How Many Solar Panels Will I Need?

How Many Solar Panels Will I Need?

How many solar panels do you need to provide the energy needed to maintain your home and family? This is a big question as it directly affects the cost of your new solar energy system. Even if the prices of solar panels have dropped in recent years, you still don't want to overpay.

Here is your 8-step process for determining how many solar panels you will need to produce the energy you want.

Step 1: Review your bills, and see how much you have paid, especially the energy you used (kWh).

Step 2: Think about how your future energy needs will evolve in 10 to 20 years.

Step 3: define a solar energy production objective.

Step 4: review your goal with excess energy in mind.

Step 5: Divide the monthly electrical consumption by 30 days.

Step 6: Calculate the power of your solar energy system.

Step 7: Get a solar quote for the ideal size of your system.

Step 8: Find the number of panels for the power you are considering.

6 Factors That Determine How Big Your Solar Energy System Should Be

When planning the installation of a new solar power system, here is a helpful list of the six key factors that affect the number of solar panels your home, farm or business will need.

Factor 1: your monthly and annual electricity bill

Step 1: Go look at your bills – and see how much you’ve been paying.

This is the first thing to look at. It forms the basis for your solar energy production goals.

Taking this type of inflation into account should be part of your thinking. Your savings from solar power will increase over time, even if your usage does not change.

Factor 2: Your Monthly and annual Power Usage

Your usage is shown in kilowatt hours - or kWh. Look for it on your electric bill.

Use is separate from cost for the reason stated above. Your usage may not change much for ten years, but the cost per kWh will change. This is important because the solar panels produce a certain amount of kWh, and that amount will not change much. So even if the costs increase over time with a traditional diet, your use is not necessary. In fact, with better energy efficiency, your consumption could actually decrease.

You need to think about how your life circumstances might change in order to increase or decrease your energy consumption.

Step 2: Think about how your future energy needs will evolve in 10 to 20 years.

If you produce an average of 500 kWh per month now, this may be as high as 600. Or if you plan to move into a new, larger house and want to install solar panels in it, that larger house will likely require more energy usage. Again, plan accordingly

Step 3: define a solar energy production objective.

How much energy do you want to produce from the solar? 70%? 50%? As much as you can afford? All?

You want to know this because it is ultimately what determines how many solar panels you will need. And knowing your kWh consumption is key. If you use 1,200 kWh per month and want to produce 80% of it from solar panels, you will need a system that generates 960 kWh per month.

Keep your goal number in mind when we consider the following four factors.

Factor 3: the number of solar panels you need is affected by the amount of energy you want in summer and winter.

Understanding this is important for several reasons:

What happens if your system produces excess energy during the summer months?

Does your utility grid have a net billing program (solar buyback)?

Do you have a way to store extra energy (solar battery storage)?

If you don't want to buy battery storage, and you can't resell it to the network because your utility doesn't allow it, then producing more power than you need is useless.

This is why many people have set a goal of less than 100%. If your goal is to produce 70% of your energy needs from solar, it is unlikely that you will generate more than you need, even in summer. And instead of having a zero electricity bill, you'll only have a much smaller one. But you will avoid the risk of producing energy that does not benefit you.

However, if you have access to some sort of buy-back or net-billing program, or if you want to buy solar battery storage, then setting a target closer to 100% is more logical.

What's more, if there is a bonus for reselling to utility software grid, then setting as much as you can install is reasonable.

But be aware that your solar panels will not produce constant amounts of energy throughout the year.

Step 4: review your goal with excess energy in mind

Factor 4: your daily energy consumption - kWh per day

Step 5: Divide the monthly electrical consumption by 30 days.

Review your electricity bill again. If you use 900 kWh per month, this represents 30 kWh per day. You will want this number to help you determine how many solar panels you will need.

Factor 5: Average daily sunlight

It's a big problem. A similar size solar panel in Europe will produce far less energy than a solar panel in Saudi Arabia. The reason is that they don't get as much direct sunlight - and not just because of the cloud cover. They are also at a different position on earth, which means that the angle of the sunlight hitting Europe is smaller than the angle hitting the Saudi Arabia.

What is "direct sunlight?" It is sunlight hitting a certain place without interference or obstruction.

Most of the world, gets average about 5 hours of direct sunlight per day. Here, it’s actually highest in the spring and early summer. But the winter has the least amount.  We can get the exact number on NASA or our website.

Step 6: Calculate the size of your solar power system.

You already have the necessary information to perform this operation if you have completed the first 5 Steps. Here is a simple equation to use.

Normally, the efficiency of the solar power system is 90%, and less if you using solar battery storage.

KWh per month / (average sunshine per day * 30* efficiency) = kW solar system

For example, if you use 1000 kWh per month and 5 hours of sunshine on average per day, on grid system , it would be 1000 divided by (5 * 30* 90%) , or 1000/135 =7.4 kW

Thus, to provide 1000 kWh per month in a location that receives 5 hours of direct sunlight per day, a solar energy system of 7.4 kW would be required.

For comparison, producing as much energy in a place with only 3 hours of sunshine a day would require a 12.3 kW solar system - almost twice as big.

Now you have real information and you can use it to get quotes from solar panel installers like us. They can quote you on a 7.5 kW solar panel, for example.

Factor 6: Power of the solar panel - Real energy production BY PANEL

Different panels produce different amounts of energy. And that is why answering the question of how many solar panels a house, business or farm will need cannot be answered by everyone at once.

The solar panels on the market today range from 30 watts to 420 watts. We only suggest 250W to 420W, the higher the better, especially at same size, which means efficiency.

Step 7: Get a solar quote for the ideal size of your system.

If you have a small roof, you will probably want high efficiency panels because you don't have the space for tons of them. However, higher power panels are more expensive. However, ask for a quotation by watt, and choose the lowest model.

Step 8: Find the number of panels for the power you are considering.

Now you know the size and power of your panels, take 375W as example, then use 7.5kw divide 375W (don’t forget multiple 1000 for kW).

7.5*1000/375=20 pcs of solar panels.

So to install a 7.5 kW solar energy system, which will produce 1000 kWh per month in 5 hours of direct sunlight, we will have to buy twenty 375 watt solar panels, or twenty 400W for 8kw system.

If you don't want to buy 375 watt panels, recalculate using 250 watt. 7500 divided by 250 is equivalent to 30 panels.

Now you got it .