Get an itemised quote you can compare
Insist on a line-by-line quote, not a single lump sum. It should list each component separately — panels, inverter, battery, mounting, cabling, protection and labour — with VAT shown clearly so you know whether the figure is inclusive or exclusive. Ask for the spec sheets (datasheets) of the actual inverter, battery and panels being installed, by make and model. That is the only way to compare two quotes fairly: a cheaper price often means a smaller battery, fewer panels or a lower-spec inverter, and the spec sheets are where those differences hide.
Battery depth of discharge (usable vs rated kWh)
A battery's rated size is not the same as what you can actually use. Depth of discharge (DoD) is the share you're allowed to draw before the battery management system stops you, and it protects the cells from damage. A 5kWh battery rated at 80% DoD gives you 4kWh usable; at 90% or more you get closer to 4.5kWh from the same rating. During load-shedding those extra usable kilowatt-hours are exactly what keep your lights, fridge and Wi-Fi running, so compare usable kWh — not just the headline number on the box.
Battery cycle life and lifespan
A cycle is one full charge and discharge. Good lithium (LiFePO4) batteries are rated for several thousand cycles — often around 6,000 — before they drop to a set share of their original capacity. If you cycle a battery roughly once a day, 6,000 cycles points to well over a decade of daily use. Lower-cycle batteries are cheaper up front but may need replacing sooner, so a battery's real cost is its price divided by the usable energy it will deliver across its whole life, not just the sticker price today.
Battery and brand quality, warranties, reputation
Not all batteries carrying the same rating are built to the same standard. Look at the brand's track record, whether it has local support and stock in South Africa, and read the warranty properly — how many years, how many cycles, and what retained capacity it guarantees at the end of the term. A warranty is only as good as the company standing behind it, so check it is backed here at home, not just by a distant overseas factory. Ask who honours it if something fails in year four.
Inverter sizing for your loads and solar
The inverter is the heart of the system: it sets how much power (in kW) you can run at once and how many panels it can accept. Undersize it and it will trip when the geyser, kettle and oven come on together; oversize it and you pay for capacity you never use. Sizing should start from your actual peak load and your daily consumption, not a guess. Make sure the inverter can grow with you too — if you plan to add panels or a second battery later, it needs the headroom to take them.
Inverter monitoring features
A good inverter comes with an app or web portal that shows, in real time, what your panels are generating, what your home is drawing, how full the battery is and how much you're still pulling from the grid. That visibility is genuinely useful: it helps you shift heavy loads to sunny hours, spot a fault early, and actually see the savings you were promised. Ask whether monitoring is included and free, whether you (not just the installer) get access, and whether it works remotely from your phone.
NRS approval and SSEG registration
If your system feeds back to the grid, the equipment must be NRS 097-2-1 approved and the installation signed off by a qualified installer, with a Certificate of Compliance. On top of that, most municipalities require you to register a grid-tied system as Small-Scale Embedded Generation (SSEG) — even if you never export a single unit. Skipping registration can mean penalties, problems at resale, or issues with your insurer. A reputable installer will use NRS-approved equipment and guide you through the SSEG application for your municipality.
Payment terms: ownership, escalation, buy-out
Read the finance structure as carefully as the tech. If you're renting or subscribing rather than buying outright, ask three questions: who owns the system and when does it become yours; does the monthly payment escalate each year, and by how much; and what is the buy-out or settlement figure if you want to own it early or move house. A low monthly figure can hide a steep annual escalation or a large buy-out. Get every number in writing so you can compare the true lifetime cost, not just month one.
Roof suitability, orientation and shading
Your roof decides how much sun your panels actually capture. In South Africa, north-facing surfaces generate the most over the year, while east and west split production across morning and afternoon. Shading from trees, chimneys, a water tank or a neighbour's wall can drag down a whole string of panels, so it needs to be assessed properly. Have the roof's age, material and condition checked before install too — you don't want to lift panels in two years to fix leaks or replace sheeting underneath them.
