Energy Saving Guide · Home audit
Where does your electricity actually go?
You know what you paid. You probably don't know what you paid for. Was it the geyser, the pool, the heater in the bedroom, or the fridge in the garage?
You can map your home's electricity yourself in about a week, with your meter, a notebook and one formula: kilowatts × hours = kWh. Start with the big, long-running loads, because a few appliances usually explain most of the bill. Measure before you replace anything.
Kilowatts × hours = kWh. That one line explains most electricity bills.
Step 1: Get your baseline
Read the meter at the same time every day for seven days.
Daily use = today's reading − yesterday's. Multiply the average by 30 for a monthly figure, and compare it with your account or token history. If you're above 400 units a month in Tshwane, every extra unit costs about R4.75, and above 650 about R5.12 (2026/27, incl. VAT).
Step 2: Find the overnight floor
Read the meter last thing at night and first thing in the morning.
What's running overnight is mostly the fridge, freezer, geyser and standby devices. A surprisingly high overnight number is your best clue. Repeat one night with the geyser switched off at its isolator to see its share (see “Is your geyser quietly draining your budget?”).
Step 3: List the big loads
Wattage is on the label. Hours are up to you.
Write down each appliance's rated power (on the rating plate or in the manual) and how many hours a day it really runs. The usual heavy hitters:
- Geyser. Eskom says it can be up to 30–50% of a household's electricity. (see “Is your geyser quietly draining your budget?”)
- Space heaters and underfloor heating in winter. (see “Winter electricity shock: what your heater is really costing you”)
- Pool pump, which runs for hours every day. (see “The hidden cost of your pool pump”)
- Fridges and freezers, which run 24 hours a day. (see “Your fridge never switches off”)
- Tumble dryer and hot washes. (see “Laundry habits that quietly raise your bill”)
- Lights, especially halogen downlights left on for hours. (see “Are your lights adding more than you realise?”)
- Standby, which is small per device but always on. (see “The standby myth: what's really draining power while you sleep?”)
A few big, long-running loads usually explain most of the bill. Start there.
Step 4: Test one suspect at a time
Change one thing, then read the meter. Two changes at once tell you nothing.
Switch off one suspect for a day or a night and compare with your baseline. A plug-in energy meter (sold at hardware stores) measures single plug-in appliances directly. Don't leave the fridge or freezer off long enough to spoil food.
Interesting things about your bill
- Eskom has said the geyser makes up anywhere from 30% to 50% of a home's power, depending on the factsheet and the year. That range is exactly why you should measure your own.
- Peak hours are 5 to 9 p.m. Eskom asks households to shift loads like geysers and pool pumps out of that window to ease the grid.
- Tshwane's domestic tariff has no fixed monthly charge, so every unit you cut comes straight off the bill.
How to turn an appliance into rand
kWh = power in kW × hours. A 2 000 W (2 kW) heater for 3 hours = 6 kWh.
Month = daily kWh × 30. 6 kWh × 30 = 180 kWh.
Which rate. A saving comes off your top block. Most Tshwane homes using more than 400 units a month pay R4.75 a unit (401–650) or R5.12 (above 650), including VAT, in 2026/27. So we show savings as a range between those two rates.
Example. 180 kWh × R4.75 = R855; × R5.12 = R922 a month.
Watch out. Thermostats (geyser, fridge, heater with thermostat) cycle on and off, so rated power × hours overstates their use. Measure those instead.
Safety: don't open your distribution board, plugs or appliance wiring yourself. Electrical work must be done by a registered electrician, who issues a Certificate of Compliance (CoC) for fixed wiring.
Want a second pair of eyes? Lesedi Energy can help you read your meter data and check the electrical side of your home safely. We measure first and recommend only what's needed. Use the contact button on this page to get in touch.
Lesedi Energy: Smarter energy decisions start at home.
Sources (checked 16 Oct 2026)
- Geyser up to 30% of monthly energy; peak 5–9 p.m.: Eskom factsheet 'Use only the electricity that you need': https://www.eskom.co.za/eas/wp-content/uploads/2021/04/RES-FACT-SHEET-USE-ONLY-Final.pdf (opens in a new tab)
- Geyser up to 50%: Eskom, 'Energy-wise ways to get ready for winter': https://www.eskom.co.za/energy-wise-ways-to-get-ready-for-winte/ (opens in a new tab)
- No domestic fixed charge: NERSA Gauteng approved tariffs 2025/26: https://www.nersa.org.za/files/files/2025/09/GautengApprovedtariffs2025_.pdf (opens in a new tab)
- Tshwane 2026/27 block rates (R4.75 for 401–650 units, R5.12 above 650, incl. VAT; City figures, gazette check pending): City of Tshwane: https://www.tshwane.gov.za/?p=102188 (opens in a new tab)
- All rand figures: calculated (method box above).