Updated on September 8, 2025
How big do you need your solar system to be? That’s the question, isn’t it? More than a few salespeople will tell you that you need a big one. Maybe you do. It’s also possible that you might not.
Everyone’s home is different, and everyone’s energy needs are different. Some people have a large house and a large family, some have a small house and are single. The simple fact of the matter is that, like so many questions in the solar industry, the correct answer to this question is:
It depends.
At PSC Energy, we are a top-to-bottom, in-house solar installer with years of experience in evaluating our customers’ energy consumption patterns.
You can’t install a solar system until you buy one. You can’t buy one until you know what size system you’ll need and what accessories you’ll need to go with it. You can’t determine that until you know your electricity needs, and you really have no idea what they are until you evaluate your energy consumption patterns.
Whew!
In this article, you will learn the following:
- What are Energy Consumption Patterns?
- How Do You Determine Your Energy Needs?
- How Do Energy Needs Guide Your Solar Purchase?
- How Do Energy Needs Affect Your Solar Installation?
- What Are Peak Sun Hours?
- FAQ: Consumption Monitoring
By the end of this article, you will have a comprehensive understanding of what to consider when shopping for a solar system.
What are Energy Consumption Patterns?
“Energy consumption pattern” is a fancy-pants phrase that folks in the solar industry like to throw around. It’s fun lingo once you get the hang of it. Give it a shot: energy consumption patterns. Fun, right?
It’s a phrase that refers to how a household uses energy every day.
- Energy = Electricity in your home. It runs your lights and appliances. Pretty self-explanatory, right?
- Consumption = How you use a resource. In this case, electricity.
- Pattern = We all know this one: it’s a repeatable design or sequence.
When you put them all together, we’re talking about how electricity is used repeatedly in your home.
Next time you talk to a solar salesperson, just casually drop the phrase into your conversation and wait for their reaction. It’ll be good.
If you’re interested in learning a bit more about solar panels and energy systems, you might want to check out the following article titled, Are Solar Panels Worth It in NSW, Australia? A Price Breakdown for 2025.
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How Do You Determine Your Energy Needs?
How do you use electricity?
Take some time to determine when you are typically at home and how much electricity you use during that period. The answers to the following questions are part of your energy consumption patterns.
- Daily Routine: What does your typical daily routine look like? Are you usually at home when the sun is shining, or does your energy usage peak in the evening? For most people, it’s in the evening.
- Appliance Usage: Consider the appliances you use and the times you operate them. Are you running energy-intensive appliances during the day, or do you primarily use them in the evening?
- Seasonal Changes: Consider the seasons. Your heating and cooling requirements vary with the weather. For example, you may use air conditioning more in the summer, affecting your electricity consumption differently than in the winter. Also, your lighting preferences will change with the season. You’ll need light after 5 PM in the winter.
- Seasonal Activities: Consider any seasonal activities that may affect your electricity usage, such as the increased use of a pool pump in the summer.
The energy consumption patterns of most households tend to follow a similar pattern. Homes in the Sydney metro area typically use electricity in the morning and in the afternoon/evening hours, as residents often work or attend school in the middle of the day.
It’s as simple as figuring out a few key questions and answering them.
If you’re interested in learning a bit more about weighing the cost of solar against the cost of the grid, you might want to check out the following article titled, Cost of Solar Panels vs. Cost of Energy from the Grid.
Ready to go solar? Click here.
How Do Energy Needs Guide Your Solar Purchase?
The more energy you use, the larger the system you’ll need to save money and reduce your reliance on the electric grid. Similarly, the less energy you use, the smaller the system you’ll need.
However, we recommend installing a system that is easily expandable in the future, as electricity needs may change drastically even in the future, as the current energy crisis unfolds.
Families with school-age children will most likely use more energy in the morning than households without children. Kids wake up early and turn everything on. Parents are pretty likely to cook breakfast for kids and themselves, whereas a couple living together might skip turning on the TV and have coffee for breakfast.
Both types of households will undoubtedly use a lot of energy in the evening. The family gets home from school and work and needs electricity to see them through the evening hours just as much as a household without children.
Households with infants, people who work from home, and households with retirees are a different story. If a household has small children and a parent is home all day with them, then the electricity needs will be different throughout the day. The same applies to individuals who work from home and retirees who spend their days at home.
