How Many Kwh Do Solar Panels Produce? (Simple Guide!)

Watts are a measure of how much power your solar panels can produce. The watts you generate depend on many factors, including the size of your solar panel system, the quality of the installation, and weather conditions.

This guide will provide an overview of watts and offer some tips on how to calculate the watts for your solar system.

How Many Watts Do Solar Panels Produce?

The watts generated by your solar panels will depend on some factors, such as:

  • The size of your system (i.e. number of panels)
  • The quality of the installation (i.e. pitch or roof angle)
  • Weather conditions (sunny versus overcast)

These factors will determine how many watts your solar system is capable of producing at any given moment.

The Size of Your System

The size of your system will determine how many watts you can generate. A solar panel with 100 watts is obviously more powerful than a 60 watts one.

However, the most important factor to take into account when understanding watts are the number of panels you have in your system.

For instance, if you have ten 100 watts panels installed vs twelve 50 watts ones, then it’s safe to say that overall your system will be more powerful (producing 1200 watts vs 600 watts).

The Quality of The Installation

The quality of your installation is also a factor that will determine watts. The better the angle at which you install the panels the more watts they will be able to generate per hour.

This is why it’s important to look into hiring an experienced solar company when installing your system. If done wrong, even with the most powerful solar panels, your watts will be significantly reduced.

Weather Conditions

The better the weather conditions, the more watts your solar panels will be able to produce. On a sunny day, you can expect a higher output whereas on cloudy days it might only generate half of the usual amount.

A set of solar panels on the roof of a home but they are covered in a layer of snow.
Cold weather will impact the power output of your solar panels.

That is why it’s very important to consider the weather conditions in your area when planning a solar panel system.

Weather such as rain or hail can also have a negative impact by potentially damaging the solar panels which reduces their efficiency.

How Many kWh Do Solar Panels Produce?

Every solar panel has a nominal power rating. This is in watts, or watts peak (Wp). Multiply this by the number of hours you’ll get sunlight and you have your kWh output for one day.

For example, if you have an 18 watt peak solar panel that will receive six hours of direct sunlight per day, you’ll have an output of 108 watts per day.

Using this method, the average solar panel will produce 0.55 kWh to 0.65 kWh a day during peak sunlight hours (1100 – 1500) or about 30-35 watts for six hours. This number varies according to your geographical location and system design, but it is a good starting point for estimating the watts produced.

It is important to note that solar panels do not produce watts 24/365, so you need to figure out your system’s capacity in kWh per day.

What Are Watts Used For?

Watts are useful for comparing the energy production of different devices or systems.

Watts can help you choose solar panels with a certain power output to match your needs. They also make it easier to compare how much solar energy is produced by one system compared to another at any given time.

Typically watts used per hour are more important than watts produced.

Most people talk about kilowatt-hours (kWh). Kilowatt-hours measure the total energy used over a period of time.

For example, watts used per hour multiplied by hours equals watts-hours (Wh). This is the total energy consumed in one hour from devices plugged into your home electricity system.

How Do You Calculate Watts For A Solar System?

Watts can be calculated by multiplying voltage and current: P=IV (watts = volts x amps).

The maximum watts that solar panels produce is called their rated watts or nameplate watts.

These are the number of watts that you will see written on any solar panel spec sheets you receive from your installer.

Not all solar panels have their actual rating written down. Some companies provide estimations instead such as ‘close to 400W. This doesn’t mean however that these companies aren’t aware of what wattage they actually put out; it could simply mean they haven’t had them tested and still want to be conservative in their estimates.

Why Does Solar System Output Vary from Place to Place

Solar panels only produce power when they are exposed to sunlight. The maximum watts your solar panels can generate is going to vary from place to place depending on a number of factors:

  • A location with more sunshine will produce more watts than one with less
  • Cloud cover can reduce watts produced by up to 20%
  • Snow and ice on solar panels can reduce watts produced by up to 80%
  • The angle at which the panels are set can affect the watts produced
  • Shading of your panels will also cause them to produce fewer watts
Several large solar panel arrays angled towards the sun for maximum power generation.
Angle your solar panels towards the sun for maximum power generation.

