Three quotes, three different sizes, three very different prices. Here is how to compare solar proposals on substance instead of on the bottom line.
Collect three solar quotes in South Africa and you will usually receive three different system sizes, three different brand mixes and prices that vary by half. They cannot all be right for your property. The way through is to compare the engineering behind the numbers, not the numbers alone.
First: are the systems even comparable?
Before judging price, normalise what is being offered. Write down each quote's PV capacity in kWp, inverter capacity in kW, usable battery capacity in kWh, and what is included beyond hardware: design, certification, registration, monitoring, workmanship warranty. A cheaper quote is often simply a smaller or emptier one.
- kWp of panels, and the panel brand and wattage
- Inverter brand, capacity and whether it is hybrid-capable
- Usable battery kWh (not nominal), chemistry and cycle warranty
- Mounting specification and roof penetrations
- Certificate of Compliance, SSEG registration and commissioning documentation
- Workmanship warranty, and who backs the equipment warranties locally
Interrogate the sizing logic
The strongest signal of quality is whether the proposal references your actual consumption. A credible quote states the load profile or bill data it was based on and shows expected generation against your usage. If the system was sized without asking how you use electricity, it was sized for the installer's margin, not for your property.
Check the compliance chain
Every legitimate installation ends with a Certificate of Compliance signed by a registered person, and grid-connected systems must be registered under SSEG rules. Confirm who does this work and that it is priced in. An unregistered system can surface later as an insurance repudiation or a blocked property transfer, which erases any saving from a cheaper quote.
Weigh the warranties properly
Panels typically carry long performance warranties, but inverters and batteries do the hard work and fail first. Look at the inverter warranty term, the battery cycle or throughput warranty, and crucially whether the brands have real South African support. A warranty honoured through a local office is worth more than a longer one backed by an importer that may not exist in five years.
Then, and only then, compare price
With scope normalised, sizing justified, compliance included and warranties understood, price becomes meaningful. Divide capital cost by modelled annual kWh offset to compare quotes on cost per kWh delivered, which is the number that actually matters over the system's life. Our ROI calculator shows the modelling approach we use, and an energy assessment will give you a proposal built to be interrogated exactly this way.