One of the most common questions asked by customers is, “will a 10kW solar kit be enough to power my home?” For the average home in the USA, the answer is probably yes, but it will depend on several factors.
So first let’s understand how a solar system is sized and what that means. We’ll look at four topics to answer this question:
- How power is measured in kW vs kWh
- How is the size of the solar system calculated
- What does the solar system produce
- How to work out the benefits and savings
Now let’s take a look at each topic in more detail.
A KiloWatt, or kW, is the power used by an appliance or produced by the solar kit. 1kW is one kilowatt or one thousand watts. Most homes can accept from 24,000 watts to 48,000 watts of power from the utility at any moment. For example, if your home has a 100 Amp electrical panel that can handle up to 240 Volts, then the house can accept up to 24,000 watts (100A * 240V) of power from the utility at any moment. 10kW is 10,000 watts. If a microwave oven requires 1,000 watts, then 10kW would power 10 microwave ovens running at the same time. That is probably more power than you’ll need at any one time.
Now, a KiloWatt Hour, or kWh, measures energy as kilowatts are used over an hour. 1kWh is one-kilowatt hour, or one thousand watts for an hour. Your utility bill is measured in kWh every month. The average home uses 30kWh per day or 916 kWh per month or 11,000 kWh per year.
kW and kWh is the difference between power and energy. So when you buy your energy from the grid, you buy the kWh.
Solar Panels are established by their power rating. However, this does not mean they will produce that power at all times. The rating is established in a factory environment under ideal conditions. Throughout the day, as the Sun and seasonal factors change, the amount of power (kW) generated by the solar panels will vary.
To estimate your solar system size, you will need three pieces of information to calculate the solar kilowatts.
1. Your utility power bill for the last 12 month.
Some power bills have a summary chart. You might find your kWh there. The summary chart may show the average daily kWh used for the past 12 months. If so, you can enter the total kWh for the year. If no total is provided, then add the kilo-watt hours for each month.
2. The solar hours per day for your location
See our Calculate Solar Page to find your state and nearest city for the solar hours.
3. The percentage amount of the power bill you want to be covered
The amount of your electricity bill you want to cover. 50%, 80%, 100%, 150%; It’s up to you.
Our Calculate Solar Page has the power calculator ready for you to use with just a few simple steps!
Your solar array will produce energy based on what the environment is providing. If we use the 10 kW solar kit example, sometimes the kit will produce less than 10 kW, and other times, it may provide more than 10 kW.
You buy your energy by the kWh, which is important to remember when looking at what the solar kit will produce for your home. The energy produced at a specific moment in the day is less important than the kWh produced over the course of the month, season, or year.
Looking at a 10 kW solar kit, you can expect it to produce 30 to 45 kWh daily or approximately 11,000 to 17,000 kWh over a year. The energy produced will vary with the weather (sunny vs. cloudy day), the season (summer vs. winter), and the location (Florida vs Ohio).
The average solar hours per day in Ohio is approximately 4.68 hours, while in Florida, it is 5.77 hours per day. Therefore, residents in Florida experience longer solar hours each day, giving them more time to capture solar energy. While residents in Ohio have a smaller window of time for solar hours each day, they need to maximize their potential to capture energy within a shorter time frame.
Living in Cleveland, OH, there are 4.68 solar hours in the day. If the home uses 13,000 kWh per year, then a 10 kW solar kit will meet this home's needs to cover 100% of the power bill.
However, living in Miami, FL, there are 5.77 solar hours in the day. If the home uses 13,000 kWh per year, then an 8 kW solar kit will meet this home's needs to cover 100% of the power bill.
This means that in Florida, homeowners can use an 8 kW solar kit to capture the same amount of energy that a home in Ohio needs a 10 kW solar kit to capture. When determining the size of a solar kit, your location and energy requirements are major considerations.
If you buy a smaller solar kit than you need, your solar kit won’t meet your needs. Conversely, the excess energy will be lost if you buy a solar kit that is too large for what you need. You can add a battery storage system to provide power on demand and serve as a backup source in the event of grid outages. The peace of mind will go a long way.
A free way to determine your solar kit needs is to visit our Calculate Your Solar page and follow the instructions. We also have a helpful video to show you how to complete the solar calculator. However, the best way to determine what size of solar kit will work best for you is to purchase a Solar Consultation and Design. The consultation cost is credited back to you with the purchase of a 5kW solar kit or greater. Our experts will assist you by working out all the details to find the best solar kit for your home and budget.
In the perfect scenario, if you use the energy you produce at the time the energy is generated, you would have a zero energy balance. However, what is more likely, is that you are either using less energy than you are producing, in which case you sell energy back to the grid, or you use more energy than you are producing, in which case you buy energy from the grid. Your electricity rate schedule establishes the rate you sell your energy to your electricity company.
If your kit produces 40 kWh per day, this is 14,600 kWh/yr. If you pay 20 cents per kWh (14600 x .20), you will save $2,920 per year having solar. If you pay 30 cents per kWh (14600 x .30), you will save $4,380 per year. If you don’t use half of the energy you produce, and your rate schedule sells energy for 10 cents per kWh, you would receive $720 per year.
The reality is that no one uses all of their solar energy, nor do they sell all of their solar energy. Energy buying and selling are averaged over the course of a year. This is why energy companies reconcile all the cumulative energy charges, credits, and compensation for an entire 12-month billing cycle once a year. So instead of focusing on what your solar kit produces each minute or hour, it is best to see what it produces over a season or a year.