Solar Thermal Panels Vs Photovoltaic Panels
You may find that in addition to the many other choices you have when it comes to solar, you also have two panel types to choose from. Solar thermal and photovoltaic are the two main types of solar energy. For most homes, photovoltaic is the most common type, while solar thermal is typically used for larger commercial settings.
Solar thermal panels use heat, which it then converts to energy. This means it could store the heat from the day and then produce energy at night. Photovoltaic cells produce electricity from light. This is the most common cell because they can be installed with or without batteries, and they do not overheat. Some thermal panels lose efficiency as they heat up, making them not as good a choice for mounting on top of a home or in very sunny climates. Both have a similar cost per watt, depending on the manufacturer.
Other Ways To Measure Your Roof
If you have a proper safety harness, you could go up on the roof and take a direct measurement with a tape measure. Thatâs risky for personal safety, and walking with a heavy foot on your roof can damage your shingles. So I donât recommend that.
Instead, if you have a rectangular section of roof, you could take the measurement from the ground. This should be more accurate than using a tool based on satellite photos.
Take your measurements from the corners of the roof where they meet the ground: Vector art courtesy macrovector_official/Freepik.com
Once you have X and Y, multiply them to get the area on the ground. So, if your X = 25 feet and Y = 12 feet, your area on the ground would be 300 feet². But thatâs not the area of the roof, because it is sloping. We need to do a little trigonometry.
You need to measure the angle of the roof, and you can do that with a smartphone app like Measure for iOS or Bubble Level for Android. Measure comes pre-installed on iPhones, so you should have it already.
Of course, this isnât as accurate as going up on a ladder to take a measurement, but it sure is a lot easier, and good enough because weâre just doing this exercise to get a rough estimate of our panel count.
To take a measurement, stand underneath the roof section you want to measure, and hold up the edge of your phone so that itâs parallel with the roof. Hereâs what it looks like using Measure: Measuring your roof slope from the ground
Cost Of Diy Solar Panels
The cost of DIY solar panels runs $2,000 to $20,000 for a kit ranging from 2kW to 10kW. These kits include everything you need to install your own solar array. However, you may even look to building your own panels.
The costs to make your own system and build it from scratch is going to vary quite a lot depending on you level of skill. Its a highly technical and specialized field. If you have a high level of electrical skills, you may be toying with the idea of building your own solar panels. The cost of solar cells and the silicon wafers used to create them are available to purchase individually. To build your own, you would typically put 60 of these wafers onto a backing and wire each of them. You would then need to connect this to an inverter.
Consider, however, that there are several risks associated with building your own, including:
- You can’t be sure of the quality of solar cells purchased.
- Homemade panels are often a fire hazard.
- Many tax credits and incentives will not apply when systems are constructed outside of approved facilities.
You May Like: How To Get The Best Solar Deal
Few Things About Solar Panel Output Efficiency
Solar panel type and quality make a significant difference in terms of solar output and efficiency. Not all solar panels are the same.
For instance, monocrystalline photovoltaic solar panels are known to be the most efficient solar panels on the market, but also the most expensive.
Their two main advantages over the other types of solar panels such as polycrystalline or thin film panels is that 1) they absorb more sunlight than conventional cells and their output efficiency is not affected that much by temperature and 2) they occupy less space. These are an ideal option if you do not have enough roof space for standard panels.
On the other hand, polycrystalline panels are cheaper, they are less efficient and therefore occupy more space, but offer a better return on investment than monocrystalline panels.
Because of these wide differences in quality and efficiency, its up to you to decide which solar panels are right for your home.
The main takeaway is that, the more efficient the panels are, the more power they can produce, and the fewer photovoltaic panels you will need on your roof to get the same energy output as you would get with polycrystalline or thin film solar panels.
Overall, if money is not an issue, monocrystalline panels are the best option.
How To Calculate How Many Solar Panels You Need
The formula we used to estimate the number of solar panels you need to power your home depends on three key factors: annual energy usage, panel wattage, and production ratios. What does that mean exactly? Here are the assumptions we made, and how we did our math:
Annual electricity usage: Your annual electricity usage is the amount of energy and electricity you use in your home over a full year. Measured in kilowatt-hours , this number is influenced by the appliances in your home that use electricity and how often you use them. Refrigerators, air conditioning units, small kitchen appliances, lights, chargers, and more all use electricity. According to the U.S. Energy Information Administration , the average American household uses 10,649 kWh of electricity per year, so well use that number as the ideal solar panel system or solar array size, which would mean you could offset 100 percent of your electricity usage and utility bill with solar panels . If youre interested in getting a more exact number based on your personal energy usage, check last years utility bills to find out how much electricity you used. Once you have that number, feel free to plug it into the equations below.
