Solutions
New Energy Solutions
Solutions
Brands
Solar Panels
Brands
Locations
About Us
About Us
Support
Need help?
Support
Learn
Featured Articles
Sizing Up A System
Finance & Rebates
Learn
What Size Solar System Do I Need?
Choosing the right size for your solar system can be daunting. Getting the right fit is crucial to maximising savings and fully covering your home’s energy needs. We'll help you determine the best solar system size for your household so you can feel confident in making an investment tailored to your needs and lifestyle.
Key Takeaways:
Saving Potential of Solar Panels: With government rebates and reduced solar panel costs, solar systems can pay for themselves in 3-5 years, potentially saving homeowners thousands over the system's lifetime.
Solar Panel Size Guidance: For a rough estimate, a solar system saves around $400 per kW annually and typically outputs four times its size daily. Many households now size systems based on 24-hour usage to boost savings with potential battery storage.
Panel Count and Efficiency: The number of panels needed depends on system size and panel efficiency, with options like high-efficiency panels reducing the total number of panels required. Premium panels often offer benefits such as longer warranties and better performance.
Maximum Solar Output: Proper placement and orientation of panels, especially with considerations like time-of-use billing and shading, can greatly influence savings. Solutions like microinverters can help maintain output in shaded conditions, ensuring efficient energy generation.
Roughly Sizing Up A Solar System
Roughly sizing up a solar system is easy; solar power can save you around $400 per kW per year, and a solar system will output around 4 times its size as a daily average.
For example, a 5kW system will output around 20 kWh a day and may save you up to around $500 every quarterly power bill. For many households, this rule of thumb is good enough to answer the question of ‘how much solar do I need?’
As solar power prices continue to fall and battery storage is now a realistic option for most households, we are now starting to size up nearly all of our solar systems to match your 24-hour usage rather than guessing how much solar you could use during the daytime.
Sizing Up A Solar System
The average size solar system we are now installing is around 8kW-10kW, or we fill the roof with panels where roof space is a limitation. The main reasons for this are:
Good-quality solar systems are significantly cheaper than they were previously
Feed-in tariffs are now very healthy, so it makes good financial sense to over-size your solar to reduce your power bill. With an over-sized solar system, many of our customers are enjoying a credit on their power bill every quarter (as in they are getting paid money from their energy retailer instead of having to pay a power bill)
Government rebates are still in place. The larger the system, the larger the rebate. The ACCC also advises the government to get rid of the rebates as soon as possible, and there is certainly a chance that this could happen.
Property prices are increasing so much that it is becoming a no-brainer to use some equity to replace your power bills for the coming decades and add value to your home.
Batteries have changed the market. Whether you buy one now or in the future, it’s advisable to install your solar system now with the presumption that you will store excess solar power in a battery at some stage. This means sizing up a solar system based on your 24-hour usage, and until you get the battery installed, you will get paid an excellent feed-in tariff from your energy retailer.
How Many Solar Panels Do I Need?
Once you know how much solar power you will need across an average day, you can determine how many panels you need to generate that energy. Most solar good panels are now rated 400W per panel, with highly efficient panels around 400W-420W. The solar panel size is around 1.7m by 1m.
Generally, high-efficiency modules are more expensive per panel. However, because you need fewer panels for the same output, it is often recommended to choose a panel such.
For example, if you use a 10kW solar system for your home, you could install 24 x 415W solar panels, rather than 29 x 350W panels.
It is recommended that you spend a bit of time on the phone so that we can discuss the various options and help you understand the value of the different technologies (and price points). Click here to request a callback.
How to Size a Solar Power System
We understand there is a lot of misinformation when it comes to sizing up a system, and this isn’t helped by salesmen trying to up-sell customers to large solar systems they don’t need. So, let’s look at sizing up a solar system in detail.
Yearly Solar System Output
According to the Clean Energy Council Guidelines, a 5kW system in Sydney should average 19.5 kWh a day, or 7117.5 kWh a year. The problem with taking a daily average is that a solar system will output more power in summer and less in winter. This becomes an issue for households with seasonal usage patterns due to heating, cooling, pool pumps, etc., resulting in one or two bills a year being significantly more expensive than the others.
Air conditioning and pool pumps often work well with a solar power system, as increased power usage over summer is compensated by increased output from the solar system. In contrast, heating in winter will often be turned on at night, making it difficult to run off solar panels. This can be an issue if you go off the average and expect a 5kW system to give you 20 kWh daily in June when your winter power consumption is predominantly at night.
When To Use Your Solar Power?
Perhaps this is an obvious statement, but solar power only works during the day. Without battery storage (now available), solar energy must be used in the home as it is generated. Otherwise, it automatically feeds out to the grid. Your energy retailer typically pays you around 5-8 cents per kWh for the power you sell back to the grid – a fraction of what you pay for your power (but at least it’s something). This means the main benefit of solar energy is that it directly reduces your power bill by being used in the home as it is generated.