Solar systems with the best return on investment are those that most closely match the solar output to the household’s energy requirements.
Not long ago, solar companies were suggesting a 6.6kW system for most households. These systems were easy to connect to the grid and get permission to hook up with a 5kW inverter. A 6.6kW solar system outputs approximately 26kWh of energy.
Today, most households really need a system larger than that. Times have changed. Australians are investing in bigger systems because electricity is getting more expensive. Their needs are also greater. Their needs in the future are estimated to be even greater, with the emergence of electric vehicles and other home energy solutions.
Be careful when shopping for quotes because a lot of janky solar companies still recommend a meagre 6.6kW system.
Homeowners frequently choose a larger system size to accommodate potential growth in energy usage. Several factors can significantly increase your home’s electricity consumption.
These include installing an air conditioning unit, adding a granny flat or second dwelling, putting in a swimming pool, converting gas to electric (stove, hot water, heating), working from home, buying an electric vehicle, or installing a solar battery.
If you anticipate incorporating any of these plans into your home, it’s a good idea to consider adding more capacity to your solar system upfront. This helps avoid a more costly process of expanding the system later on. At the very least, consider investing in a microinverter system, which is exponentially easier and less expensive to upgrade than a string system.
If you’re interested in learning why other solar companies recommend a string system, you might want to check out the following article titled, Why Do Companies Sell 6.6kW String Systems with 5kW Inverters?
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How Do Energy Needs Affect Your Installation?
Because you use electricity primarily in the morning and afternoon/evening, you might want to consider installing panels to match that consumption pattern: one-third of the panels are placed on the eastern roof, and two-thirds on the western side.
It keeps the home running well from morning to evening based on energy consumption patterns. More energy is used in the afternoon, so this design benefits from that.
At PSC Energy, we call this the 2/3 rule. A third of your total solar panels should be installed on the eastern-facing roof to capture the sunlight in the morning when your household is getting ready for the day.
Two-thirds of your solar panels should be installed on the western-facing part of your roof to best capture the sunlight from the sun as it makes its way to the horizon, powering your home after you get back from work.
This doesn’t mean that the north-facing rooftop will be ignored. If there’s room on the northern-facing part of the roof, then that real estate should be used.
Realistically, most rooftops require as many solar panels as can be installed for maximum efficiency. Rooftop space is limited by the home’s design.
Not everyone uses energy in the middle of the day, so having energy in the afternoon is crucial if you don’t have a battery. A mix of east and west-facing panels can be a smart choice for solar efficiency, especially if you use energy later in the day.
Once you start to evaluate your energy consumption patterns and what your energy needs truly are, you’ll begin to understand that northern-facing panels aren’t the only place to install solar. East/west panel installation might be more efficient than northern-facing panels, depending on how you use energy.
If you’re interested in a deeper perspective and more specific examples of how energy consumption patterns affect your solar panel placement, you might be interested in reading this article titled, Can You Install Solar Panels on a South-facing Roof in Australia?
Power up your savings. Click here.
What Are Peak Sun Hours?
Finally, you need to determine how much electricity your solar system will be able to produce (on average, not accounting for seasonal changes). Bigger solar systems produce more energy than smaller systems.
Several other factors influence the amount of electricity these panels can generate. One of the most important factors in calculating how much that system can output is determining peak sun hours.
Peak sun hours are the time of day when your solar panels are most efficient. The average peak sun hour timeframe is approximately 3 –5 hours during midday. Non-peak hours are all the other hours in the day when the sun is shining on the panels but not at its maximum efficiency.
Peak sun hours are a crucial factor in determining the amount of electricity your solar system will generate for your home. It’s the amount of time when the intensity of the solar radiation (we’re talking about sunlight here) is, on average, 1000 watts of energy per square meter.
A peak sun hour is 1000W per square meter of sunshine for 1 hour.
This is how we do the math to figure that out:
Peak sun hours x solar system kilowatts = amount of kilowatt hours it can produce daily.
Peak sun hours are necessary for determining if solar panels can generate enough power to run your home and provide a return on investment. The amount of sunlight a home receives, along with the intensity of the sun’s rays, depends on its location.
Knowing the average peak sun hours for your home’s geographic location is necessary to determine how many solar panels will be installed on your roof. You need to calculate how many kilowatts your house will use in a day, which will inform choices about how many solar panels will be required.
