Hello All

New to the forum, hope to learn great and wonderful things here and try my luck with one or more dumb questions.. I did try the forum search, but I did not get any results to my particular question..

I proposed the Solar for our house to the SO and when it came down to look at how we were going to finance it, she said no, let's finish other things in and around the house first.. No whole house solar for me, yet, sadly..

However, it is summer now and I am loathe to run my 1.1Kw pool pump every day for 8 hours, I die inside watching my units just vanish off the prepaid meter and can feel the my wallet burning a hole in my pocket..

To my dumb question then, could I get an off grid inverter and 3 - 4 solar panels to run my existing pool pump during the day, for free..? To my uneducated mind, I would need at least a 2KW inverter and 3-4 500 watt solar panels, assuming the inverter can kick in with that little panel..?

Thanks for your critique and input..

56 minutes ago, slayer said:

I proposed the Solar for our house to the SO and when it came down to look at how we were going to finance it, she said no, let's finish other things in and around the house first.. No whole house solar for me, yet, sadly..

It's a tougher sell now that we don't have load shedding, though note that Eskom continue to say that load shedding is "suspended". They are not saying that we are out of the woods yet, though clearly there has been an improvement.

Get good ball park figures for a system. Then build a plausible model of increases in the cost of electricity, and try to get an idea of ROI. Then it may seem a more sensible choice. Then again it may not. You are trading a big lump sum now for steady - and increasing - savings each month for the next 10 years. Do not calculate on the basis that solar will reduce your grid usage to zero. It won't. The sun doesn't shine all day every day (well... if you're up in the NW hoekie of the country you are getting close), so work on 90% reduction in useage. 

You don't say where in the world you are. In some areas (I'm in Johannesburg) you can cut your bill by switching tariffs. COJ famously introduced a fixed fee per pre-pay meter per month in the 2024/5 tariffs, but you can still save good money by switching to prepaid. Again, do the numbers first. There is usually a cost for conversion, and the per unit tariff will usually be higher on pre-paid, but the conversion cost is once off and your model will tell you if the savings will be worthwhile. I switched to prepaid before I got solar, and over the years it has saved me many thousands.

Another way to take a big chunk out of your bill is to change the way you heat water. Try to get an idea of what your geyser consumes per day and then do the sums. 

Or do all three! 

I was going to say that you need batteries or a grid connection to give a reference for your inverter, but I see companies offering completely off-grid solutions for pool pumps. These are advertised as needing no grid nor batteries. But you have to use their pump, you can't just change the way you feed power to your existing pump.

Anything that is just solar won't do much use if the sun doesn't shine. 

Batteries are usually the most expensive single component of a domestic PV system. If you were to just get the inverter and panels now, then that will reduce the price significantly, you can add batteries later, and if you do as much electrical work as you can whilst the sun is up and reduce your usage after hours (EG the dishwasher runs during the day, not overnight) then you will cut a chunk out of your power bill. At my home, in COJ, we would use 2 to 2.5 units per day on a sunny day in this scenario (what is called a grid-tied system). You can add batteries later. Note that you won't have any power if your supply is interrupted (but you won't be any worse off). 

It isn't cheap, so it's prudent to think on it and to do a bit of arithmetic. If load shedding returns then the equations change, because now you are not just saving, you are getting continuation of your life style.

All of the above require an initial outlay, with costs recovered over months or even years. And this is the reality of the situation. There are only a few things you can do to cut your bill that don't cost you at least some money. Even a timer switch on the geyser is going to cost something.

Edited November 6, 20241 yr by Bobster.

6 minutes ago, Bobster. said:

It's a tougher sell now that we don't have load shedding, though note that Eskom continue to say that load shedding is "suspended". They are not saying that we are out of the woods yet, though clearly there has been an improvement.

Get good ball park figures for a system. Then build a plausible model of increases in the cost of electricity, and try to get an idea of ROI. Then it may seem a more sensible choice. Then again it may not. You are trading a big lump sum now for steady - and increasing - savings each month for the next 10 years. Do not calculate on the basis that solar will reduce your grid usage to zero. It won't. The sun doesn't shine all day every day (well... if you're up in the NW hoekie of the country you are getting close), so work on 90% reduction in useage. 
 

Going whole house solar just is not an option right now, SO wants her new floors and her new cupboards in all 4 of the bedrooms of her house.. That is 100sqm worth of floor and 35k worth of cupboards.. I have done the calculations, shown her the ROI and what not.. Mind is made up, I have to move on..

In terms of water heating, that too is a bit out of reach, as I am ideally looking at going the heat pump route, with the magneto 200L unit.. That is 45k installed..

Therefore, it seems to me that getting the pool pump onto solar is the best ROI option.. Per my understanding, there are off-grid inverters that simply require solar panels and no battery to run.. So initial outlay for an inverter and panels to run the pool pump is something I am probably going to be able to sell to the SO..

24 minutes ago, slayer said:

Therefore, it seems to me that getting the pool pump onto solar is the best ROI option.. Per my understanding, there are off-grid inverters that simply require solar panels and no battery to run.. So initial outlay for an inverter and panels to run the pool pump is something I am probably going to be able to sell to the SO..

Just keep track of the electricity bill. Always handy to be able to put a number on the savings.

Owning a house is not for sissies.