Sizing Up The Solar System
Once we understand the output curve of a solar system, we can then try to size up a solar system so that you use most of the solar power over the course of the day to maximise the benefit of the system.
Most households will use more power than the solar system generates early in the morning and later in the afternoon, and a lot less than what the solar system outputs during the middle of the day. We expect most households will be able to use up to around 70% of the solar power in the home as it is produced, although many households do a lot better than this.
Having installed thousands of smart solar systems with online monitoring, we now have a very clear picture of how households tend to use electricity:
- The baseload: fridges, freezers, lights, fish tanks and anything else left running most of the time
- Daily usage: pool pumps, air conditioning, appliances such as the dishwasher, washing machine etc.
- Peaks: the toaster, hairdryer, heat lamps in the bathroom, a big air conditioner turning on
Typically when sizing up a solar system, we try to cover all of the baseload, plus as much of your daily usage as is practical/affordable.
The big spikes in power usage wont be covered by the solar system as it just isnt worth it. As an example, doubling the size of your solar system to cover a 10-minute spike of power usage from the bathroom heat lamps doesnt make financial sense.
The other factor to all of this is managing when you use your power.
Alternatives To Solar Panels
As solar technology has developed more people than ever are now able to enjoy the benefits of free renewable solar energy. So, if you can’t fit enough conventional solar panels to your roof, then flexible solar panels and solar roof tiles are alternative options.Flexible solar panels are a lot thinner and lighter than conventional panels which helps to make them much more flexible. This means that anyone living in a home with a roof that might not be able to support the weight of several solar panels doesn’t have to rule out renewable solar energy as a way of cutting their energy bills.
Solar roof tiles, or solar shingles, tend to be more expensive than solar panels, don’t generate as much energy and aren’t suitable for all roof types, however, they’re an aesthetically pleasing option that are popular as part of a roof replacement.
How Much Energy Is This
Typically, a 3 to 4 kW solar panel system will produce enough energy for a family sized home, while a 2 to 3 kW will typically be the right size for a smaller household.
An average 4 kW solar panel system will generate around 3,400kWh of free electricity a year. Thats enough electricity to individually power:
- 4,857 hours of the washing machine
- 97,143 hours of the fridge
- 1,880 hours of boiling the kettle
- 1,417 hours of the oven
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How Much Power Am I Using
A kilowatt-hour is a basic unit of energy, which is equal to power times time . Your electric bills show how the average number of kWh you use per month.
For example, a 50 Watt light bulb left on for one hour would be 50 Watt hours, and 20 50 watt light bulbs running for one hour would be 1 kilowatt-hour . According to the U.S. Energy Information Administration, the average monthly electricity consumption for a residential utility customer is about 903 kWh per month.
Divide your average monthly usage by 30 days in a month to get your daily usage. If youre going by the national average, then you should be using about 30 kWh per day. Next, figure out the average amount of sunlight you get per day. The US ranges from about 4 hours 6 hours of sunlight per day, on average, see the below map. Lets estimate you get about five hours per day to generate that 30 kWh you use. So the kWh divided by the hours of sun equals the kW needed. Or, 30 kWh / 5 hours of sun = 6 kW of AC output needed to cover 100% of your energy usage.
How Big Is A 4kw Solar System
Lets start with the obvious question: how big is a 4kW solar system? Well, lets look at a few different ways to measure a solar systems size.
What does 4kW actually mean?
In the solar industry, we talk a lot about kW or kilowatts, but what does it really mean? And how much is 4kW?
Kilowatts simply measures how much electricity something produces or consumes in one moment. You probably dont think about it, but youre already familiar with kilowatts. All your light bulbs are rated in watts .
Walk around and look at the top of your bulbs. If theyre LEDs, they probably say something like 9 watts or 9W. If theyre incandescent bulbs, they probably say something like 40W or 60W. This is how much electricity they need to turn on and run. Your hair dryer probably needs around 1500 watts. Cell phones typically need around 50 watts to charge.
To measure how much electricity something consumes over time, we use kilowatt-hours. So if you left your phone charging all night, it would consume 400 watts-hours of electricity . If you left your LED light bulb on 24/7, youd use 6,480 watt-hours of electricity each month .
Solar installations are different, though. The gadgets above consume electricity. Your solar installation produces electricity. A 4kW installation produces 4kW of electricity . How many kilowatt-hours does a 4kW system produce? It all depends on your location.
How many solar panels is that?
How much space does that take on my roof?
