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What are the most important factors to consider when going solar?

A lot of people are confused on these topics.

And there are plenty of misleading sales pitches out there to confuse them even further.

This article is written from my personal experience of trying to reduce a person's energy expense as much as possible, for as liitle as possible.

When choosing a solar system, to get the most value for money, you should consider the following factors in the following order of importance:

  1. The size of the system.
  2. The tilt and direction of the panels.
  3. Whether anything will permanently shadow the system.
  4. How much space is available.
  5. Warranties.

Battery Ready (separate topic) 


1. The size of the system.

For getting bang for buck, i.e. the biggest reduction in your power bill, the most important factor above anything else is the actual size of the system in kilowatts (kw).

Efficiency, type of panel, micro-inverters, optimisers etc etc are of a lesser-importance.

The kw rating of the system determines the maximum output of the system.  It's rather obvious but needs to be stated.  The more kw you have, the more power you can potentially generate.  Period.  The more power you generate, the more you will save on your energy bill and the more self-sufficient you will be. 


2. The tilt and direction of the panels.

The second most important factor is the tilt and direction of the panels.

The best yearly yield comes from tilting the panels at around 30 degrees due north.

However, having said that, pointing the panels east will give you a better yield in the mornings, and west a better yield in the afternoon.  Not everyone uses all their electricity in the middle of the day.

People usually use the most electricity in winter.  Having the panels tilted at 30 (or more) degrees allows more sun to hit the panels because the sun sits lower in the sky.  When they are flat, the sun sort of "skims" over the top of them in winter and there is a significant decrease in output (about 30% less from an actual test we did).  The generation is higher in summer when they are more flat.

Don't get too hung up on this.  Look at your budget.  If it is going to cost a fortune to tilt them it may be more economical to just put more panels up.  


3. Whether anything will shadow the system.

If there is anything  permanently  shadowing the roof where the panels are to go you will need to install a system with either micro-inverters or optimisers - micro-inverters being the preference.

Note I said permanently.

If you don't have any permanent shadows the above is an extra expense and frankly a waste of money.  For the extra money you are going to spend you would be far better off installing more panels instead.  Also, the extra electronics involved could actually reduce the efficiency.

The idea that a bird flying over your system, or that a cloud shadowing one panel etc, is going to ruin your production is a fallacy.   It's nothing more than a sales pitch.


A case in point. 
I recently had the experience of meeting someone who had had a salesman convince him he needed the latest and greatest LG panels with optimisers etc etc.   You know the story...  

I stood there horrified looking at this fellows roof with this array of panels lying relatively flat with a big smoke flue casting a shadow across a couple of them.  

My shock wasn't even that - it was more why the heck did they put them on  that  roof when across the way was another roof with a perfect north-facing 20-degree pitch and no shadows?  I guess you could argue it was a little more work to install them there, but still...

Anyways, he told me it didn't matter as the system has these amazing "optimisers" so the shadows don't matter and the pitch is of little importance.  He was convinced too - I couldn't even reason with him!  

I just stood there with my mouth wide open in shock.  The sheer idiocy of the whole thing!  Needless to say, he was somewhat disappointed with the production of his solar system...

We installed another "standard" system, standard panels, standard inverter, on the other roof.
Side by side we had these systems running.  Our system being only 5kw against this latest and greatest 5.8kw LG optimised system where ours was producing 40% more electricity that the LG and it was only two-thirds the price!.   For what he spent on that system he could have gotten something a hell of a lot better. 

The sad thing is that he was convinced he got the best value system by a clever sales pitch. 


4. How much space is available.

If you have a restriction on space you need to look at the type and efficiency of the panels. 

If you have a space restriction you should go for a perc-mono type panel.   They have a higher output per their surface area.  Meaning you need less space per kw.

They are slightly more expensive. 

If you don't have a space restriction don't worry about it.  Unless of course you have a preference for black panels for aesthetic reasons. 

Remember it is the size of the system in kw per dollar spent that is the most important factor.  If you can get more kw up for the same price then do it - you will save more on your bill.  


5. Warranties.

Most panels come with a 25 year performance warranty.  This is pretty standard. 

In my 9 odd years of installing solar, I have not had a single one of our panels fail.  However, we have primarily used the same manufacturer.  They are pretty robust.  They are also quite cheap to replace.  

It's what you are paying for the salesman, their advertising, and the installers that comprises a majority of your solar installation's cost.

Inverters are also easy to replace.  These are the most likely to fail so you want a good warranty on these.  Ten years is good.

We source our products from some of the largest solar manufacturers in the world.  Our inverters have a 10-year warranty and panels 25-years.  We use these manufacturers because they will repair/replace any faulty equipment even if for some reason we happen to be no longer around. 


Battery Ready

Another "sales pitch" I am coming across recently is that you need to make sure your inverter is battery ready.

All solar systems are "battery ready".  Yes, I repeat, all solar systems are battery ready!  No matter whether you install one now, or had one installed 20 years ago - your solar is battery ready.

This is because the technology has advanced where the battery systems can be completely separate to the solar system.  i.e. you can install a battery whether or not you even have solar installed.  Batteries used to be on the DC side of the installation (the solar side) but now they can also be on the AC side (the house electricity side).  

Of course it is much better to install the batteries at the same time as getting your solar installed as you will get a better price, even if only because the installers don't have to make another trip.  But the idea that a system is "battery ready" is a sales pitch meant to fool you, or convince you that you are getting something "extra", which of course you are not.

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By combining wholesale energy with solar, we make people self-sufficient while still being connected to the grid.

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