To find out how much power you use during the day, read your meter in the morning and then again in the evening. Subtract one number from the other, which will tell you exactly how many kWh you have used during the day. Ignore the off-peak hot water meter if you have one, and if you have 3 meters for a 3-phase supply, make sure you add the three meters to include all of your usage. You may need to take these readings over many days to get a realistic average rather than just one point.
If you have time-of-use billing, the other option is to add the usage during the peak billing period with the shoulder billing period. This will give you your usage from 7 am until 10 pm, which you can multiply by 0.7 (or so) to provide you with your daytime usage.
Your Base Load
Every house has a baseload. This will typically include a fridge, freezer, lights and perhaps some appliances left on standby. Like many households in Sydney, no one is home during the day at my place, and we still manage to use 8kWh during the daytime. Divide this number by 4, and a 2kW system would take care of my baseload, saving me around $200 a quarterly bill.
Additional Usage
On top of the baseload, you can use appliances during the day. Look at the average daily usage figure on your power bill – how much of this can you move to the daytime to run on solar power? Without solar power, you may be running appliances at night during the off-peak billing period or paying little attention to when you use your power as you pay a flat rate for your power. How much power can you use during the day without too much hassle?
The most significant users of power in a typical home include:
Pool pumps
Spa
Air conditioning
Heating (can you turn this on with a timer so you come home to a warm house?)
Dryer
Dishwasher
Washing machine
Fish Tanks
Generally, we advise not to worry too much about lights when considering solar power. They use very little power compared to the above items and are typically on at night.
Also, remember that your power consumption will often change on the weekend, during the weeks of holidays you have each year and the odd day off from work here and there.
One final point – keep an eye on the future. A surprisingly large number of people we speak to are getting solar now. At the same time, they are employed in preparation for retirement or the expectation of a baby, when the mum (or dad!) will be home all day using power.
How Do You Estimate The Solar System Output?
The solar system's output depends on which way your roof is orientated, and now we are getting into the specifics of maximising the benefit of a solar power installation. The 1KOMMA5° Team will often advise people to go for a split array. Yes, having the panels facing north is best; however, this creates a rough bell curve of output that gives you a peak generation period during the middle of the day. Are you going to be able to use most of the solar power most of the time if you have an output curve like the one in the image below?
This is a 5kW system in March, turning on as the sun rises and turning off again at around 7 pm. As an aside, one of the most essential points from this image is the maximum output. A 5kW system rarely gets close to 5kW of production at any one time due to the angle and the orientation of the panels.
This system has produced 959W in 15m, around 3.8kWh in the middle of the day. This could be improved with sun tracking. However, the cost of installing and maintaining an array that follows the sun does not pay for the increase you will get in output. It is much cheaper to get a few extra panels.
Look at Google Maps (or get out a compass) to see what roof sections you can install solar panels on. Anything north of the west or east is usable.
Panels facing east will output more power in the morning, and panels facing west will output more power in the afternoon. CoNorthd to North, panels facing east or west will not output quite as much over a year. However, losses are not great, being more significant in winter when the sun is lower in the south and the north. The 1KOMMA5° Team have access to detailed aerial photos, and we can accurately measure your roof and provide advice based on that.
In most cases, having two strings of panels can be a good idea, giving you two smaller output peaks. This makes it easier to use solar power, and this is how you can maximise the benefit of your system and reduce your return on investment.
Do You Have Time-of-Use Billing?
Perhaps one of the most essential points is how much you pay for your power and when. If you have time-of-use billing, you are much better off generating solar energy in the afternoon during the peak billing period. If your panels face west or north, you will push the output of your solar system into the afternoon, and during summer, the output will continue until 8 pm.
If you have time-of-use billing, we usually say to take an average of 30 cents per kWh when estimating the potential benefit to your power bill.
Do You Have Shade?
According to Renewable Energy World, shading of as little as 9% of a solar system connected to a central inverter, can lead to a system-wide decline in power output by as much as 54%. The below image is a great example of how micro inverters can significantly increase output.
In this image, the system will be working at near maximum output, despite the patchy shade. With a string inverter, the system will be outputting almost no power because of the panels in the bottom right. I have heard a bit of talk about bypass diodes lately. It is important to state that bypass diodes are designed to help stop hot spots on panels from bird droppings and the like. They do not work in the same way as microinverters and will not help maximise output in shaded conditions like microinverters do.
If you have patchy shade, please call the 1KOMMA5° Team for more information. We have shade analysis tools that can help us provide professional advice on whether you need micro inverters or not, and to what extent shade will impact the predicted output of your system.
How Do You Determine What Size Solar System You Need:A Summary
We hope this information helps you cut through the sales talk. If it all gets too much, keep it simple; solar can save you around $100 per kW per quarterly power bill and will output around 4 times its size, doing more in summer and less in winter.
In terms of how many panels you will need, compare the different price points and consider whether it is worth looking at a premium panel. Some real tangible benefits include a 25-year product warranty, higher efficiency, and increased performance of premium panels such as the 1KOMMA5° Full Black Module.
