Solar panels come in different capacities, technologies, sizes, and weights. To know how many solar panels, you need to run your home, you must check your electricity consumption. Usually, we install solar PV systems on the roof to reduce or cut the electricity bill as much as we can.
If you check your last month’s electricity bill, you will find the number of units you used for the month. The units are in kWh. The electricity usage of a household depends on several factors.
It depends on:
• How many people are there in the house?
• What appliances are you using?
• How long do you use these appliances?
How To Calculate Solar Consumption
When there are many people in your house, it is quite clear that the electricity consumption will increase. It is because everyone must consume some sort of energy to do some work. However, the consumption depends on the power consumption of the appliance you are using.
For example, say your iron has a power rating of 2000W. If you use your iron for 2 hours straight, it means you consume 4 units (kWh) of power. Feel like Greek?
This is how do we calculate the power we consume:
2000W = 2000/1000 = 2kW (power in kW)
If you use the iron for 2 hours.
2kW x 2h (hours) = 4 kWh (kilowatt-hours or units)
Similarly, all the units you consume will sum up to the consumption in the electricity bill. Now that we know how to check electricity consumption, let’s see how many panels we need to cover our electricity bill.
Average Sunlight In the UK
According to statistics, the average electricity consumption of a household in the UK is around 10 kWh (units) per day. That means 300 kWh (units) per month.
To calculate the number of solar panels, the next thing you need to know is the number of sun hours you receive in your area.
Solar panels generate electricity using sunlight. Therefore, you need to have enough light to generate electricity using solar panels.
The path of the sun is not constant throughout the year for any country, and it is similar in the UK too.
You get the least sunlight in the UK in winter and the highest in the summer. However, the average number of sun-hours is around 4 hours in the UK. But this value will vary for different regions.
• England: 4.1 hrs
• Scotland: 3.7 hrs
• Northern Ireland: 3.2 hrs
• Wales: 3.3 hrs
How To Calculate How Many Solar Panels You Need
If we assume the consumption of your house is 10 kWh (units), you can calculate the system capacity now. You know that the sun is up for 4 hours on average. Therefore, if we divide 10 kWh by 4 hours, you will get the solar system capacity you need to cover your electricity bill.
10 kWh / 4h = 2.5kW
The standard size closest to 2.5kW is 3kW. You should install a 3kW system on your roof.
Now you can calculate the number of solar panels you need because you know the total system capacity. As mentioned before, solar panels come in different capacities and sizes. The number of solar panels you require for a 3kW system will vary depending on the capacity of the solar panel you use. Many good solar panel brands are selling solar panels with different capacities.
Usually, solar panel capacities vary from 300W to 600W.
If you choose a 300W solar panel:
No. of solar panels for 3kW (3000W): 3000W / 300W = 10 panels
If you choose a 450W solar panel:
No. of solar panels for 3kW (3000W): 3000W / 450W = 6.67 panels = 7 panels
Likewise, you can calculate the number of solar panels for any system capacity you might need.
However, it is important to note that there are a few other factors you need to consider in deciding the right solar panel.
You should choose the solar panel wisely, taking all these factors into account. There are different constraints to homeowners.
Some may have limited space on the roof. In such cases, it is wise to pick a higher wattage. However, when the capacity increases, the cost per solar panel also increases equally.
Some may have a limited budget. In that case, they should be more concerned about the cost rather than other factors.
Whatever brand you select, despite the number of solar panels you install, always make sure that your solar PV installation project is workable.