Rewiring South Africa

Independent advice on cutting energy bills through efficiency and electrification – for homes, businesses and industry.

Households

Your smartest next step

ranked by payback

To maximise savings, start with energy efficiency before installing solar. In typical South African homes, electric geysers make up 40–50 % of electricity bills. The cheapest options for reducing power costs pay for themselves in months. Tell us what you already have and we’ll rank what’s left.

Can electricity consumption be reduced before installing new power generating equipment?

Where the money actually goes

typical SA household
LoadShare of the bill
Electric geyser40–50 %
Space heating (June–August)~16 %
Fridges and freezers10–15 %
Lighting and standby10–15 %
Cooking8–12 %
Pool pump, where present10–20 %

Sources: SEAD/McNeil water-heater technical study for South African minimum standards, which puts the geyser at 40–50 % of household consumption; an Eskom survey of middle-income households put water heating at 39 % and space heating second at 16 %. Your own split depends on household size, whether you have a pool, and how much you heat in winter.

Renting?

you have fewer options – but not none

You cannot install a heat pump in a house you do not own, and roughly a third of urban South African households rent. What you can still do:

  • Turn the thermostat down to 55–60 °C. Free, reversible, and yours to do.
  • Buy LED bulbs and take them with you when you move. They are portable.
  • A plug-in geyser timer costs under R1,000 and comes off the wall on moving day.
  • Ask your landlord. A geyser blanket costs them R1,200 and cuts your bill – the split incentive is the whole problem, and it is worth naming in the conversation.

The structural fix is minimum energy performance standards for rental stock, so that a tenant is not paying to heat a roof space. That is advocacy, not a purchase, and it is part of what this organisation exists to push for.

Ready for solar?

size it against your own roof

Once you’ve reduced the amount of electricity you use and become an energy-efficient household, consider a solar installation. To size the system properly: trace your actual roof from satellite imagery, get the real solar resource for that spot, and see payback times against your actual bill.

Size your rooftop solar →
Opens the rooftop tool on GridTwin ZA in a new tab.
Commercial
Offices, retail, cold chain, hospitality

What this will cover

in development

Where your building is losing money

ranked by payback

Commercial buildings waste energy differently from homes. The geyser is not the story – HVAC, refrigeration and running hours are.

Also planned:

  • HVAC scheduling and setpoints – the cheapest commercial saving there is, and almost always misconfigured
  • Refrigeration for the cold chain – door seals, night blinds and defrost scheduling, before anything is replaced
  • Heat recovery – refrigeration condensers and air compressors already make hot water and throw it away. Capturing it buys no new energy at all, which is why payback is usually the shortest on this list
  • Thermal storage – a hot or chilled water tank stores energy for a fraction of what a battery costs, and often bolts onto equipment you already have. Chill or heat at midday on your own solar, use it through the evening peak
  • Time-of-use tariff optimisation – most commercial customers are on a TOU tariff and almost none actively manage against it
  • Rooftop solar and wheeling – including whether an offsite PPA beats your own roof, which depends on your load shape more than your roof area
  • Backup that earns its keep – sizing storage for load shedding without paying for capacity that sits idle
Agriculture
Irrigation, cold chain, dairy, packhouses

What this will cover

in development

A farm is not a large house. The loads are seasonal, the biggest one can usually be moved to any hour you like, and a lot of the energy is not electricity at all – it is diesel. That changes which questions matter.

Can electricity consumption be reduced before installing new power generating equipment?

What we plan to cover:

  • Irrigation scheduling against Ruraflex – irrigation is the most shiftable large load in the economy. On a time-of-use tariff, moving pumping out of the evening peak costs nothing and saves immediately. This is almost always the first thing to do and almost never the first thing done
  • Pump efficiency before pump replacement – worn impellers, oversized pumps and throttled valves waste more than most farms expect. A variable speed drive on a correctly sized pump is a different proposition from one bolted to the wrong pump
  • The diesel rebate, honestly – the rebate makes diesel cheaper than its pump-price suggests, so the electrification case is weaker on paper here than in most countries. Any comparison that ignores it is selling you something
  • Solar for daytime pumping – irrigation and sunshine coincide better than almost any other load and generation pair. Whether you need storage depends on whether you can shift the pumping, not on whether you want a battery
  • Cold chain for export – citrus, table grapes and stone fruit carry more value per outage hour than anything in a shop. Door discipline, defrost scheduling and thermal mass come before backup capacity
  • Dairy heat recovery – the milk cooler and the water heater are usually running against each other. Recovering heat from the one to feed the other buys no new energy at all
  • Generators that earn their keep – most farms bought diesel capacity during load shedding and now run it rarely. What it is worth today, and whether solar and storage would have been cheaper, is worth knowing before the next replacement

Why the order matters here

the argument in short

On a farm the cheapest saving is usually a schedule, not a purchase. Irrigation can run at three in the morning; a shop cannot move its trading hours. That makes tariff management worth more here than almost anywhere else, and it costs nothing.

