How much money have you actually saved installing solar ?

**Tradie** · 01-Apr-25, 08:09 AM

If you installed a solar system in 2023, I would be interested to see how your ROI is going.

It would be interesting to compare a 5 kw (R100- 150 K to an 8 kw R150 - R250K if installed in 2023)

I did a few calculations using actual data collected from installed units, and the results are rather interesting.

Looking at it realistically (a system with 12 panels) , I would say if all goes well and the price of electricity keeps going at the current rate, and no additional fees are added to the bill, it might just even out the cost in about 12 - 15 years.

Looking at it from a convenience point of view, the value of the system has already paid for itself 10 fold.

However when we look at the amount of grid failures and the duration of these grid failures, the load shedding system is currently just not suitable. Looks like we are going to be be going back to adding generators to keep lights on, or laying out thousands on batteries, which are great if we have sunny days.

**GCE** · 01-Apr-25, 12:10 PM

Not sure how you getting to 12 to 15 years
I have looked at various systems that we have installed and depending on Qty of batteries come in at between 5 and 8 years

Standard 5kw system with 5kwh battery we are seeing 22K a year savings .If I take the 22k and add 10% for increases every year it is 4 years and 100K is saved . We seeing 3K bills come down to R700 and likewise bills that are up at 4K mark down to R700 .
Where bigger battery systems have been installed we see R0 bills coming in but the pay back period inc due to the cost of batteries

**Tradie** · 01-Apr-25, 12:50 PM

Originally Posted by GCE

Not sure how you getting to 12 to 15 years

It's the figure people are using, 10 year warranty for an inverter/battery combo, one of the reasons we only install combo unit with a 10 year warranty. Our oldest unit is only 3 years old, are they going to last 10-15 years, only time will tell.

The last of the older Axpert units that we installed, have been replaced, Many of them have had PCB issues, you hear a bang and puff of smoke and you in for a board replacement, we dont bother anymore, just replace. We only have a few FLA batteries in trolley type inverters, which will be replaced with a drop in lithium battery.

Dont you install Victron units, which batteries do you install?

**Tradie** · 01-Apr-25, 12:53 PM

How do you figure out the ROI and savings?

Originally Posted by GCE

Standard 5kw system with 5kwh battery we are seeing 22K a year savings .If I take the 22k and add 10% for increases every year it is 4 years and 100K is saved . We seeing 3K bills come down to R700 and likewise bills that are up at 4K mark down to R700 .
Where bigger battery systems have been installed we see R0 bills coming in but the pay back period inc due to the cost of batteries

**Tradie** · 01-Apr-25, 01:28 PM

Let do a quick calculation for 2023, using some data collected, no feedback. I am not aware of any customers who have had the correct meter installed, only a notice to inform the customer that it is illegal to feedback electricity into the grid.

Solar cost to purchase and install (with a COC) 8 kw system with 2 batteries and 12 x 545 watt panels - R210 000 (average cost in 2023)

PV - 1997.3
Load - 3884.9
Export - 2.6
Import - 5923.3
Discharge - 1110
Charge - 1310

Using the scale 4 as for the example, without complicating the calculation we will just use the 2023-2024 tariff R2.97 (it will make the roi look better)

If we divide the total by 12 to get an average monthly bill - 5923.3 kwh/12 = 493.61kwh

The average bill should be around R1466.02 per month.

The savings would be the PV generated ?

1997.3/12 = 166.44 kwh per month

166.44*2.97 = R494.33 per month.

How much ROI for the solar installation and savings on the bill, less the council registration, PR engineer, TOU tarrif and monthly council fee?

**Tradie** · 01-Apr-25, 01:53 PM

What sort of budget do we need to consider when installing solar?

Initial outlay for a system -

1 x 8 kw inverter R28 000
2 x 10 kwh batteries R35 000
18 x 550 watt panel R28800

Total excluding all the its and pieces = R91800.00

Plus bits and pieces = R120 000 ( a rough estimate)

Council registration, including COC and PR engineer and new meter installation = ?

Tariff upgrade to TOU = ?

Monthly additional cost added to your monthly council account = ?

Feedback tariff = ?

Am I missing anything ?

**GCE** · 01-Apr-25, 03:07 PM

We see the average house hold above 500 units a month , generally around 700 units
PE , we have 3 prepaid meter tariffs , first 250 units ( R 3.08/kwh) , 2nd 250 units ( R3.66/kwh) and the the rest ( R 4.05/kwh) so anybody over 500 units starts saving quickly .

We don't need engineer sign off and the 4 quadrant meter comes in at +/-R7K

Monthly charge on a 4 quardrant TOU with feedback is Monthly charge R104.34 +vat SSEG support charge R 52.17 + vat = Total inc Vat R 179.99

I was on prepaid ( with solar fitted) and cost was around R700 per month , just had meter fitted and now down at R 300 per month inc TOU and monthly charges

Savings on first year was R 22 304.40 while on solar meter - Reckon if I had TOU I would have had savings of R29K

Had a client make a statement over a beer that there is no way he will ever break even on his system - 5KW panels , 8Kw Deye 15Kwh Weco 5k3 batteries - Did a quick calc and got a savings of R 27K year 1
He would be looking at 7 years with 10% per year increase - Last year in PE we effectively had 16% inc on first 500 units and then 12,5% on the balance
Also just had TOU meter fitted - He has dropped his Bill further as the majority of import is at night on off peak at R1,66/kwh vs the lowest prepaid tariff at R 3/kwh

**GCE** · 01-Apr-25, 03:11 PM

Originally Posted by Tradie

How do you figure out the ROI and savings?

Take the units consumed for the month - Work out what it would have cost in prepaid without solar - minus what it costs with solar = savings

Have attached a sheet that I used to do a quick calc

**Tradie** · 02-Apr-25, 06:58 AM

This is a prepaid installation, with solar installed, using 2024 per kwh rate (R2.976)

PV - 1997.3
Load - 3884.9
Export - 2.6
Import - 5923.3
Discharge - 1110
Charge - 1310

Monthly average bill is 5923.3/12= 493.58kwh per month

493.58 kwh per month x R2.97 = R1465.93 loaded into the meter per month.

Solar generated average per month 1997.3/12 = 166 kwh (used)

166 x 2.97 = R493.02

R493.o2 x 12 = R5916.24 saving per year.

Cost to install R220 000/R5916.24 = 37 years to pay back the initial cost at this rate, this excludes registration costs, monthly utility fees, PR engineer and all the other little costs, like maintenance panel cleaning, maintenance inspections, etc,etc.

It would be great if we could get meters to feedback and optimise the system.

The customer has requested more solar panels, however the data collected shows its not a solar panel issue, there is plenty power not being utilised during the day, it's a storage issue (TOU), adding more batteries to utilise the power during peak hours (6-9 pm and 4-7 am) , when the most power is used, would be the best way to reduce the bill. The system idles from 9 am once the batteries are fully charged.

**Derlyn** · 02-Apr-25, 07:32 AM

At the end of the day, installing solar is more about convenience than saving money.

If one uses the money that would have been used to install solar on money making ventures, a lot more can be made than the savings that having solar will offer one.

If one takes the money saved on the electricity bill seen as a percentage of the cost of installing the system, it is clear that installing solar is a dumb idea if saving money is the sole motivation of the project. That money can be put to better use.

As I said, it's all about convenience and it is my opinion that this ROI talk is only sales talk.