessible roof you should think about going green. This involves creating a rooftop garden with plants in pots. The plant leaves will add a lot of shade plus soil, pots, and planters will help to absorb extra heat.
Just be sure that you have a flat, strong, and waterproof roof before trying this one.
White Cool Roof
In hot climates such as California, cool roofs have grown in popularity during recent decades. It involves covering or painting the rooftop in a reflective material, the easiest way to do this is specialist white paint.
And the brilliant thing is that cool roofs and solar panels go together like peanut butter and jelly. It will actually improve the efficiency of your solar array as the sun is reflected off the roof into the solar cells.
In fact, it can even increase solar efficiency and reduce cooling energy cost by 20%.
Open Upstairs Windows
The easiest way to keep a house cool including a roof is to open the upstairs window in a house during summer. You should do this early in the morning before the sun takes full effect. This is because heat rises so it will naturally flow to the top of your house. If you don’t let this heat escape it will build upstairs, into the attic, and roof. Creating an airflow will help to keep temperatures cool as warm air dissipates out of the windows.
Attic Insulation
Properly insulating your attic won’t keep your roof cool but it will stop your feeling the effects in the rest of the house. Insulation keeps the heat from passing from your roof into the interior air of your home. Plus, it keeps you warm in the winter.
Install Solar Panels
Yes, that’s right. If you’ve got a hot roof install solar panels. If you’ve got the summer sun beating down on your house then it is the perfect location to mount a solar array. The solar panels will block the heat from your roof and convert light into electricity. You can then use that power to run your AC for free.
Do Solar Panels Insulate Your Roof in Winter?
Yes, solar panels do insulate your roof in cold temperatures but the effect is pretty minor. To be honest, you won’t notice any noticeable difference in winter insulation with solar panels mounted. The airflow and metal frames of the panels aren’t going to help you retain warmth in a building. Although, there is some evidence to suggest that solar panels can help reduce heat escaping at night.
Final Words on Do Solar Panels Cooling Your Roof
So there you have it. A resounding yes, solar panels do reduce roof temperatures.
Both the theory and scientific research backs this up and it’s easy to understand why.
The two biggest factors are shading and energy conversion. Solar panels shade your roof like an umbrella while converting the sun’s energy into electricity.
For a cooler roof, get solar panels.
