Thinking About Going Solar
Residential solar electric systems are known for their unique ability to harness the suns energy and generate free and renewable electricity that your home can use especially during the summer when the days are longer and sunlight is abundant. Youve probably heard that a rooftop solar system can help you lower your utility bills, but did you know it can also keep your home cooler?
Here is a look at how a rooftop system can actually keep your home in Arizona cool, even when temperatures are at their hottest.
Solar Panel Cooling Research From Uc San Diego And France
A couple studies on the effect of solar panels on the temperature of rooftops and the urban environment have been done by researchers in France and UC San Diego.
The French researchers used modelling to demonstrate that the combined effects of the four mechanisms described above not only make rooftops cooler during the day, but the cooling effect continues at night. In addition, the combined effect of many rooftop solar deployments can reduce the urban heat island effect: solar panels can help to keep not just homes but entire cities cooler.
At UC San Diego, researchers examined a laboratory building on campus that has solar panels. Collecting data with a thermal imaging camera over three days, the researchers found that the ceiling underneath the solar panels was about 5 degrees cooler compared to a section of ceiling that wasnât covered with panels.
Their estimate was that the solar panels reduced the amount of energy reaching the roof by 38%. Over the life of the panels, the researchers estimate that this cooling effect adds an additional 5% energy benefit to the system. For a building owner, this is a great âfreeâ bonus of having solar panels.
How Hot Is Too Hot
How much heat can the solar panels on your home really handle? That depends on the solar panel brand you choose and something called its temperature coefficient. When youre shopping for solar panels, youll notice that each different brand has an efficiency rating, with an average efficiency of 15%. A solar panels efficiency rate refers to how much sunlight it can convert into usable energy. Each solar panel brand will also have a temperature coefficient, which explains how well the panels perform in high temperatures.
Generally, solar panels dont begin to lose efficiency until their temperature rises to 77 degrees. At that point, for every degree increase in temperature above 77 degrees, a solar panel loses efficiency by the rate of its temperature coefficient.
You can start to see how hot summer days can diminish the performance of your solar panels. This can be problematic at a time when youll probably want to keep that air conditioning going strong. Fortunately, good solar installers can offer different solutions to help your solar system manage hot days.
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Do Solar Panels Reduce The Heat In A Roof
The use of solar energy to power homes, businesses, and moreover the past few years has grown in popularity.
There are several advantages to using solar power, but one of the unforeseen advantages is that solar panels can reduce the amount of heat that reaches your roof.
Some of the key points I will cover in this article include:
- Heat does enter your home from your roof.
- Solar panels really can reduce the heat that gets to your roof.
- It is important to keep heat away from your roof.
- The average home needs different number of solar panels depending on the size, the scope of what is being run, and the amount of sun that reaches it daily.
- Solar panels on your roof can make your attic cooler.
The sun produces energy that we can invert into usable electricity, now we just have to figure out to efficiently and cost-effectively make that happen.
Can Solar Panels Keep Your Home Cool
While it is well known that switching to solar energy can save you upwards of 90% on your electric bill, did you know that this eco-friendly service can also help to keep your home cool during the blazing Central Florida summer?
Its true! Solar panels provide a cooling service that extend far beyond their ability to provide clean power: because panels on your roof reflect the intense rays of the Florida sun away from your home and create a layer of shade, your home doesnt get as warm, your A/C doesnt have to work as hard AND you get to save on cooling costs. Its like putting a large popup tent over your roof.
A study performed at the UC San Diego Jacobs School of Engineering determined that, during the day, a buildings inside ceiling was five degrees cooler with solar panels compared to those with an exposed roof. The team at UC San Diego determined that the amount saved in cooling costs equated to receiving an extra 5% off the price of solar panels over the equipments lifetime. The study also found that the annual cooling load decreased by 38% for the panel covered roof area.
What Happens Above Your Home?
When direct sunlight strikes a roof:
- Heat is absorbed and pushed into the home.
- An unprotected roof acts like a sponge, pulling in the heat and increasing interior temperature.
- As a result, your air conditioning system is forced to pull even more energy from the power grid in order to fulfill its purpose, adding to what is already a daunting financial burden.
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Choose The Right Solar System Size
When you work with Semper Solaris, well calculate your average monthly energy usage in order to determine the ideal size for your solar system we also know to check average summer temperatures and to keep the temperature coefficient in mind when making our recommendations.