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Electric cars have several benefits over conventional internal combust engine automobiles, reduction of local air pollution, especially in cities, as they do not emit harmful tailpipe pollutants such as particulates , volatile organic compounds, hydrocarbons, carbon monoxide, ozone, lead, and various oxides of
How Expensive Is A 4kw Solar System
The next thing you probably want to know is how much a 4kW installation will set you back. The National Renewable Energy Lab studied installation costs for residential solar in 2016 and found the average cost for residential solar to be around $3 per watt.
Using this amount, we estimate that a 4kW installation costs about $12,000. If you own the installation , youre also eligible for the 30% federal tax credit, dropping your total installation cost to $8,400 .
Experts estimate that solar installations will last around 25 years, so how much does this total installation cost compare to purchasing electricity from your utility? Lets find out.
First, averaging out the annual production for the 3 locations above, we find that your installation will likely produce around 119,185 kWh over its 25-year life .
Now lets break down that cost and find your $ per kWh cost, which will allow us to compare your costs to the utility. Dividing $8,400 by 119,185 kWh, we find your costs will be around $0.07 per kWh.
With the average US utility charging $0.13 per kWh and that price rising 2.6% each year on average youll be immediately saving money pretty much anywhere you install . In fact, many states, local governments, and utilities offer tax credits, rebates, and other incentives to further drop your installation price, allowing you to save even more money.
At this rate, youre on track to save around $12,800 over the life of your installation!
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Forget Single Solar Panelshow Much Energy Will Your Whole System Produce
Knowing how much energy a single solar panel produces is all well and good, but more importantly, how much solar power can your roof generate? Lets do the math below:
Take our example above, where youre getting an average of five hours of direct sunlight per day and using solar panels rated at 290 W. Lets say you install 30 of those premium solar panels on your roofthat nets you a 8,700 watt, or 8.7 kW solar panel system, near the average system size purchased on the EnergySage Marketplace. Multiply the five direct sunlight hours we estimated above by 8.7 kW, and we get approximately 43.5 kWh of electricity produced per day. And for one final conversion, if we multiply 43.5 by 365 days in a year, we get approximately 15,800 kWh of electricity produced in a full calendar year from a rooftop array of 30 premium, 290 W solar panels. Considering the average electricity use per year in the U.S. is around 10,600 kWh, thats probably more than enough to power your home on solar.
This estimate is likely on the high end for most solar shoppers, and likely because of our estimate for the amount of sunlight the system will get . To learn more about average sun hours, check out our blog here, where we take a look at average sunlight per year by location.
How Do I Calculate A Solar Panels Output
Because every solar panel system is different, its hard to say exactly how much electricity yours would generate. This useful calculator by the Centre for Alternative Technology can give you a rough idea, as well as the amount of money you could expect to save.
There are also a few general benchmarks you can use to estimate your systems potential output.
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How Much Power Output Does Your Home Need
This all depends on two things: how much electricity you use, and how much of your home you want your solar panels to power.
If your household has a particularly high energy usage, or you want to solely rely on solar panels to power your home, wed recommend getting solar panels with a high output around 300 watts or more.
However, if you dont use much electricity day-to-day, or only want solar panels to subsidise some of your homes energy usage, you can choose solar panels with a lower output around 225 to 275 watts.
Most homes will install several solar panels, known as a solar panel system. A typical 3-4 bedroom house will require a 3-4kWp solar panel system, typically composed of 12-16 solar panels.
The output of a solar panel system can be calculated by multiplying the wattage of each solar panel by the total number of solar panels. For example, a home in Reading with four 250-watt solar panels would have a 1 kilowatt solar system .
Most domestic properties have between a 1kW and 4kW solar panel system, depending on how much power they need and the size of their roof. The table below shows you how much electricity different sized solar systems normally generate over a year, as well as how many solar panels theyre typically made up of:
|Solar panel system size|
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Is This Solar Panel Kit Right For Me
A 4kW Solar Kit requires up to 230 square feet of space. Ideal output will be achieved with an unobstructed south-facing view of the sun for maximum solar power. This 4kW solar kit provides 4,100 watts of DC direct current power. This could produce an estimated 300 to 750 kilowatt hours of alternating current power per month, assuming at least 5 sun hours per day with the solar array facing South. The actual power generated will vary based on location, equipment and installation factors. Refer to your electric utility bill to find the actual kWh used per month and compare it to how much power these low cost 4kW PV systems can generate.
The kWh generated monthly by these systems is great for eliminating the impact of a hot tub or running the air conditioner. A 4,100-watt Complete Solar Kit could offset 1/3rd of medium user’s consumption which may equal 1/2 their $ part of the bill.
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How Many Solar Panels Do I Need Then
Related:How many solar panels do I need?