Only after that does the size of a solar system become a sensible question – because by then you know what load you are actually trying to cover, and when.

Industrial
The gas cliff is coming. Electrification is one of only three answers.

What this will cover

in development
The gas cliff is the decision in front of you

The Pande–Temane fields in Mozambique supply roughly 90 % of South Africa's gas through the Rompco pipeline, and about three quarters of the recoverable reserves are already gone. Sasol has extended the plateau more than once, but supply to third-party industrial customers ends – and cannot be replaced except by imported LNG. Over 300 industrial customers are affected, and the Industrial Gas Users' Association has called it an existential risk.

If you burn gas for process heat you have three options, and only three:

  1. Switch to coal. Cheapest per kilowatt-hour today. It raises your emissions by roughly 70 %, exposes you to the carbon border taxes below, and moves you onto a fuel your customers are increasingly unwilling to accept.
  2. Stay on gas via imported LNG. Sasol's chief executive has put the LNG price at three to five times the current regulated $3.00–3.50/GJ. That is the honest number to plan against.
  3. Electrify. A heat pump does not beat cheap domestic coal on running cost. It does beat LNG – comfortably, at every multiple in that range.

The comparison that matters is therefore not electricity against the gas price you pay today. It is electricity against the gas price you will pay after the cliff. Set the calculator below to an LNG price and see for yourself.

Three things make the case stronger than the running cost alone.

  • Carbon border taxes protect your exports. The EU's Carbon Border Adjustment Mechanism prices the embedded emissions of imported goods, and other markets are following. If your product carries coal-fired process heat, that cost lands at the border whether or not South Africa taxes it at home. Electrified heat on a decarbonising grid is the hedge.
  • Your customers have their own targets. Scope 3 commitments from multinational buyers increasingly reach into supplier emissions. Process heat is usually the largest single line in a manufacturer's footprint.
  • Electricity is the fuel with a floor, not a cliff. Gas supply is contracting and its price is about to be set by a global LNG market. Grid electricity has its own problems, but it is not about to stop arriving.

Process heat switching calculator

what your heat actually costs

Enter what you burn now and what temperature you need. This compares the cost of a useful kilowatt-hour of heat across the options, including carbon.

Also planned:

  • Heat pump feasibility screening – by sector, current fuel, process temperature and load factor. Food and beverage, textiles, pulp and paper, and chemicals have the most to gain.
  • Waste heat recovery – usually cheaper per kilowatt-hour saved than any new generation
  • Motors and variable-speed drives – the classic industrial win, still widely undone here
  • Compressed air – leakage of 20–30 % is common and almost nobody measures it
  • Solar thermal for process heat – South Africa's resource suits this unusually well
  • Carbon tax exposure – Phase 2 escalation changes the arithmetic on fuel switching, and the marginal abatement cost is computable rather than a matter of opinion
Why efficiency first
South Africa is not Australia, and the advice should not be either

The argument

Rewiring Australia's organising idea is “get off gas.” Australian homes burn gas for hot water, space heating and cooking, so household decarbonisation there is a fuel-switching story.

South Africa has almost no domestic gas. Homes here are already electric. They are electrified badly. So the argument is not fuel switching – it is:

Efficiency first, then generation.

The cheapest kilowatt-hour is the one you stop wasting, and in this country that kilowatt-hour is almost always hot water or process heat. That reframing matters for three reasons:

  • It is cheaper. A geyser blanket and timer together cost about R1,500 and pay back in months. Solar costs upward of R110,000. Nobody markets the blanket, because there is no margin in it.
  • It is about money. Tariffs have roughly doubled in five years. This is advice about a household or a firm's bill, and it should be argued that way rather than as a climate appeal.
  • It helps the grid most. The geyser drives South Africa's morning and evening peaks. Shrinking and shifting that load is worth more to the system than the same kilowatt-hours saved anywhere else.

The system-level modelling behind these claims is open and published at GridTwin ZA – the same hourly dispatch model of the South African power system, calibrated against Eskom's own weekly reports.

How we work

  • Every number is sourced or labelled an estimate. Where a figure is our own inference rather than a published one, we say so on the spot.
  • We are not a lead generator. No referral fees, no sponsored recommendations. The moment advice tilts toward whoever pays for it, it is worth nothing.
  • We will tell you not to buy something. Most households are quoted for solar when they should first be quoted for a geyser blanket.