How Much Solar Power Do You Need?

by | Apr 23, 2021 | Solar, Solar Sizing

Choosing a solar power solution is a great way to generate electricity for your home or business while saving money and doing your bit for the environment. But how much solar do you need to power your specific home?

The size of your building, the activities that go on inside it and the machinery and equipment that you use on a regular basis are all factors that contribute to your total daily, weekly and monthly electricity consumption. 

In this article we’ll show you how to calculate the amount of power that your home requires and 
choose a solar energy system to suit your needs

alt="Image of electricity consumption in a home to determine solar power requirements"
Energy Consumption of a 3 Bedroom House in Bryanston

Every kilowatt adds up

Have you ever compared electricity bills with your friends or family and found yourself wondering why your consumption is so much higher or lower than someone else’s? 

Many of us incorrectly assume that our monthly electricity costs are determined by the size of our homes alone but in reality, it’s the number of electricity consuming items and devices we have (and how often we use them) that contributes to the total cost of electricity.

  • The amount of power that a certain electrical device uses is measured in kilowatts. Some household appliances such as fridges and freezers use a lot of energy per hour while others like modems and Wi-Fi routers use relatively little electricity. 
  • Modern appliances are designed to save electricity and consume fewer kilowatts per hour while older devices tend to be power guzzlers.
  • Using solar power for your lights, appliances and other devices that you use daily and installing solar for your geyser can help reduce your power bill dramatically. 

The table below shows electricity consumption for a variety of household devices. Much like a calorie counter or nutrition facts on a food label, you could use a table such as the one below to do an electricity consumption audit on the most used electrical appliances in your home.  Bear in mind that the energy usage changes according to the size and output of the appliance.

ItemWattsElectricity Usage (kWh)
Washing Machine23002.3 per load
Fridge160050 per month / 1.6 per day
Aircon18001.8 per hour used
Oven23002.3 per hour used
Dishwasher1000-20001-2 per cycle
LCD TV160.016 per hour used
Laptop300.03 per hour used
Vacuum Cleaner7500.75 per hour used
Geyser92409.24 per day
Freezer1100.11 per hour
Wifi Router12.50.3 per day
100w Incandescent Light1000.1 per hour used
Swimming Pool Pump1501.5 per hour used
*Indicative electricity usage for general household appliances

Watts vs kWh: What’s the difference?

The above table lists power consumption using two units: watts (W) and kilowatt hours (kWh). Here’s a quick rundown of what these terms mean. 

  • Watts are units used to measure power, just like metres measure distance. A kilowatt is equal to 1 000 watts just as a kilometre is 1 000 metres. 
  • Kilowatt hours are calculated by multiplying the power a device uses by the number of hours it’s in use. A 750 watt (0.75 kW) vacuum cleaner running for an hour will use 0.75 kWh of power while the same device running for 2 hours will use 1.5 kWh.

How to calculate your solar power needs

By doing an electrical audit on your household devices, their power usage per hour of use and the number of hours they are turned on every day, you can calculate your monthly energy requirements

Alternatively, you can estimate your usage based on your most recent Eskom bill. 

Let’s take a look at typical electricity requirements of three different households. 

  • Small household of 1 to 2 people. With a monthly Eskom bill of R1 012, this home consumes 422 kWh a month and could easily offset this usage with a basic solar power system or opt to use solar for TV and other small appliances to reduce their bill. 
  • Medium sized home with 3 to 4 inhabitants. This family spends R2 440 a month on electricity, consuming 1 017 kWh per month. A larger solar setup with multiple panels, a small battery and a high-quality inverter is recommended. This would allow the family to use solar for computers and other electronic devices as well as running their lighting during load shedding. The solar will also supplement their normal day-to-day usage even when there is no outages, effectively dropping their pull from the grid, and subsequently their Eskom bill.
  • Large home housing more than 6 people. This household consumes a substantial 2 083 kWh of power per month with an electricity bill of R5 000. A full solar array with an inverter and battery storage would be needed to effectively take this home off grid. This would allow the owner to use solar for plugs and all other major power consuming devices including the geyser and electric fence. 

Once you have an understanding of how much power your home consumes, we can help you gauge your solar requirements and you’ll be ready to choose a solar power system that suits your home or business.

Get your free quote today to start your transition to solar energy.

*Source: Mybroadband



No matter your electricity requirements. Switch and become a part of the renewable energy revolution. By switching to a suitable solar power system you help protect the environment and reduce your reliance on the South African electricity grid.


Whether it's new technologies and features, or updates on state-by-state policies and regulations, you'll find all kinds of exciting news here.

WhatsApp Icon