How Many Solar Panels Do I Need?

How many solar panels do I need?

How Many Solar Panels Do I Need?

How many solar panels do I need?

Determining the number of solar panels required for your energy needs is a crucial step in the solar installation process. Many factors come into play when calculating the ideal number of panels, and understanding these factors will help you make an informed decision. In this article, we will guide you through the process, taking into account the unique considerations of solar panel installation in Singapore. If you do not like calculation, you may use our solar calculator to obtain an accurate estimate. Additionally, reputable solar installers like LHN Energy can provide valuable guidance tailored to your specific requirements.

1. Evaluate Your Energy Use

To get started, gather your past electric bills. This historical data will serve as a baseline to estimate your energy consumption. Look for the total kilowatt-hours (kWh) of electricity used per year. By analyzing your past energy usage, you’ll have a solid starting point to determine the number of solar panels you’ll need.

What is kilowatt-hour (kWh)?
What is kilowatt-hour (kWh)?

A kilowatt-hour (kWh) is a unit of measurement used to quantify energy consumption. It represents the amount of energy consumed or produced over the span of one hour by an electrical device or system with a power output of one kilowatt (1 kW).

By understanding the concept of kilowatt-hours and calculating the energy consumption of various devices, you can evaluate your overall energy usage and estimate the number of solar panels required to meet your electricity needs.

2. Calculate Daily Energy Usage

Divide your total yearly energy usage (in kWh) by 365 to obtain your average daily energy consumption. This figure will be instrumental in determining the capacity of your solar system.

3. Assess Sunlight Availability

According to the Energy Market Authority, the average duration of sun peak hours is approximately 4.3 hours. Sun peak hours refer to the period of the day when solar energy generation is at its highest, making it a crucial time for harnessing solar power efficiently.

4. Consider Solar Inefficiency Factors

Solar panels can be affected by various efficiency-reducing factors, including shading, tilt angle, orientation, and panel efficiency. Singapore’s tropical climate and the presence of high-rise buildings may cause partial shading, impacting the overall output of your solar panels. Conducting a thorough site assessment is essential to identify potential shading obstacles and optimize panel orientation and tilt angle for maximum sunlight exposure.

It’s also important to consider the derate factor or performance ratio of your solar system, typically ranging from 0.75 to 0.9. This factor accounts for various performance losses, such as shading, dust, soiling, wiring losses, and inverter efficiency. By factoring in these inefficiencies, you can calculate the number of solar panels needed to meet your energy requirements.

Once you have all the necessary numbers, use this formula to estimate your total system size:

Calculation method to calculate how many solar panel needed

For example:

Let’s assume the average annual electricity consumption for industrial building is 1,000,000 kWh, resulting in approximately 2,740 kWh per day (after rounding up).

This estimation provides an approximate system size of 796.51 kW, or 796,511 W (remember, 1 kilowatt = 1000 watts).

The next step is to divide this system size by the energy rating of each individual panel. Solar panels are graded by their power output. Panels used in an industrial setting typically range from 455 to 600 watts per panel.

Let’s assume we want to use 540W panels. Divide your system size by the panel wattage to determine how many solar panels you need in your system:


Determining the ideal number of solar panels for your installation involves evaluating your energy consumption, considering sunlight availability, and accounting for solar inefficiency factors. By analyzing your historical energy usage, calculating daily consumption, and factoring in the unique conditions of your location, you can estimate the number of panels needed to generate sufficient electricity. Collaborate with LHN Energy and we will ensure a successful solar installation that maximizes energy production and promotes sustainability.