This is just one more reason why you should strongly consider working with a local solar panel installation company. A local company will already be familiar with the weather patterns of your area and will understand how the summer months will affect the efficiency of your solar system.
If you endure long and hot summer months, your installation specialist may recommend a slightly larger solar system to make up for the efficiency loss during days with high temperatures.
Solar Panels Reflect Heat From The Suns Rays
Solar panels are made from materials like glass, silica, metals, and plastics, which are able to reflect heat from the suns powerful rays. These materials are exceptionally more reflective than traditional roofing materials like asphalt shingles. In fact, according to a recent study conducted by the University of California, San Diego, solar panels reflective materials coupled with the fact that panels are typically raised from the roofs surface allow them to reduce heat absorption on a roofs surface by up to 38%.
This means that in the attic and other upper areas of your home, you can expect cooler temperatures. Homes with rooftop solar panels, on average, see a 5-degree drop in the attic and other upper areas. Youll feel more comfortable inside your home and wont need to run your AC system as often.
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Does Heat Enter Your Home Through The Roof
Absolutely. Heat enters your home through your roof, and on a hot day your attic can get up to 150-degrees Fahrenheit or more.
Through a process called conduction, heat from the sun warms your roof which then warms your attic and the rest of your home.
While heat can enter your home in other ways as well, conduction is one of the primary ways that the sun heats your home.
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At my home in Haiti, we do not have an attic and our roof is made of concrete. Throughout the day the sun shines on the roof, and where there are no solar panels, the roof just constantly heats up and transfers that heat down to the rest of the house.
There is a marked difference where our solar panels are and in the amount of heat that they absorb and reflect.
The bottom line is that even in a home with a thick concrete roof, heat is easily conducted from the roof to the rest of the home.
How much more heat could be conducted from a 150-degree attic to the rest of your home even with insulation?
The addition of solar panels to your roof could greatly reduce the amount of heat that gets trapped in your attic and in turn the amount of heat that enters your home.
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The idea is simple: when sunlight hits your house it warms your roof and pushes heat into your home. Installing solar panels will block this sunlight from hitting your roof, thereby preventing heat from entering your house. The researchers found that solar panels can lower a roofs temperature by 5 degrees Fahrenheit, or about 3 degrees Celsius. This can significantly reduce cooling costs over the life of the solar panels. In fact, the researchers determined that the savings from reduced cooling amount to a 5 percent discount on the solar panels price.
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A Few Other Caveats About Solar Battery Systems
If youâre thinking about getting a battery with your photovoltaic system, you should be aware of a few more things before you make your decision:
- You will probably only be able to power critical loads. One of the installation steps with most solar battery system is the addition of a smaller electrical panel next to your main panel. This is called the critical loads panel. During a blackout, your inverter disconnects from the grid and your battery will supply power only to the critical loads panel. This is necessary with many installations because the maximum electrical load of the house is greater than the maximum amperage that the battery can supply. However, you might be able to power your entire house if your maximum load is small enough: for example, if you donât have a central air conditioner or electric stove. Your installer will make this assessment for you.
- Plan for your solar panels to last longer than your battery will. Your solar panels probably have a 25 year power warranty, but your battery will have a 10 year warranty at the most. Itâs possible for lithium ion batteries to have a longer useful life than its warranty period, but you should factor in a periodic replacement cost when calculating the financial impact of adding batteries to your system. This replacement will be more frequent if you opt for lead acid batteries.
How Much Heat Do Solar Panels Absorb
Although solar panels absorb heat much like a roof would, the fact that they are raised up off the roof significantly changes the amount of infrared radiation that makes it into the house. Think of it this way: the solar panel absorbs about 30% of the suns heat energy, re-emits half out toward the sky and half toward the roof, which absorbs about 30% of the heat emitted by the solar panel or only 5% of the sun’s heat . This concept is supported by a study by UC San Diego.
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Mechanism : Energy Conversion
Solar panels turn solar energy into electricity. Residential solar panels generally have an efficiency between 16 – 20%. This means that 16 – 20% of the energy that hits your solar panels isnât reflected or turned into heat, but absorbed by the panel and converted into electricity, which is then carried away as DC current by wires.
In other words, solar photovoltaic panels basically wick away solar energy from your roof, carrying it off to do useful things like power your dishwasher and TV. This means that only about 80 – 84% of the remaining sunlight is left to potentially heat your roof up.
