Now that we know the key components, let’s break down the process of estimating the amount of solar panels for your roof:

1. Calculate Your Energy Consumption

First, you need to establish how much energy you consume. Look at your power bills to discover your typical monthly or annual use in kilowatt-hours (kWh). If you would like to determine your monthly use, add up the total kWh for each month of the year and divide by 12.
For example, if you consume 1,200 kWh every month, your annual consumption is 14,400 kWh (1,200 kWh x 12).

2. Determine the Solar Panel Wattage

Next, figure out the wattage of the solar panels you want to install. Solar panels generally range between 250 to 440 watts per panel. Let’s say you’re utilising 440-watt panels for this example.

3. Calculate the Energy Production per Panel

Each solar panel produces a specified quantity of power dependent on its wattage. To determine the energy output of a single panel, you need to account for the average amount of solar hours your location gets. Let’s say you receive 5 hours of direct sunshine every day.

If you’re using 440-watt panels:

• 440 watts x 5 hours = 2,200 watt-hours (2.2 kWh) per day per panel.

4. Calculate the Number of Panels Needed

To determine how many panels are necessary to satisfy your energy demands, divide your total yearly energy usage by the annual energy output of a single panel.

For an annual usage of 14,400 kWh, and each panel generating 2.2 kWh each day:

2.2 kWh/day x 365 days = 803 kWh per panel each year.

Divide your yearly use by the energy production per panel:

14,400 kWh ÷ 803kWh = 17.93 panels.

Since you can’t put a quarter of a panel, you would require 18 panels.

5. Adjust for Roof Space and Efficiency

Once you have the fundamental figure, take into consideration the available area on your roof. If your roof is tiny or has shading concerns, you may need to increase the quantity of panels or choose for more efficient ones.