Rewiring South Africa

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

Households
Start with the geyser. It is 40–50 % of your bill.

Your smartest next step

ranked by payback

Solar is rarely the first rand you should spend. In a South African home the electric geyser is 40–50 % of the electricity bill, and the cheapest fixes pay for themselves in months. Tell us what you already have and we will rank what is left.

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.

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, defrost scheduling, then heat recovery from the condensers
  • 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
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.