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What You Need to Know About Solar Panel Sizing
Ontario is currently ranked 9th in the country for installing a solar panel power system, scoring as one of the best provinces for upfront installation costs and financing options in the country – not to mention, they are environmentally friendly and represent a sound investment opportunity as compared with many other electricity sources – check out the Complete Guide to Solar Panel Sizing for Your Home.
Although the sun’s energy is a renewable and sustainable source of power, it’s important to make sure you’re using it to its fullest potential. Therefore, you’ll want to size your solar panel system correctly to ensure that you are getting the most out of your system. This will make sure you have enough energy without it being unnecessarily expensive, by accidently oversizing the system for your home.
Figuring out the proper size of a solar panel system, in terms of how many solar panels are required, is one of the most frequently asked questions to date. That’s why the experts at SolarUP have created this guide to help you properly determine the correct size of solar panel system that you’ll need to efficiently power your home.
As there are many factors to consider when determining the size of your solar panel system, such as calculating the solar needs of your home, estimating the size of your system, and selecting the panels that will allow you to obtain the most out of your solar panel installation, all of which will be outlined for you in this article.
How to Determine Your Solar Panel Needs
Solar panels are a great way to generate your own renewable energy. But before you go out and buy the first set of solar panels you see, make sure you do your research and calculate your needs to ensure that they will be the best solar panels to use for your home.
There are many factors that can affect how much power your home needs, such as square footage, number of people living in the house, along with the different appliances used in the house. This can be difficult to calculate without some help, so it is important to find a reputable company like the solar power technicians at SolarUP who will walk you through this process.
It can be estimated that an average house needs anywhere from around 20–25 solar panels to cover basic electricity consumption needs. Although, if you’re looking to calculate the exact number of panels that are required to efficiently power your home, these factors must be considered: the amount of energy you need in your home, the amount of sun peak hours (HSP) in your geographic area, and the power rating of your solar panel.
NOTE: It’s important to note that the number of solar panels you might need to supply enough power to your home directly impacts the price that you will pay for solar.
What Is Your Home’s Electricity Consumption?
When looking at determining the energy consumption of your home, there are two primary ways to go about it. The first being, merely looking over your utility bill, where you’ll find the number of kilowatt-hour (kWh) that you use per month and per year for your home. Whereas, if you want to know the average daily usage for your home, you need to divide the annual value by 365. Alternatively, you will also be able to check the energy usage details on your utility website.
The second way is more complex, in that it requires you to estimate the power demand and the hour of consumption for each device in your home – such as refrigerators and air conditioning units – to obtain the energy consumption. The amount of power a photovoltaic panel will generate depends on both the quality of the panel and how many hours per day it is in direct sunlight. The general equation for this calculation is generally performed by a design off-grid system.
It’s important to take into consideration that the electricity consumption varies depending on your location and the habits of usage for which your home exhibits. For instance, if your home is in geographical areas that are known to be hotter (located to the south) you are more likely to consume a lot of energy towards air conditioning. Meanwhile, if your home is in colder geographical areas (located to the north) you are likely to consume more energy in heating units throughout the winter. This is a particularly important aspect to take into consideration for sizing an off-grid system for your home.
Where is Your Home Located?
As mentioned above the geographical location of your home is essential for properly sizing your solar system; regarding the number of solar panels needed for your home. Considering the location of your home, in terms of level of sun exposure, will be a determining factor, in terms of whether you will need fewer or more panels.
Solar panels function more efficiently when they are exposed to direct sunlight. This usually occurs during peak hours of sunlight. And so, depending on your geographical location the peak hour of sunlight may vary. The impact of peak hours of sunlight can be directly translated to the amount of energy that is produced by your solar panels.
The definition of a peak sun hour (HSP) is referred to as the number of equivalent hours that have an irradiance value of 1000 W/m2, which is close to the maximum irradiance value that can be attained on a surface on Earth. However, it’s important to note that the HSPs do not mean the same thing as the number of hours of sunlight seen throughout the day. As such, depending on where your home is located, it is possible that it may receive anywhere from 6-8 hours of sunlight a day. Although, the number of peak hours of sunlight obtained is closer to 4.