Typically, a modern solar panel produces between 250 to 270 watts of peak power in controlled conditions. This is called the nameplate rating, and solar panel wattage varies based on the size and efficiency of your panel. There are plenty of solar calculators, and the brand of solar system you choose probably offers one. That said, there is a simple equation to calculate the amount of kilowatt-hours your solar panel system will produce.
So now that we know you need to produce about 6kW of AC output, we can work backwards to figure out how many solar panels you need. Solar panels produce direct current , and your home runs on alternating current .
Yep, like the band, AC/DC.
Because of physics, there are losses in converting the energy from the sun into DC power, and turning the DC power into AC power. This ratio of AC to DC is called the derate factor, and is typically about .8. This means you convert about 80% of the DC power into AC power.
This continues to improve ever so slightly, but the losses are unavoidable because of physics! So you take the AC amount you need: 6kW and divide by .8 . This means that youll need 30 250Wp solar panels or 27-28 270Wp panels.
How To Tell How Much Electricity Is Being Generated
When you go to have your solar panels installed, they will come with a meter that is placed in an accessible location within your home. What this meter does is record the amount of electricity that is being produced by the solar system, as well as how much electricity they are exporting back to the National Grid. This then allows you to work out how much you will be paid by the Feed-in Tariff.
Solar panel manufacturers are also starting to develop online apps for your smartphone that will allow you to access the performance levels of your solar panel. This can be done either via the app, or online from your computer.
To get the most out of your solar panels and the electricity that is produced by them, you should ensure that you use your appliances during the day as much as possible. This is because it is during the day that the panels will be generating energy.
You should also try to ensure that your home is as energy efficient as possible. This allows you to get the most out of your free energy. Try to use energy saving lightbulbs, and dont leave electronic devices on standby if you can help it, as these are all contributing factors to excessive energy consumption. Try, also, to only use the washing machine on a full load.
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Is A 4kw Solar System Worth It
With the average U.S. irradiance of 5.3kWh/m2/day , a 4kW solar system generates about 21.2kWh of energy per day, or 7738kWh/year.
This is quite a lot less than the average energy consumption for a U.S. home is 11000kWh/year. A 4Kw solar system may or may not meet a homes energy requirement, as it depends on the location and how much the home uses.
Whether such a system is worth it or not also depends on the electricity cost, which varies from state to state. The cost of the solar system must also be known, and this assest cost may be reduced by government or state solar incentives.
Make The Switch To Home Solar Today
Switching to solar energy is now more affordable and more accessible than ever! Renu Energy Solutions offers $0 down financing in available 4kW Solar PV Systems.
We understand every familys budget, energy goals, and priorities are different. Thats why we create a custom plan to reduce each customers electric bill.
How exactly does going solar and a solar system itself work?
How many solar panels do I need for my home?
Roof-size/available space: When we look at the size of your roof and the space available, we gather data that tell us the maximum number of solar panels your home or site can hold and we even consider shading. We use a software Suneye which takes a 360 picture of your roof and we use this photo to determine if your home is a good candidate for solar.
Energy Usage: When we determine energy usage we look at your past electrical bills from over the course of a year to make sure your system isnt too big or too small.
Your Budget: We take your budget seriously and most importantly, we want you to be satisfied with our services. We take your feedback on how much you want to spend so that we can size your system appropriately.
What is solar net-metering?
Does Duke Energy offer net-metering?
Curious about the cost of a home solar system?
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What Kind Of Household Does It Suit Best
If youre a small working family with electricity bills of $300 or more per cycle, the 4kW solar systems a great choice.
Choosing the right solar system for your needs can be overwhelming. And there are a lot of shonky operators out there. Thats why, when you call us on 1300 074 669, youll get reliable and trustworthy advice on choosing the right system for your needs. So come on, give us a call to get started.
Example Is A 4kw Solar System Worth It In Houston Texas
Calculate The Solar Payback For A 4kW Solar System In Houston, Texas
How many years to payback a 4Kw solar system in Houston?
What is the average solar payback period for a 4kW solar power system in Houston, Texas?
- City: Houston, Texas
- Solar system power output:4kW
- Solar installation cost = $10960 26% federal tax credit = $8110
- Irradiance level at Houston, Tx = 1552 Peak Sun Hours
- Power generated by solar panel system = 1552 x 4kw = 6208kWhrs
- Houston home electricity cost = 10.98 cents/kWh
- Yearly savings = solar output x electricity cost = 6208 x 10.98c = $690
- Solar payback time in Houston, Tx= solar cost/annual savings = 8110/690 = 11.75 years
The payback period might well be less than this, down to 9 or 10 years. Professional solar installers will give you accurate estimates based on their historical data, and the irradiance level in your geographic location.
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