Load shedding stopped being the story. Your bill just became one.

On 1 July, City Power's new tariffs came into effect. NERSA approved an average increase of 8.63%, and in rands and cents that means a typical household using 250kWh a month now pays R680.93, up from R624.65. A family home on 450kWh a month goes from R1,438.21 to R1,559.79. That's real money, every month, indefinitely.

Two days earlier, Eskom put out a very different number. As of 3 July, the country had gone 413 consecutive days without load shedding. For over a year, the thing every homeowner in Johannesburg used to plan their evening around simply hasn't happened.

Put those two facts next to each other and you get the actual story: the supply crisis eased, and the bill went up anyway. City Power's own bulk electricity costs from Eskom rose 9.01%, on the back of a R54.7 billion correction NERSA made to Eskom's regulatory asset base. None of that has anything to do with whether your lights stay on. It has everything to do with what you pay for the power you use.

The story the industry told wasn't wrong. It's just no longer the whole story

For years, mine included, the smart home pitch in South Africa leaned hard on resilience: batteries, local control, systems that don't care if the grid drops. That's still true and still worth having. But it answered a question homeowners are asking less often now. The question that matters this winter is simpler: what does this room actually cost me every month, and can I change that?

Why the block structure matters more than the headline percentage

City Power's residential tariffs aren't flat. They're stepped. You pay one rate for the first band of usage, a higher rate once you cross a threshold, and a higher rate again above that. The 8.63% average increase isn't what any one household actually pays, it's an average across customer categories, some of which saw smaller increases (5.91% for Domestic Single Phase customers) and some larger (8.71% for Residential Prepaid High).

What that means practically: a single large load run at the wrong time doesn't just cost what it costs, it can tip your whole month into the next pricing band. A geyser is commonly cited by South African energy analysts as 30 to 50% of a typical household's electricity bill, by far the single biggest controllable load in most homes. Run it on a dumb thermostat that reheats a full tank overnight regardless of who's home, and you're paying top-tier rates for hot water nobody used.

What actually changes with automation

This is where KNX earns its place, and it's a different argument to the one I've made about load shedding. A KNX system doesn't just switch the geyser on a timer. It ties geyser and pool pump scheduling to real household patterns, keeps HVAC off in rooms nobody's in, and where there's solar and battery on site, prioritises self-consumption over grid draw specifically when grid power costs the most. For properties on time-of-use tariffs, larger homes and commercial connections mostly, that timing difference between peak and off-peak isn't trivial.

None of this depends on the grid being unreliable. It works exactly the same whether Eskom is having a good year or a bad one, because the target isn't outages anymore. It's the meter.

What to spec before the walls close

I build this on Hager and Ekinex switching actuators for the geyser and pool pump circuits, with monitoring at the DB level so a client can actually see where the money's going, not just guess. If the inverter on site talks Modbus or a similar open protocol, which most decent solar setups do these days regardless of brand, that ties in too, so the system knows whether it's drawing from solar, battery or grid at any given moment, not just whether the sun's up. 1Home bridges all of it into Home Assistant and Apple Home if a client wants the dashboard on their phone.

None of it is complicated to spec. It's a conversation at design stage about which circuits get a relay and which don't, before the ceiling's closed and that decision gets a lot more expensive.

The question worth asking now

For a few years the question was "what happens when the power goes out." That's mostly answered. The question worth asking your installer now is "what is this room actually costing me every month, and does anything in this house know that." If the honest answer is "nothing, it just runs," that's worth fixing before the next tariff letter arrives.

If you're planning a build or renovation and want a system that actually manages what you pay, not just whether the lights stay on, get in touch. Just a conversation about what the project needs.

Wayne | KNX Logic

wayne@knxlogic.co.za | 082 564 3982 | www.knxlogic.co.za