How Many Solar Panels Does Your Home Need?
To calculate how many solar panels you need for your home, you need to know the size of your roof and the number of hours of sun it gets per day.
Solar panels are a great way to generate renewable energy and help in saving the environment. However, not all homes can make use of solar panels. It is important for homeowners to know how many solar panels they need for their home before investing in this technology.
Solar Panel Sizing
To properly determine the size of the solar power system required, the most significant factor is determining your energy consumption during a single year. As stated earlier, your monthly hydro bill highlights what your average energy intake is in kWh. Once this has been determined, you can calculate your annual energy usage by adding up the amount illustrated over a 12-month period.
NOTE: It is recommended that you don’t make the mistake of multiplying a single month by 12, as electricity usage can fluctuate greatly depending on the season.
To calculate the size of the solar power system that you’ll need, you can use the following equation:
Size of system needed (kW) = yearly energy use (kWh) / annual equivalent full sunlight hours (h)
(Annual average ‘equivalent full sunlight hours’ in Ontario = 1,166 h)
For example, when adding up your year-end hydro bills, you determined that your home uses approximately 10,000 kWh in electricity over the course of a year. Using the above equation with your consumption amount divided by the annual sunlight hours, you will require an 8.58 kW solar panel system for your home.
10,000 kWh / 1,166 h = 8.58 kW – Size of solar system in units of kW
Physical Sizing
Now that you understand how the system functions in units of kW, you can move forward with determining the physical sizing requirements of your residential solar panel system. In terms of how much space the system will require, you can determine the physical sizing by converting it to units of square feet (sqft).
On average a single solar panel is approximately 18 sqft in size (this includes some buffer room for racking and spacing, which is required for installation) and produces around 300 watts of power.
The equation used to determine the physical space that your solar system requires, can be calculated using the following equation:
Physical space required = size of system needed (in kW) / size of panel (in kW) * physical size of panel (in sqft)
(Average size of panel = 0.3kW, average physical size of panel = 18 sqft)
Using the previous example listed above for determining the size of your solar system in units of kW = 8.58 kW, you would then input the above calculation to determine the square footage you would need to install your solar system to your home, which would be 515 sqft.
8.58 kW / 0.3 kW * 18 sqft = 515 sqft
(Note that 300 watts equals 0.3 kW)
If you’re installing a residential solar panel system on your roof, you should know that:
- A North facing roof is the least effective, East and West facing panels are determined to be mediocre. However, for optimal performance you should have your panels facing South.
- Depending on the condition of the roof of your home, you may need to consider replacing your shingles (or potentially the entire roof) before installation – because panels are guaranteed for up to 25 years!
In cases where you are installing solar panels on the ground of your property, you should also be aware that:
- These systems tend to be more expensive upfront, due to trenching, piling, and mounting requirements.
- These systems also tend to be more efficient. Considering, you can easily determine where they should be placed for optimal direction (South), the optimal angle (~45°), and to avoid as much shade as possible.
- Lastly, ground solar panels systems are more efficient and have better lifetime IRRs and NPVs.
Most residential homeowners in Ontario have solar panel systems installed on the roofs of their homes, given the limited space provided by inner city property restrictions. Although, rural property owners have been known to install systems on both the roofs of their houses or shops – or in cases where there is more land available for use, on the ground in their yards.
The Ultimate Guide to Getting Started with Solar
At the end of this article, we hope you’ll gain a better understanding of how you can determine what size of solar panel system is right for you and your home. Before you go out and purchase the first solar panels you see on the market. As such, if you’re considering getting solar panels installed for your home or business, we highly recommend that you take the time to do your research before making any big decisions.
Nonetheless, we understand that this can be a difficult process to undergo. So, it is important to have a reputable company like the experts at SolarUP to help walk you through the process and ensure you get the most out of your solar panel system.