Solar Heat Absorption Rate
Solar heat absorption is a common coefficient used to determine the thermal mass of material. Thermal mass measures the amount of heat that can be stored in a material. Wood has a lower thermal mass than concrete, and solar panels have lower absorption than traditional roofing materials. Solar panels consist of glass, silica, metals, and plastics, all of which are materials with reflective properties.
A Study conducted by the University of California San Diego determined that due to the reflective materials, and being raised away from a roofs surface, solar panels reduce heat absorption of a roof by 38%.
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Do Solar Panels Increase Temperature
On the contrary, solar panels help keep your roof and home cooler, as previously discussed. Exactly how much benefit you get from your solar panels in terms of shading will depend on a number of factors, including: 1) the type of roof you have, 2) whether you have an attic or other room placed directly beneath the roof, as well as 3) the level of insulation and ventilation of your attic.
The type of roof can influence the efficiency of your solar panels at cooling down your home. Most roofs in the U.S. are made from asphalt shingles which can get blisteringly hot during summer. Other types of materials, such as clay and metal also get hot in the sun. To get a substantial temperature reduction, a roof needs to be designed to keep your home cool. Nevertheless, solar panels can help with this a bit.
Overall, theres little doubt that solar panels can help keep your home cooler. Exactly how much will depend on your specific situation. Although the cooling benefit of going solar is likely to be minor, it definitely doesnt hurt. Whats more, solar panels also have the additional benefit of helping your roof last longer. Finally, this cooling potential of solar panels is another reason to go with conventional panels instead of solar shingles, which are installed directly onto the roof, without the gap that may aid cooling.
Financial Incentives Include Battery Systems
If youâre seriously considering a battery system, youâll be happy to know that the 30% federal tax credit also applies to your battery system. This means that the substantial upfront cost of a solar battery is reduced by at least the federal tax credit, and possibly other state and local incentives as well.
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Studies Offer Positive Results For Cooling Solar Panels
This gel is a mixture of carbon nanotubes suspended in polymers.
The gel absorbs water vapor during the night while temperatures are cooler. The researchers discovered the amount of gel needed varied according to the climate.
The results of the gel application reduced the panel heat by as much as 50°F and improved the electricity output of the solar panels by as much as 15%, with one outdoor test producing an improvement of 19%.
Those who live in hot climates can take advantage of the latest technology that offers panel cooling systems. In most climates, even top temperatures will not cause damage but could reduce efficiency.
What problems do solar panels solve?
In environmental terms, solar panels can potentially solve a handful of problems, including 1. Air pollution3. Greenhouse gases4. Reduction in fossil fuel useFor individuals, solar energy allows you to become completely self-sufficient when it comes to your electricity needs and can save you a lot of money in the long run.
What are 3 important uses of solar panels?
Do solar panels give you free electricity?
Once the cost of the array is paid in full, the energy it produces is free. There are ongoing maintenance costs, too, such as annual panel cleaning, etc.
How much will my electric bill be with solar panels?
Do you save money with solar panels?
Solar Offsets The Cost Of Home Cooling
Another primary advantage that a home solar system offers is savings on your electricity bills. This is especially true in the summer when the days are longer and your system is able to generate as much energy as possible. A solar energy system can reduce your utility bills or even eliminate them completely depending on system size.
Summer is a time when utility rates are typically higher and you need to run your air conditioner all day long making solar an especially valuable investment for the free electricity it generates. With solar panels on the roof of your Arizona home in the summer, you can set your thermostat to the temperature you and your family like, rather than what your wallet can handle.
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Do Solar Panels Help Insulate Your Roof
According to a study conducted at UC San Diego Jacobs School of Engineering, rooftop solar panels dont just produce electricity free from emissions, but they also help cool down the roofs of buildings on which they are installed. The researchers found that solar panels helped reduce the heat that reaches the roof by a staggering 38%, keeping the roof about 5 degrees cooler than those parts of the roof that are exposed to direct sunlight.
The findings of this study indicate that having solar panels may also lower your cooling costs, which is another perk of going solar, especially if you live in a hot climate. Solar panels on your roof help shade it and reduce the temperatures in the rooms located under the roof. Roof-mounted panels are also installed with a gap of several inches between the roof and the panel, which permits airflow and helps keep both the roof and the panels cooler. Essentially, having solar panels may reduce the need for using your AC during hot summer days, as well as heating during cold winter nights.
