Solar panels are devices that convert sunlight into electricity. They are made up of multiple solar cells that are typically made of silicon and generate direct current (DC) electricity when exposed to sunlight.

Rooftop of a house installed with solar panels

According to modern research based on average electricity consumption and peak sun hours it takes around Seventeen 400-watt solar panel plates to power a house. However, this number will vary between 13-19 based on how much sun the panels get and how much electricity the home uses.

The amount of solar panels that a house needs to be powered is based on a lot of factors. Factors include Energy Usage, Orientation and Tilt, Roof Space, Panel Efficiency, and Budget.

Here is a detailed overview of the key points that are mentioned above if you are looking for what size solar panel you need to power your house.

Energy usage:

The first thing that you need to consider is your monthly energy consumption. You can find your monthly energy consumption from your electricity bill. It shows all the energy your house is consuming over the month.

Another way to find out your energy usage is with the help of a Kwh calculator. This kWh calculator makes estimating your home’s electricity usage easy. Whether you live in a small unit or a large house.

The calculator will provide an approximate monthly kWh usage amount. This estimate accounts for factors like home size, number of people, and consumption behaviors. This is how it works all you need to do is enter some minor house details like home square footage, number of occupants, and your energy habits (low, average, high usage).

If your home is over 2,000 square feet, your electricity use may be higher. As a general reference, here are estimated monthly kWh usage ranges based on home size:

  • 2,500 sq ft – 1,250 to 2,500 kWh
  • 3,000 sq ft – 1,500 to 3,000 kWh
  • 3,500 sq ft – 1,750 to 3,500 kWh
  • 4,000 sq ft – 2,000 to 4,000 kWh
  • 4,500 sq ft – 2,250 to 4,500 kWh
  • 5,000 sq ft – 2,500 to 5,000 kWh

You need to remember that your actual usage depends on many factors like weather, number of occupants, appliances, and more.

Roof Space:

The available roof space for solar panel installation is also a key factor that impacts the size of the solar system you can install. You need to consider the size and shape of your roof. You need to see if your roof is big enough to accommodate the number of solar panels you’ll need also you need to see if there are any obstacles (trees, chimneys, etc.) that could block the sunlight from reaching the panels. The angle of your roof and the direction of your house also play a vital role in the efficient working of your solar panel.

A specialist installing solar panels


You will use a solar roof calculator and the calculator will tell you how many 100-watt, 300-watt, or 400-watt solar panels you can put on your roof. When you have calculated how many of either 100-watt, 300-watt, or 400-watt solar panels you can put on roofs ranging from very little 300 sq ft roofs to huge 5,000 sq ft roofs, summarize the results in a neat chart.

Panel Efficiency:

Solar panel efficiency is a very important factor to consider when evaluating the performance of a solar energy system. This panel efficiency refers to the ability of a solar panel to convert sunlight into usable electricity. Calculating solar panel efficiency involves comparing the amount of sunlight that hits the panel to the amount of electricity it produces. By determining the efficiency, you can evaluate the effectiveness of your solar panels and make informed decisions about their installation and usage.

Solar panel efficiency refers to the percentage of sunlight that a solar panel can convert into usable electricity. Higher numbers mean more electricity is generated from the same amount of sunlight. Several factors can influence performance, including solar cell material, temperature, angle and orientation, and dust and debris. Good photovoltaic panels are crucial for the overall performance of a solar power system, leading to cost savings and a reduced environmental footprint. Know the module’s power capacity. It should be generating electricity based on its capacity if not then the solar panel will not work efficiently.

A very important way of knowing solar panel efficiency is the Solar panel efficiency formula. Here the formula will show how to calculate solar panel efficiency

Solar Panel Efficiency = [ Solar Panel Max. Output P(max) ÷ (Solar Panel Area In m² × 1000) ] × 100

Orientation and Tilt:

Solar panel orientation refers to the direction solar panels face. It is a crucial factor in their efficiency. Selecting the right orientation for your solar panels revolves around cardinal points. In the northern hemisphere, south-facing panels are usually the best choice, while in the southern hemisphere, north-facing panels are ideal. However, east and west-facing orientations can be suitable if you have specific energy production requirements. The tilt and angle of solar panels are key factors in influencing how much sunlight they receive.

Throughout the day and the year, the sun’s angle and direction fluctuate. To guarantee that the panels receive the most sunlight possible it is important to tilt them and align them in the best possible ways. An improper tilt or orientation can lower energy output substantially and raise energy expenses.

Solar Panels situated on a rooftop

The installer will estimate the number of solar panels that you need to install in your house but for your own knowledge here is another method to determine the number of solar panels that you need to power your house. Use the equation below to get an estimate of how many solar panels you need to power a house.

Daily Electricity Consumption/Peak Sun Hours/Panel Wattage = Number of Solar Panels