Given this knowledge, you can get a good idea of how much solar power you might need. But remember, this is just a starting point! There's more to consider when designing a customised system to maximise energy savings.
Check out everything you need to know before investing in solar for your home. This in-depth guide walks you through all the nitty-gritty details to ensure your solar system perfectly fits your home and energy usage pattern.
If you are ready for personalised advice, we are here to help. If you have a few power bills ready and have read this article, we can help you find the right solution in minutes.
We work a little differently here at 1KOMMA5°; we help you find the right solution – without any pressure. We want you to make an informed decision, and we want you to buy the system that fits your requirements.
FAQ
Frequently Asked Questions about Installing Solar Power
There are great government rebates/incentives still in place for eligible households. Basically, the larger the panel array, the more STCs your solar system generates as it is based on the expected output of the system over time.
When you buy a solar system, the purchase price is normally reduced by the value of the STCs created by your system. You simply fill out a form on the day of installation to confirm that the system has been installed, and that’s it. There is no additional paperwork that you need to do.
Small-scale Technology Certificates (STCs)
Small-scale Technology Certificates (STC’s) – previously known as Renewable Energy Certificates or RECS – are created when a Renewable Energy System such as a Solar PV system is installed.
The number of STC’s depends on the predicted amount of energy generated and hence the larger the system the greater the rebate. In essence, one STC is created for every megawatt-hour of production capacity of the system.
This is further multiplied by the number of years the system is likely to generate energy (for home solar systems, this is usually 15 years, although the life of the solar panels themselves is considerably more than that).
This incentive program is being phased out until 2030, so each year the number of certificates your system is eligible for reduces.
STC Price
The system for trading and pricing STCs for small systems is managed by the Small-scale Renewable Energy Scheme (SRES).
STCs are bought by Liable Parties (usually electricity retailers) and must be surrendered at the end of each quarter. As the number of STCs that are required to be surrendered is a fixed amount each year, but the number of STCs created is variable, the price paid for STCs also varies and is determined by supply and demand.
The Federal Government legislated in 2010 a fixed price for STCs by implementing a Clearing House system where STCs can be bought and sold for $40. However, there is no requirement for Liable Parties to purchase from the Clearing House, so they are likely to only do so if there is a shortage of STCs or the market price exceeds $40. There is currently a surplus of STCs in the market which means the market price of STC’s below $40
The Feed In Tariff is only something you need to worry about if you don’t have battery storage.
The price your chosen energy retailer pays for any excess electricity generated from your solar panels is recorded as a credit on your power bill.
In NSW, solar power is fed into your home as it is generated and your household will use it first before you draw power from the grid.
This means that for every kWh of solar power used in the home you are directly saving money you’d spend on your power bill. This reduction in your power bill is the main financial benefit of solar power.
Everything else will be bought up at an agreed rate by your electricity retailer.
At the moment, most feed-in tariffs are between 5 and 10 cents per kWh, with many being about 7 cents. They bounce up and down a lot, for example in previous years they have been up over 20 cents per kWh. Typically, they are always at least 5 cents per kWh.
Once you sign up for a 1KOMMA5° Installation, we immediately submit your grid application to the relevant energy distributor. For systems up to 5kWs, this is a formality. For larger systems it can take a few days or more. Once we receive approval, your installation will be managed by our installation coordinator, who will welcome you to 1KOMMA5° and book an installation date for you. This is generally booked within around two weeks and installation dates are available Monday to Friday, weather permitting.
We endeavour to have your system installed within 2-4 weeks unless you request us to hold for whatever reason. Due to our strict safety policy, we do not install solar systems when it rains. In the event of inclement weather, we will rebook your installation as soon as possible. We always work with your requests as we strongly recommend that someone be home on the day of installation.
Green Loans can be an affordable way to pay for your solar power system and is only available for approved products. As a Clean Energy Council Accredited installer, all our systems qualify.
Green Loans can be used to finance 1KOMMA5° systems from $1,000 to $30,000 over a 2-7 year term. Once you have received a referral from 1KOMMA5°, online approval usually occurs within 1-2 business days. Green Loans have a competitive fixed interest rate that is as low as 7.99% p.a.* | Comparison rate 9.21% p.a.^ Establishment fee of $299 added to the loan amount. $2.70 per week account keeping fee included in repayments.
To be eligible to apply you must:
Be over 18 years old and an Australian resident or citizen
Own or be purchasing a home
Be employed, self-employed, a self-funded retiree; or is receiving the Government Age Pension
Have an Australian driver’s license or Passport
Provide two most recent payslips or 90 days of bank statements
There are a number of good, competitive Green Loan providers – ask us about the options available.
More Helpful Articles:
1KOMMA5° Blog
Need more information?
Head over to the 1KOMMA5° blog for more helpful tips and other important guides on everything solar, from inverters, panels and batteries to how to make the most of your investment for years to come.