One of the first questions people ask is: “How many panels do I actually need?” The answer depends on three main things: how much electricity you use, how much sun your roof gets, and how much of your bill you want solar to cover.
1. Typical electricity use in South African homes
Eskom, municipalities and Stats SA data all point to a wide spread of household usage bands. Here’s a practical translation of that data into monthly and daily usage, along with the system sizes they usually require.
| Home type | Monthly use (kWh) | Daily use (kWh) | Typical system |
|---|---|---|---|
| 1–2 bedroom flat / small home | 350–550 | 12–18 | ± 2–3 kWp |
| 3-bedroom family home | 650–900 | 22–30 | ± 4–5 kWp |
| Large 4–5 bedroom home | 900–1 400 | 30–45 | ± 6–8 kWp |
These are ballpark figures; electric geysers, pools and underfloor heating can push usage far higher.
2. How South Africa’s sun hours affect panel count
South Africa averages roughly 4.5–6.5 peak sun hours per day depending on region. A 1 kWp solar array therefore delivers around 4.5–6.5 kWh per day on average.
The calculator uses conservative peak sun hours per province so that your system is more likely to overperform. Examples include Gauteng (≈5.0 hours), Western Cape (≈4.8 hours) and the Northern Cape/Limpopo corridor (5.5–6.0+ hours).
3. The panel count formula (simplified)
Modern panels in South Africa are often around 550W (0.55 kWp). Once you know the system size you need, the panel count is straightforward:
Installers may specify slightly smaller or larger panels, but this formula keeps your expectations grounded when comparing quotes.
4. Real South African examples
Below we mirror what the SolarSaverZA calculator does and keep assumptions conservative – ideal for sanity-checking installer recommendations.
Example A: Small home (2–3 people)
- Monthly usage: 450 kWh
- Daily usage: ±15 kWh
- Province: Gauteng (≈ 5 peak sun hours)
- Coverage target: 80%
Example B: 3-bedroom family home
- Monthly usage: 750 kWh
- Daily usage: ±25 kWh
- Province: Western Cape (≈ 4.8 sun hours)
- Coverage target: 80%
Example C: Large home with pool and heavy appliances
- Monthly usage: 1 200 kWh
- Daily usage: ±40 kWh
- Province: KZN (≈ 5.5 sun hours)
- Coverage target: 100%
5. Where do batteries fit in?
Panels generate energy; batteries store it for nights and load-shedding. Battery sizing is usually discussed in kWh, with a handy rule of thumb:
- 5 kWh battery – runs essentials for a few hours
- 10 kWh battery – covers a typical suburban home through most stages of load-shedding
- 15 kWh+ – for large homes or when heavy loads must stay on
Batteries don’t change panel count directly, but they influence inverter choice and final system cost, so build them into your comparisons. Many South African cost guides (for example LocalPros’ 2025 PV price overview ) group systems into packages that combine panels, inverters and batteries at different sizes for this reason.
6. How this aligns with the SolarSaverZA calculator
The SolarSaverZA calculator automates these steps with local assumptions:
- Monthly bill → estimated monthly kWh using current Eskom/NERSA tariffs
- Province → realistic peak sun hours based on SA resource data
- Coverage target → system size in kWp, panel count and cost range
- Simple savings and payback estimate for quote comparisons
References & data sources
- Department of Mineral Resources and Energy – Solar power overview: dmre.gov.za/…/solar-power
- Minister of Mineral Resources and Energy – Solar Power Africa 2022 address (solar irradiation and sunshine hours): gov.za/news/speeches/…
- Eskom – Tariffs and Charges (context for typical usage bands): eskom.co.za/distribution/tariffs-and-charges
- PowerOptimal – “Eskom tariff increases vs inflation since 1988” (electricity price context): poweroptimal.com/2024-update-eskom-tariff-increases-…
- LocalPros – “How much do solar panels cost?” (system cost examples): localpros.co.za/cost/how-much-do-solar-panels-cost