Solar and backup power: what adds value

Why buyers ask about it

Backup power has become one of the first things South African buyers ask about. A good system keeps the lights, Wi-Fi, fridge and alarm running during an outage, and solar panels can lower the electricity bill. But not every system adds the same value, and a poorly installed one can be a liability. Here is how to tell the difference.

The parts of a system

• Inverter: the heart of the system. It turns battery or solar power into the 230 V power your plugs use and switches over when the grid goes down. Its size (in kW) limits how much you can run at once. A hybrid inverter can take power from panels, batteries and the grid.
• Battery: stores energy for when there is no power. Its usable capacity (in kWh) decides how long you can run things. Lithium iron phosphate (LiFePO4) batteries are now common; they last longer and can be discharged more deeply than older lead-acid batteries.
• Solar panels: generate power during the day, charging the battery and running the house. Their total size is given in kWp.
• A generator, if there is one: useful for long outages, but noisy, and fuel costs money.

What adds the most value

A system that was designed for the house, installed by a qualified installer, and documented properly. A buyer, and a bank valuer, can only give credit for what can be shown to work and to be safe. A big system with no paperwork may be worth less than a modest one with a complete file.

Owned outright is simpler than rented. Some systems are rented or financed through a contract; if so, find out whether the contract transfers to the buyer, what the monthly cost is, and what happens if you decline it.

The paperwork to ask for

• An electrical certificate of compliance (CoC) that covers the solar and backup installation, issued by a registered electrician. A general CoC for the house that predates the installation does not cover it.
• Proof of registration with the municipality (or Eskom, where it supplies the area) if the system is connected to the grid. Many municipalities require grid-tied systems to be registered and approved; an unregistered one can lead to penalties or a demand to disconnect.
• The installer’s details, the installation date, and the warranties for the inverter, batteries and panels, and whether they transfer to a new owner.
• A short description of what is on backup: which plugs, lights and appliances run during an outage. “Essential loads” varies a lot from house to house.

Questions to ask the seller

• How old are the batteries, and how long does the system last through a typical evening outage?
• Has the system ever been serviced or had a fault? Who did the work?
• What has the electricity bill been since it was installed?
• Is the system included in the sale price, and is it listed in the offer to purchase as a fixture?

“Solar ready” and other phrases

A “solar ready” house usually has some wiring or a changeover switch prepared, not panels. “Inverter” on its own may mean a small unit with a battery for a few lights. Read the listing carefully and ask what exactly is installed.

If a home you like has no backup, the cost of adding a system can sometimes be financed through your bond or a further loan; the bond calculator shows what a larger bond would cost each month. This is general information, not technical or financial advice; have an accredited installer inspect a system before you rely on it.