This is a case study of a typical 3 bedroom house, with a family of 4.
While it provides indicative costing and provides an analysis of a typical situation, the costing can vary based on:
- Size of the house
- Multiple story houses impacts the cost of installation equipment and the complexity of the installation.
- Availability and strength of the sun in your area.
My Assumptions :
- The suggested energy solution for a stove that is used regularly by the family is to use a gas stove. This is not only cost effective, but due to the high current usage can be easily achieved by a gas stove, which is always available during load shedding. I have therefore excluded the gas stove from the calculation.
- For the geyser, I used a solar geyser, which is a separate installation. Smart Tech can quote separately for this. Also excluded from this calculation.
- For the pool, it is best to have a solar pool installation, which will be excluded from this calculation.
For these additional installations, Please chat to a Smart Tech sales representative.
Current Consumption Analysis
The 3 bedroom house will typically have these appliances and monthly power usage. (Note: Power usage is measured in kilowatt hours – kWh)
| Appliance | Load Description Notes | Monthly Usage (kWh) |
|---|---|---|
| Double Door Fridge | Largest contact Load | 90.00 |
| Laptops | 3 devices | 58.50 |
| General / Standby Loads | Including WiFi / Routers | 40.50 |
| Kettle | High-power kitchen appliance | 31.50 |
| Airfryer | High-power kitchen appliance | 27.00 |
| Energy Saving Lights | 24.00 | |
| TV’s | 2 devices (The wife wants to watch soaps) | 21.60 |
| Microwave | 10.80 | |
| Cell Chargers | 4.80 | |
| Gate / Garage | 0.60 | |
| Total | 309.30 |
This energy profile indicates a significant base load that can be completely offset by a solar PV solution.
Current Monthly Usage : 309 kWh
Currently Monthly Grid Cost : R1,070
Proposed Solar PV Solution
The optimized solar system is designed to match and slightly exceed the baseline 309kWh consumption while providing essential back-up power.
The essential products for a solar system to suite this energy requirement is :
- Solar Array : 3.3 kWp (Six 550W Tier-1 panels) – Expected generation : Average 334kWh per month (covers 100% of base usage)
- Inverter : 5kW Hybrid Inverter (Capable of handling peak household loads)
- Battery : 5.12 kWh LiFePO4 Battery (Provides 5-8 hours of load shedding back-up)
Investment and Financial Return
Total investment breakdown.
The all-inclusive installed price is R83,000 covering all components, labour and compliance. (Smart Tech only recommends qualified installers)
Savings and Payback
The system provides a clear financial return by eliminating most of your current grid dependency.
Old Monthly Bill : R 1,070
New Estimated Monthly Fixed Charges : R 250
Total Monthly Savings : R 820
Total Annual Savings : R9,840
Calculated Payback Period : 6.2 Years
In Summary : The R 83,000 investment is recovered at the approximately 6.2 year mark. Thereafter the system generates pure savings, protecting your household from future electricity price increases. From purely an investment stand-point, this is very good investment.
Hidden benefits
To also note that not included in the calculation above are :
- The Lifespan Factor: Most Tier 1 panels have a 25-year warranty. This means after year 8, they get 16+ years of “free” electricity.
- Electricity Hikes: As Eskom/municipal rates rise, that 8.4-year payback actually shrinks because the “savings” grow more valuable every year. If you consider that the average electricity price hike over the last 5 years has been in excess of 12%.
- Recalculating the payback period reduces this period to under 6.2 years.
- By factoring in the price hikes, your monthly savings grow every year, accelerating the “break-even” point:
- Year 1: Saving R820/month (Total: R9,840)
- Year 2: Saving R918/month (Total: R11,021)
- Year 3: Saving R1,028/month (Total: R12,343)
- Year 4: Saving R1,152/month (Total: R13,824)
- Year 5: Saving R1,290/month (Total: R15,483)
- Year 6: Saving R1,445/month (Total: R17,341)
- Month 74: You cross the R83,000 mark.
The Power of Compounding: From R820 to R7,000+ per month
In year 20, The monthly savings in this instance would be R7,062. In year 20, with the solar system paid off, the electricity saving is pure profit.
- Property Value: Research shows solar installations can increase property value by 3% to 8%, often covering the initial cost immediately upon resale.