Recommended Reading: What’s Bad About Solar Energy
Why Does The Biggest System Not Have The Largest Savings
There may be days throughout the year where you consume more energy than your solar system produces, and days where you consume less. Many electric utilities add up all the excess energy that you generate during the year, and subtract it from your total energy consumption during that year. You only have to pay the difference. This is called net metering.
Some utilities will not give you full credit for generating electricity beyond what you consumed that year. Therefore, to maximize your savings, you want to base your system size on your expected electricity usage, without generating a lot of net excess over the year that you cant use.
Our recommended system size on your order is based on offsetting your current energy usage, determined by the average electric bill that you enter. If you plan to add an electric vehicle or other electric appliances in the future, you may want to consider getting a larger system size.
How Much Does It Cost Total For A 1500 Square Foot House
The typical 1500 square foot house can use around a 6kw solar panel system. The total cost of the panels and full installation can be estimated at about $18000.
To get an estimate for your home and how much you can save, contact a local energy consultant. They can provide you with an installation quote and answer any questions you have about solar systems for your home.
You May Like: How Much Does Solar Heating Cost For A Pool
Do Solar Panels Make Sense For My Home
Some factors, like roof direction, roof shading, the solar inverter you choose, and whether or not youre including a solar battery could also influence the number of panels you need. These factors, however, are hard to quantify on your own.
The best way to determine the ideal location for your home solar power system and how many solar panels you need is by getting quotes from qualified local solar companies. Solar installers will also be able to give you an idea of the upfront costs of solar for your home and what rebates, incentives, and tax credits homeowners in your area qualify for.
In the meantime, using the steps in this article can give you a rough estimate of how many photovoltaic solar panels you need to power your home with clean, renewable energy.
Is going solar worth it where you live?
How Many Solar Panels Do You Need For Specific System Sizes
In our long example at the beginning of this piece, we determined that an 8 kW system would probably cover the average energy use for an American household if you live in an area with a production ratio of 1.6, which might be a realistic number for homes in most parts of California. Lets extend that a little further, and look at a few more examples. In the table below, weve compiled some solar panel estimates for common system sizes seen on the EnergySage Marketplace. Again, the big caveat here is that were using 1.6 as the production ratio of choice. For California shoppers, this might actually be realistic, but for folks in the Northeast or areas with less sun, these estimates might be a bit high on the production end and low on the number of panels needed.
How many solar panels do I need for my house? System size comparison
| System size |
|---|
Also Check: How To Connect Solar Panel To House Electricity
Picking The Right Battery
So, which solar battery is right for you? There are a few different battery types commonly used for off-grid storage systems:
Flooded Lead Acid
- No maintenance, no venting
- Highest efficiency, faster charging, more usable capacity
The two main battery chemistries for off-grid are Lead Acid and Lithium. These two chemistries have unique characteristics. Lithium batteries are more efficient, which means less power is wasted in the charge/discharge process. They also have a greater discharge depth allowing you to fully utilize all of your battery capacity.
Lead acid batteries are sensitive and need to be fully recharged every day, where Lithium batteries can stay at a partial charge without any adverse effect. Lead acid batteries also have a more limited amount of usable capacity and are typically discharged only 50%.
Because of the better efficiency and deeper discharge depth, Lithium battery banks tend to be only 50-60% of the size of a comparable lead acid bank! The Lithium batteries we use are purpose-built for off-grid solar, and utilize a special Lithium chemistry called Lithium Ferro Phosphate .
This type of Lithium battery is engineered to provide a long service life while also being safe, with a stable chemistry and sophisticated electronic protection features.
| 55.2kWh: 1150ah 48v Sealed LA 57.6kWh: 1200ah 48v Flooded LA |
This is not intended to be a comprehensive guide on off-grid design.
The Climate Of Your Area
Well, as you might imagine, a home in a temperate climate uses less energy than somewhere colder or hotter.
In hot climates, fans do not suffice, and people turn to A/C to have a comfortable temperature around.
So, having the A/C on for most of the day will consume more energy than with a fan, right? So, having A/C at home means that you will need to install more solar power.
A small home in a mild climate area uses around 200 kWh per month. But if you go south where the A/C power demand occupies a large share of the energy consumption, that figure could go up to 1700 Kwh.
