Why is my electricity bill still high after installing solar?

If your bill dropped less than the installer promised, the system is not necessarily broken. Work through the causes below in order. Most of them cost nothing to fix, and the first one is not fixable at all, so it is worth knowing how big it is.

1. Fixed charges do not shrink when you go solar

Every South African distributor recovers part of its network cost through a fixed monthly amount. Solar reduces the kWh you buy; it does not touch that line. These are the 2026/27 figures from the distributors’ own schedules:

Eskom also moved more of its Homepower and Homeflex cost into these fixed lines this year and lowered energy rates to compensate. That is why some Eskom-direct homes saw the bill fall less than expected even with the same panels. A home that used to pay R2 500 a month in Cape Town will not get to R0; the floor is the fixed charge.

2. Your battery may be charging from the grid

Most hybrid inverters have a setting that lets the battery charge from Eskom or the municipality on a timer. Installers often switched it on during the load-shedding years so the battery was full before the next outage. If that is still active, you are buying grid kWh every night or every morning, sometimes at a peak rate, and storing them with a small efficiency loss.

Check: open your inverter app, find the system-mode or time-of-use page, and look for a “grid charge” tick box against each time slot. Leave it on only if you are on a time-of-use tariff and deliberately charging in the cheapest period, or if you want a full battery before forecast bad weather.

3. You are exporting what you could be using

An exported kWh earns far less than a kWh you avoid buying. On 2026/27 rates a Cape Town Home User avoids 355.95c to 469.06c for each kWh used at home but is credited about 152.93c for each one exported (both incl. VAT, including the SSEG incentive). On Homeflex in summer a standard-hour kWh you use yourself avoids roughly 307.51c once the per-kWh network charges are included, against an export credit of 218.35c. Our Homeflex export answer shows the full table.

Check: look at the daily graph in your app. If it shows a big export hump at midday and grid import after 17:00, move flexible loads into the day: geyser timer to 10:00–15:00, pool pump during sunshine hours, dishwasher and washing machine on delay start, and EV charging in daylight if you have one.

4. The expensive loads still run after dark

Solar produces nothing at night, so a geyser that reheats at 18:00, a tumble dryer, or an air conditioner in the evening all come straight from the grid or drain the battery. The geyser is the big one in most SA homes. A timer, a smart relay or a heat pump usually does more for the bill than another row of panels. See water heating for the options.

5. Settings or wiring problems

• The grid current sensor is in the wrong place or the wrong way round. Hybrid inverters use a clamp (a CT) on the incoming supply to measure what the house draws. If it is reversed or fitted after the wrong breaker, the inverter can misjudge the load and import when it should be using solar. A sudden jump in grid use after an electrician did other work is a clue.
• Battery reserve set too high. If the battery never discharges below 60% because the backup reserve is set there, most of its capacity is never used for savings. With load shedding largely gone, many homes can lower the reserve and use the battery every evening.
• The inverter’s own consumption. Every inverter draws power to run, day and night. Check the “no-load” or “self-consumption” line on its datasheet and confirm the installer chose a model sized for your house, not the biggest on the shelf.

6. Winter, dirt and shade

Output is lower in June and July than in summer, shadows are longer, and Highveld dust builds up quickly in the dry months. Compare this month with the installer’s monthly yield estimate rather than with your best summer month. If production is well below the estimate on clear days, ask for a check before blaming the tariff. Our panel cleaning answer covers safe cleaning.

7. The quote over-promised

Some sales proposals assume you will use every kWh the panels make, or that tariffs will rise by double digits every year. If the payback page in your quote has no self-consumption figure and no tariff code, its savings figure was a guess. Run your real numbers through our payback method, or send the quote through check a quote.

A quick 10-minute bill audit

1. Split last month’s bill into fixed charges and energy (kWh) charges. Only the energy part can fall.
2. Compare grid kWh this month with the same month before solar.
3. Open the inverter app and note daily production, export and grid import.
4. Switch off grid charging unless you chose it deliberately.
5. Move the geyser and pool pump into sunshine hours.
6. Lower the battery reserve if you no longer need a big backup buffer.

Related: 2026 electricity tariffs · is there a solar tax? · do I need a battery?

Quick questions

Will solar ever bring my bill to zero?

Not while you stay connected to the grid. The fixed monthly charges remain, for example R424.30 on Cape Town Home User and about R690 on Eskom Homeflex 1 in 2026/27.

Should I turn off grid charging on my inverter?

In most homes, yes. Leave it on only if you are on a time-of-use tariff and charge in the cheapest period, or you want a full battery ahead of bad weather.

Is exporting solar a bad idea?

No, it is better than wasting the energy, but each exported kWh earns roughly a third to two-thirds of what a self-used kWh saves, so use it at home first.

Sources

• City of Cape Town: The cost of electricity (Home User 2026/27)
• City of Cape Town 2026/27 Budget Annexure 6: consumption and generation tariffs
• Eskom Tariffs and Charges Booklet 2026/2027 (Homeflex and Gen-offset Homeflex tables)
• Eskom Distribution: 2026/2027 tariff increase and structural changes
• NERSA RfD: City of Tshwane 2026/27 (SSEG tariffs)
• NERSA decision: eThekwini 2026/27 tariff application