Solar load calculator

Find out what you need to power

Four quick steps. Choose your appliances, and your system size and indicative price update as you go. No sign-up needed until you want a quote.

1Your situation

This sets how much sun we can count on and how much backup you want.

We use typical sun hours for the region.
Winter sizing means fewer surprises in June and July.

2What do you want to run?

Set how many of each, and roughly how many hours a day they run. Defaults are typical, so only change what you know.

Something not listed?

Find watts on the appliance sticker or plug (W). If it only shows amps, multiply amps × 230.

3Get a quote

We will send your selections to approved providers in your area. They will contact you to confirm site details and give a firm price.

Estimates are indicative only. Final design and pricing depend on a site visit by a registered installer.

How this calculator works

Solar-Rescue's load calculator turns your appliance list into a system size in four steps. Every assumption is shown, so you can check the maths or discuss it with an installer.

1. Daily energy (kWh)

Each appliance's power in watts is multiplied by the hours it runs and the share of time it is actually drawing power (fridges cycle on and off). The total is your daily energy use.

2. Panels

Daily energy is divided by your region's sun hours and a 75% system efficiency to find the solar array size, then divided by a 550 W panel. Winter sizing is the safest choice for off-grid homes.

3. Inverter

The inverter is sized for your likely peak load, including the start-up surge of motors such as pumps, fridges and air conditioners.

4. Battery

Battery size is your daily energy multiplied by how much backup you want, divided by the usable share of a lithium battery (90%).

Prices are indicative placeholders in rands excluding VAT, and savings assume a flat electricity tariff. A registered installer must confirm any design after a site visit. Want to understand the parts first? Read how a solar system works, our sizing guide or browse all articles.