Same story goes to heating.
Read Also: How Much Does It Cost For Solar Panels
How To Get Your Affordable Solar Energy Today
The first thing you want to do is figure out your energy use and how to improve it.
You can do this by contacting your electric company for your detailed power usage in kWh over the last year. And you can hire a home energy auditor to do an inspection of your home to help you see where youre losing money on energy.
After you know how to maximize your energy use, start getting quotes on solar from your local solar professionals.
Your solar professional will be able to help you maximize your solar panel system with the right size, panels, mounts, inverters, etc. And theyll be able to help you get the permits and access the incentives and subsidies your state or city offers.
Homeowners who explore their options thoroughly with Home Professionals, comparing several quotes, could save thousands on their solar installation.
To take advantage of this help, please call our number or use our free pro and quote finder below. Home Professionals will get you connected the the best deals and pros in your area.
Electricity Usage For Home Heating
In some places in the United States, you might need home heating only a couple weeks a year. This includes the South Atlantic and Gulf Coast regions, and southern California. For those situations, electric resistance heating tends to be used much more than in states that have several months of heating days.
Electric resistance heating uses electricity to heat a coil, like in a toaster or hair dryer. Youâre probably familiar with electric baseboard heaters or small space heaters. Electric resistance heating is inefficient, but itâs handy in regions with low heating requirements, because itâs cheap to install and doesnât require ductwork.
In cold-weather US states with multiple heating months, natural gas is the most popular heating fuel. While a gas furnace does use some electricity to power the fan, itâs a fraction of the power that would be needed for a fully electric furnace.
Note that electric resistance heating is different from highly efficient electric heat pumps, which use electrically-driven compressors to pull heat from the air or ground, much like the way that a refrigerator or air conditioner works. Heat pumps are becoming more popular, even in very cold climates. Many utility companies and local agencies offer rebates on both air source and ground source heat pumps.
Recommended Reading: How Much Is One Solid Gold Bar Worth
Monocrystalline Silicon Solar Cells
The cost of monocrystalline solar panels averages $0.60 to $1.20 a watt uninstalled. This is the most expensive but most efficient solar panel type. It is highly aesthetic and works well in a variety of applications. This panel type is made up of cells that are formed from whole silicon crystals. The whole crystal, rather than the fragments that make up polycrystalline, makes these panels much more efficient. It also makes them longer-lasting in some applications.
How To Determine How Many Solar Panels You Will Need
Taking into account the factors in the section above, a simple formula to use to estimate the size of the system that you need is kWh per year / 1200 = the size system you need . Our actual system design will take many other factors into account, but this should be a good estimate. Once we have the kW needed, we will select the number of panels by reviewing your available roof space and your target budget. For example, if space is an issue, we will need to select a higher efficiency panel to keep the footprint small and the production high. Likewise, a cheaper panel could be selected if there is more available space to work with.
You can do the math or better yet, use the examples we compiled for you to get a ballpark idea of the number of panels youll need. We suggest contacting a solar installation professional to determine the exact size for a system that best fits your needs. In the meantime, this chart is a good reference point.
| Average Monthly |
Note: A 330W solar panel covers roughly 19.5 sq. ft.
Homeowners
Most homeowners will need a 5 kW to 20 kW solar system. This would obviously vary depending on a few factors, such as: if you have a heated pool or use electric heat.
A $120 average monthly electric bill will need a 10 kW solar system to cover their annual energy usage. A 10 kW solar system will utilize 32 330W solar panels and cover roughly 624 sq. ft.
Businesses
Recommended Reading: What Is Fpl Solar Now Program
How Does Sunlight Amount Affect Solar Panels
Different areas of the United States receive more or less sunlight compared to other areas. The amount of sunlight you receive directly correlates with how many solar panels you will need.
Typically, southern states get more sun than northern states. But southern states with higher altitudes and less cloud coverthink of Arizona and New Mexicoget more energy from the sun than states such as Florida or Georgia. So, for the same size house, you would generally need more solar panels in Georgia than you would in Arizona.
Remember, the sun may be shining, but if it is behind a cloud, youre not getting the same amount of solar energy absorbed by your solar PV system. This means that a solar panel in San Diego will produce more energy in a year than the same exact solar panel located in Seattle.
The image below will help you determine the solar energy, known as solar insolation, in your area. Exploring your sun number score should also be helpful. If your roof does not get a good amount of sunlight and you live on a good size amount of land, you may have other options for mounting solar panels elsewhere with better sunlight.
