Whenever you are reviewing quotes for a solar system, you will see the abbreviations kW (which stands for kilowatt) and kWh (which stands for kilowatt hours.) But what exactly is a kilowatt? How about kilowatt hours? Knowing what kilowatts and kilowatt hours mean is especially crucial if you have or are planning to install a solar system at your home or business. After all, you will need to know how much energy your household consumes. This will determine how many solar panels your residence will need. Let’s look at what a kilowatt is, as well as kilowatt hours.
Definition Of A Kilowatt
A kilowatt is a single unit of energy, to measure the rate of power an electrical device (or load) uses. One kilowatt equals 1000 watts. A kilowatt is important as it is the base unit of routine measurement for electrical energy. Think of it this way: all the electrical gadgets in your home, ranging from large appliances to smaller items such as hair dryers, consume energy in watts. The longer an electrical device uses electricity, the higher the rate of power, or the greater the amount of power consumed.
What Is A Kilowatt Hour?
Now you know kW means kilowatt, how about kilowatt hours, or kWh? These terms are sometimes incorrectly used interchangeably, but they are different. kWh stands for kilowatt hours. A kilowatt hour refers to the total amount of electricity a system consumes or generates. In simpler terms, kilowatt hours is the measure of kilowatt units consumed over a period of time. For example, one kilowatt of power during one hour equates to consuming 1000 watts.
Different appliances have different amounts of energy consumption. For example, a 100-watt bulb needs about 10 hours to consume 1kWh. Compare that to a large appliance, such as an oven that would consume 1kWh in as little as half an hour.
How Are Kilowatt Hours Calculated?
Kilowatt hours are calculated very easily. You simply measure the amount of energy used if you kept a 1kW appliance for running the span of one hour.
Why It’s Important To Know the Difference Between Kilowatts Versus Kilowatt Hours
As noted earlier above, kilowatts and kilowatt hours are not the same. For example, 7kW is not the same as 7kWh. When looking at quotes for solar systems, it can be easy for those unfamiliar with kilowatts and kilowatt hours to confuse the two.
Solar Panel Output and Kilowatt Hours
One of the most common questions we at Atlasta Solar Center get asked is, “How much power does a solar panel produce?”
The answer is determined by several factors, such as the type of solar panel, positioning on the roof, access to sunlight, and overall maintenance and condition of the panels. Currently, most residential solar panels produce between 250 and 400 watts—this equates to 2.5 to 4 kWh per day—but this is under ideal conditions, such as perfect sunlight, panel temperature, and other factors.
Solar Panel Output: Calculating How Many Watts A Solar Panel Can Produce
To calculate daily solar panel output, you can use the following formula:
Hours of sunlight x wattage of your solar panel
Peak Sunlight Hours
How much sunlight there is where you live affects how much energy your panels produce. Peak sunlight hours refer to an hour where the intensity of solar irradiance (sunlight) hits an average of 1,000 watts (W) of energy per square meter. For example, Colorado receives an average of 6.5 peak sunlight hours a day.
Solar Panel Wattage
For our example, let’s use a solar panel with a wattage of 350 watts, which equates to 3.5 kilowatt hours. So:
6.5 peak sunlight hours per day x 3.5kW = 2,275 watts
Divide this by 1000 to determine kilowatts hours:
2,275 watts / 1000 = 2.2275 kilowatt hours
So, the number of kilowatt hours produced here is 2.27 kWh per day. For the annual amount of energy produced, multiply this number 365:
(2.27 kWh/day) x (365 days/year) = 828.55 kWh per year
Now you know how to calculate the output of a solar panel.
Average Household Electricity Consumption
According to the U.S. Energy Information Administration (EIA), the typical American household consumes 30 kWh per day; this equates to about 893-kilowatt hours (kWh) of electricity consumed per month. Of course, this amount will vary greatly from one house to the next, due to factors such as:
- Size of your home
- Amount and type of appliances
How Many Solar Panels Do I Need For My Home?
To calculate the actual amount of panels needed for your home, you must know:
- Your home’s average energy requirements
- Current energy use in watts
- Climate/ peak sunlight hours where you live
- Size and efficiency of the solar panels you’re interested in
To determine how much actual solar power your needs, refer to your utility bills, as you’ll need both daily and hourly energy usage. Use the following formula:
Household’s hourly energy requirement x peak sunlight hours for your area / panel’s wattage
= # of solar panels required for your home
As always, we at Atlasta Solar Center are here to help. We get that calculating these numbers can be confusing at first, especially if you’re new to the concept of kilowatts and kilowatts. Our experts know to properly calculate these numbers, while considering various factors such as roof size and pitch, panel type/ size, climate, etc.
Knowing the very basics about kilowatts and kilowatt hours can help you better understand how solar systems work, as well as how electric appliances are powered in general.
Choose Atlasta Solar Center For Your Solar Energy Needs
At Atlasta Solar Center, we understand everyone’s energy needs are different. Whether you want to power your entire home with solar, just several appliances or want to power your RV with solar energy, we can provide the solar energy solution that is best for you.
We understand that calculating kilowatts and kilowatt hours can be confusing, but our experts are here to help. We consider numerous factors about your property and energy needs.