How Many Solar Panels Do I Need For 1000 kWh Per Month?

An average home would require between 20 and 25 solar panels to produce 1000 kWh of monthly electricity. However, this is just a rough estimate and can change based on several factors, like how much solar power the panels can generate.

In this guide, we’ll show you exactly how to calculate how many solar panels you need, as well as what impacts your panel efficiency.

How To Calculate The Number Of Solar Panels Needed For 1,000 kWh Per Month

There are some important factors to consider when calculating the number of solar panels you need to generate 1,000 kilowatt hours (kWh) per month. These include your available sunlight hours and well as the size of the solar panels.

Energy consumption

How much energy you need can vary, but a typical small household would use an average of 1,000 kWh per month. Electricity consumption can increase, and when installing solar panels, you should also consider future energy usage. For example, if your family expands or if you have guests over.

Sunlight hours

How many sunlight hours your area gets is imperative to calculating how many solar panels you need. Some areas get more sunshine than others and will require fewer panels.

Solar panel sizes

Most residential solar panels’ power ratings are between 100W and 400W. You will need more solar panels if they have less power they have. Additionally, more efficient panels can generate more power with less sunlight, reducing the number of panels needed.

System derate factor

Every solar system experiences some energy loss, which is called the derate factor. It is generally added to the total number of solar panels needed to ensure you are well compensated for energy loss from shade or dirt on the panels.

The formula

Calculation: Monthly kWh usage ÷ (monthly peak sun hours x panel wattage x system derate factor) = number of solar panels.

Example: 1,000 (monthly kWh usage) ÷ (150 [monthly peak sun hours] x 0.3 [panel wattage] x 0.8 [system derate factor] = 28 solar panels.

If you get more sunlight hours or have higher-efficiency panels, it can change how many solar panels you need.

Example: 1,000 (monthly kWh usage) ÷ (150 [monthly peak sun hours] x 0.4 [panel wattage] x 0.8 [system derate factor]) = 21 solar panels.

Factors That Influence Solar Panel Output Efficiency

Solar panel efficiency is a determining factor for how many solar panels you need. However, other factors can affect their energy output, which could increase the number of solar panels required to fulfil your energy consumption needs.

Shading

Shading from buildings or foliage greatly affects how much solar power can be generated. Shading on even one of the panels can affect the entire solar array by reducing its efficiency.

Dirt and debris

If you live in an area with a lot of wind and dust, your solar panel system may get dirtier more often. This can affect their output efficiency.

Temperature

High temperatures are not best suited for solar panels. Solar panels are most efficient when the temperatures are around 25°C.

Inverters and wiring

The solar panel system setup can also contribute to energy loss. There may be a slight loss of power during the inversion from DC to AC. Also, if your wiring is old and damaged, or if there is resistance in the wiring, it can cause inefficiencies.

Roof angle

The angle of your roof and how much roof space you have available can also affect your total solar panel system configuration and layout. The angle and orientation can also affect the total output and efficiency. A south-facing roof, or an east or west-facing roof, is typically ideal for solar installations. North-facing roofs are less suitable.

Panel age

Solar panels will slowly lose their effectiveness as they age. They do have a long lifespan, lasting between 25 and 30 years, but as they get older, they will become less efficient.

FAQs

How many solar panels are needed for 1 MW?

To generate 1 MW of electricity, you typically need between 1,666 and 4,000 solar panels. The exact number depends on factors such as the wattage of each panel, the amount of sunlight your location receives, and any shading that might impact efficiency. Check out our in-depth article on the number of solar panels you would need to generate 1MW of electricity.

What happens if my solar panels generate more electricity than I use?

If your solar panels produce more power than your energy consumption in a month, you could sign up for net metering. This is a system whereby you send your excess energy back to the national grid and receive credits on your monthly electricity bills. Or you can store the extra energy in batteries so you have it available when you need it.

Can I add more panels to my existing solar system?

Yes, it is likely that you can add panels to your system. However, you would need a qualified installer to assess your current setup. If you just need more power, it may be an option to look at higher-wattage panels instead of increasing the size of the solar panel system.

Do solar companies add in the derating factor for my energy consumption?

Solar companies would factor in the derate factor for your energy consumption in order to give you the correct number of solar panels to accommodate your energy needs.

Final Thoughts

If you want to move away from relying on the national grid or if you just want to reduce your monthly electric bill, it would be worth installing solar panels to produce electricity.

Contact us for a free solar panel installation quote and a move to clean renewable energy. We will provide you with an accurate assessment of your solar requirements and how many panels you need.