The time of day and season also affects the power output for your solar panel installation, for example:

In the summer months, watts produced can be up to 20% higher than in the winter months. In the winter months, watts drop, but this is often offset by cheaper electricity rates.

In the morning hours watts produced are often lower as there is no sun yet but by early afternoon they have typically risen to their highest levels.

In the winter watts are typically at their lowest in the early morning and evening hours while they reach a daily maximum around noon.

Keep all these points in mind when deciding on a location to install your panels.

Can You Increase Solar Panel Output or Efficiency?

Solar panel output cannot be increased since watts are a result of weather conditions and solar exposure, which means that there is no way to change the number of watts being produced by your solar panels.

However, it’s possible to increase efficiency if you have space available or can mount them in a better position for maximum power generation.

To increase the efficiency of your solar panels try the following options:

  • Ensure panels are facing south in order to take advantage of the most natural sunlight
  • Keep your solar arrays clean
  • Birds can damage solar panels by pooping on them, so do not install them near overhanging trees.
  • Ensure your solar panels are angled at the optimum angle for collecting sunlight
  • Try to keep them away from any shade or shadow
  • Install solar tracking systems to increase watts output by up to 20%
  • Use thicker and more efficient electrical wiring such as MC cable to connect all of your solar panel components together. This will reduce watts lost along their path which would otherwise be wasted watts that don’t reach your batteries.
  • Consider getting higher efficiency solar panels to boost power output further if you have space available or are happy with mounting them at a less optimal angle.

Making these changes to your solar setup can provide a significant impact to watts produced.

Do Solar Panels Lose Efficiency Over Time?

Over time solar panels can lose efficiency if they are not properly maintained. Here’s what you need to know:

Solar cells used in most modern solar panels should maintain around 80% of their original watts output for up to 25 years

This only applies though, when the following maintenance steps have been carried out regularly throughout those 25 years:

  • Keep solar panels clean to remove any debris that may have settled on them during storms or high winds which could damage their efficiency. Use a soft brush to wipe all surfaces of your solar cells, taking care not to scratch them as scratches can also reduce watts output over time.
  • Ensure that all electrical connections are kept in place and secure without getting too hot, which could damage them. If the cables feel warmer than usual then they have probably been damaged by heat build-up along their path through your system so consider using thicker wiring instead. Check this is not the case and replace if necessary.
  • Check solar panels regularly for any damage such as punctures, cracks or chips which could reduce watts output over time. Also check wires to ensure they are not loose, frayed or touching anything that may cause them to short circuit.
Homeowner cleaning solar panels with water and a long brush to keep them at maximum efficiency.
Keep solar panels clean for maximum efficiency

If you have done all of the above then your efficiency should remain stable for the next 25 years. If you haven’t, then the watts produced will gradually decrease over time until they reach a point where it is more cost-effective to replace them with new solar panels rather than spending money on ongoing maintenance.

Be aware that watts lost due to damage cannot be returned or replaced, so it’s important to keep your solar panels in good condition over the years and limit watt loss as much as you can.

How Many Watts Do I Need for My Solar Panels?

The watts you need for your solar panels depend on what appliances and devices you would like to power.

The best way to calculate how many watts you need is to add up the watts of all your appliances and devices.

If you still aren’t sure how many watts you need to power all your devices, we recommend contacting a professional installer who can help calculate watts based on measurements taken from the space where you want to install solar panels.

Final Thoughts

In this blog post, we’ve taken a closer look at how many kWh solar panels produce and answered some common questions about solar power.

We hope that after reading this post, you have a better understanding of how solar energy works and why it’s such a great investment for your home. If you have any additional questions, please don’t hesitate to reach out to us.

Now that you know how much power solar panels produce, does your setup have enough power to run specific appliances? If you are interested in finding out how many solar panels are needed to run an air conditioner, read our blog post on the topic.

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