Because you don’t know how many solar system kilowatts you have (because your solar system is not yet installed), you’ll have to rearrange the above equation to figure out your solar system size. It’s just like math class when you were in school, trying to figure out the missing integer.
You have the number of peak sun hours for Sydney, and you know how many kilowatt-hours your home produces in a year (because you read it on your electricity bill). The equation for determining the number of kilowatts your solar system will need to output is as follows:
Kilowatt hours your home produces daily / peak sun hours = daily solar system kilowatts.
In Sydney, the peak sun hours are 3.9. The peak sun hours are the maximum efficiency of the panels (on a sunny day) that your solar system will output.
Over the course of one year, your home used 10,000kWh of electricity (we’ll use a nice round number, so the math is more straightforward).
You start by dividing 10,000kWh / 365 days in a year to determine that you will use (on average, not accounting for seasonal changes) about 27.4kWh per day.
Next, you take the 27.4kWh per day and divide it by / 3.9 peak sun hours per day to get = 7.03kW. You need a solar system that produces at least 7.03kW every day to power your home.
In the summertime, there will be more peak hours, and in the winter, there will be fewer.
The sun’s intensity varies throughout the day, depending on the time and weather conditions. Your panels may only output 500W/meter squared at 8 AM and again at 5 PM.
Peak sun hours give us the best idea as to how much electricity a solar system can generate on average in ideal conditions.
Harvesting that energy in ideal conditions also depends on several other factors, including latitude, longitude, pitch, orientation, and azimuth.
For more insight into how the placement of your solar panels affects the efficiency of your solar system (and what all those fancy words we just used in the previous paragraph mean), you might want to check out the following article titled, Which Way Should Solar Panels Face in Australia?
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Energy Consumption Patterns: Wrapping Things Up
By thoroughly reviewing and assessing your electricity needs, you’ll have a better grasp on what you need from a solar system.
A reputable installer is a crucial component of the solar shopping process. A good installer will ask you questions about your energy consumption patterns to determine your unique needs.
If they don’t, you might want to find someone else to talk to about your solar purchase. How you use electricity influences every choice you’ll make about your solar system.
At PSC Energy, we want to inform you about every step of the process when it comes to installing solar on your home. We want you to understand that your needs are unique, and we’re here to help you on your solar journey.
If you’re interested in learning a bit more about your energy needs, you might want to check out the following article titled, How Much Solar Do You Need?
FAQ: Consumption Monitoring
How do I figure out what size solar system I need?
Start with your energy consumption patterns. Look at when you use power and how much you use in a day. Then match a system size that can cover that daily use during your local peak sun hours.
What are “energy consumption patterns”?
This is how your home uses electricity. These patterns include when you are home, which appliances you run, and how seasons change your heating, cooling, lighting, and pool pump use.
How do I assess my energy needs at home?
Check your daily routine, list your big appliances and when you use them, and note seasonal changes. Read your power bill to see average daily kWh. That number guides your solar size.
How do my energy needs guide the system I buy?
More usage needs a larger system. Less usage needs a smaller system. Choose a size that matches your needs now and leaves room to grow if your usage will increase.
Should I plan for future growth?
Yes. Many homes add loads later. Common growth drivers include air conditioning, a pool, converting gas to electric, working from home, buying an EV, adding a battery, or building a granny flat. Plan extra capacity or choose gear that is easy to expand.
Is a 6.6 kW system still enough for most homes?
Often not. Many households now need larger systems because electricity costs have risen and home loads have grown. Be careful with quotes that push a one-size-fits-all 6.6 kW system.
Which inverter type is easier to expand later?
A microinverter system is much easier and less expensive to expand than a string inverter system. It lets you add panels in smaller steps as your needs change.
How do energy needs affect panel placement?
Match panel direction to your usage. If you use more power later in the day and do not have a battery, an east–west layout can better cover mornings and afternoons.
What is the “2/3 rule” for panel placement?
Place about one-third of panels on the east to cover morning use and about two-thirds on the west to cover afternoon and evening use. Use north roof space as well if you have it.
What are peak sun hours?
They are the hours when sunlight intensity averages 1,000 watts per square metre. Most locations get about 3–5 peak sun hours around midday on a clear day.
How do I use peak sun hours to size my system?
Use this simple formula: daily kWh you use ÷ local peak sun hours = kW of solar you need. This gives a starting point before you adjust for roof space and layout.
