Solar panels on a whole house

Salmank

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Jun 27, 2016
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206
#1
Hi,

If I no more want to pay electricity, is it possible to put the whole house into solar?

What are the best options to generate my own electricity for a 400 square meter house with 2 geysers and a pool pump plus outside lights?
 

signates

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Dec 8, 2009
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#2
Hi,

If I no more want to pay electricity, is it possible to put the whole house into solar?

What are the best options to generate my own electricity for a 400 square meter house with 2 geysers and a pool pump plus outside lights?
You need to calculate your usage first to determine the best size for your system.

Get an energy monitoring tool to track your usage over a few weeks. I have an efergy home electricity monitor that's tracks my current usage and peak kw.

I use about 900kwh per month with peak power of 12kw.

I would also first look at getting an evacuated tube solar panel for your geysers.
 

Marsie27

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#3
This might give you some sort of idea of likely savings. We had 5 years municipal records prior to our solar geyser installation in Dec 2009, and have kept track since then. Apart from visits from family (probably 3-4 weeks annually) and friends, and our trips (probably 3-5 weeks annually) our 2 person household has remained constant.
1538492684818.png
 

Marsie27

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#4
The average daily kWh are 15.634 pre-solar geyser, and 10.718 post installation. Adding that in the screenshot made the figures a bit small to be legible.
 

Marsie27

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#6
Yes. E.g. October average14.3kWh per day pre-solar, 10.5kWh per day average after solar geyser installation. We have the evacuated tube system that Signates mentions.
 

maumau

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#7
Yes. E.g. October average14.3kWh per day pre-solar, 10.5kWh per day average after solar geyser installation. We have the evacuated tube system that Signates mentions.
Hmmm that is nice. Didn't realise that would happen.
 

spiff

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#8
Hi,

If I no more want to pay electricity, is it possible to put the whole house into solar?

What are the best options to generate my own electricity for a 400 square meter house with 2 geysers and a pool pump plus outside lights?

start by getting a solar geyser installed - no need for electricity to heat water so you can take that out the equation

next look at gas stove / gas heater / gas booster geyser - again take electricity out of the equation

look at LED lights - this will reduce your electricity cost even further

get energy efficient appliances - this will reduce your electricity cost even further

once you have reduced your electricity consumption - then do an energy audit to determine what size panels you will need.

the pool pump will be a problem - but there is a gadget that can run your existing 220vac pump direct from solar but it is expensive at R25k - panels excluded! see attached pdf
 

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SauRoNZA

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#9
This might give you some sort of idea of likely savings. We had 5 years municipal records prior to our solar geyser installation in Dec 2009, and have kept track since then. Apart from visits from family (probably 3-4 weeks annually) and friends, and our trips (probably 3-5 weeks annually) our 2 person household has remained constant.
View attachment 561427
What unit of measure are we looking at here?
 

Marsie27

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#10
What unit of measure are we looking at here?
kWh used per day i.e. the "units" that come on a municipal bill, or get bought for a pre-paid meter, averaged according to the number of days in the month. As in the heading on the table. This is actual usage, not the units we bought.
We have a pool, but we've had a cover for all the years referred to in the table, so we have to filter less as the water stays cleaner. And most of the time it's just the 2 of us using it.
 

SauRoNZA

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#11
Solar reduced your usage?
What
kWh used per day i.e. the "units" that come on a municipal bill, or get bought for a pre-paid meter, averaged according to the number of days in the month. As in the heading on the table. This is actual usage, not the units we bought.
We have a pool, but we've had a cover for all the years referred to in the table, so we have to filter less as the water stays cleaner. And most of the time it's just the 2 of us using it.
Then it makes even less sense.

How do you use 15701 kw (Jan B2) units in a month?

Or is it 15.70 units per day averaged out? Because then it's your comma separator that is confusing with three decimals as that implies a thousand.
 

Marsie27

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#12
We got a flyer in our letterbox yesterday that states that "more than 1/3 of your electricity bill is spent on heating water". That at least is a halfway-realistic comment. I get annoyed by companies that make bald statements that you WILL save 3/4 of your electricity bill. It might of course be true in some cases.
 

Marsie27

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#14
What


Then it makes even less sense.

How do you use 15701 kw (Jan B2) units in a month?

Or is it 15.70 units per day averaged out? Because then it's your comma separator that is confusing with three decimals as that implies a thousand.
Ah OK it's a screenshot from an Excel table with Excel's idea of a decimal indicator. Is this less confusing?

1538498002707.png
 

SauRoNZA

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#15
Ah OK it's a screenshot from an Excel table with Excel's idea of a decimal indicator. Is this less confusing?

View attachment 561465
Now it makes more sense just looking at it at first glance. :)

That's pretty low usage even before solar especially through winter. I would probably not even have bothered with the geyser setup if my usage was that low to start with.

Don't you run any heaters or things in winter? Or just all on gas?
 

Marsie27

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#16
No gas. We have a wood-burning stove in the lounge, as well as a fairly well-insulated house. We are in Cape Town, so don't have the extreme temps of the inland cities. No aircon. We have electric blankets in the beds, so don't use electric heaters. Yes, your comment re the costs of solar vs our usage is valid. We had recently put in a new copper-lined geyser (which we still have), so it was the costs of the panel plus some plumbing and fitting. I'd need to analyse what we would have got had we invested that money, relative to what we have saved. But we took the conscious decision to do it for ecological reasons, not primarily to save money.
 

SauRoNZA

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#17
Yeah I’m also in Cape Town and lean to 28 units average per day.

Wall panel heaters in three bedrooms and brief firing of air con in the lounge.

Summer we are at about 18 a day.

I am however inclined to also retro fit the geyser and down the line put a Powerwall 2 and solar panels in just to stick it to Eskom and also to use especially air cons more liberally in summer.
 

maumau

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#18
What did you expect to happen?
Thought it would stay the same, or if it were me I'd use more knowing I'm not paying for electricity.

..... or is he not off grid and only talking about municipal usage.... ah, that must be it!
 

SauRoNZA

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#19
Thought it would stay the same, or if it were me I'd use more knowing I'm not paying for electricity.

..... or is he not off grid and only talking about municipal usage.... ah, that must be it!
I guess you were thinking along the lines of solar electricity powering the geyser? That doesn’t apply because the tech used for the geyser heats the water directly and so no power is used and therefore the reduction in usage.

But yes your logic is same as mine for wanting a Powerwall and solar so I can actually use more power and run my aircons all day etc.

Right now because I pay for every bit I tend to only use them very frugally when absolutely cooking.
 

The_Traveller

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Aug 9, 2008
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#20
Hi,

If I no more want to pay electricity, is it possible to put the whole house into solar?

What are the best options to generate my own electricity for a 400 square meter house with 2 geysers and a pool pump plus outside lights?
Anything is possible with unlimited funds.

In your case you would need to invest around R500k to be totally off the grid.
 
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