6kW systems: what to know

If you’re shopping around for a solar energy system, determining the best size for your installation is vital to the success of your investment.

We’ll answer the most frequently asked questions about 6-kilowatt solar systems to help you determine whether one is right for you, your home and your energy expenses.

Key insights

• A 6kW solar energy system can produce almost enough electricity to power an average-size home.
• 6kW solar installations cost about $12,500 on average after a 30% tax credit.
• An average 6kW solar panel system can save you enough on utility bills to pay for itself in just under a decade.

How big is a 6kW solar system?

If you look at the wide range of solar panel system sizes in the U.S., a 6kW array is essentially right in the middle. Although it is tough to gauge a national average in the rapidly growing solar energy industry, 6kW is a fairly typical solar system size, often used to generate the approximate annual electricity consumption of an ordinary American home. (We’ll dive deeper into this later).

Although people with homes that have greater electricity demands may want to consider larger installations, such as 10 kilowatt-hour solar systems, 6 kilowatts of solar capacity is usually enough to help most homeowners save a significant amount of money on their electricity expenses.

Kilowatts (kW) measure the peak capacity of your solar panel system.

In the U.S., the majority of 6kW solar systems are grid-tied, meaning they send the excess electricity they produce back to the utility grid. If you'd like to install an off-grid 6kW solar system, you’ll need battery storage to capture the excess electricity production throughout the day for use in the evening and early morning hours.

As Daniel L., a licensed solar electrician in Denver, Colorado, explained to us, “You don’t need a battery for a 6kW system, but if you add one you can pivot off of the grid to keep your solar panels running during an outage or power your home with stored solar energy overnight.”

How much energy can a 6kW system produce?

The amount of energy a 6kW solar panel system can produce varies based on a number of different variables, including your roof angle, solar panel efficiency, local weather patterns, and shade from trees or neighboring buildings. However, your geographic location is the primary factor affecting your 6kW system’s real-world energy production because it determines the amount of peak sunlight hours available.

While some parts of the country are lucky enough to get as many as 6.5 peak sunlight hours each day in the summer, other locations are a bit more limited in terms of their total solar potential. To find your exact solar potential, we recommend using a resource such as the NREL’s PVWatts Calculator or the Global Solar Atlas (GSA).

According to the GSA, a 6kW solar system in cloudy Portland, Oregon, could generate roughly 7,333 kWh of electricity every year. However, in a more solar-friendly location like Austin, Texas, you can expect the same 6kW solar system to produce over 9,000 kWh per year of emission-free electricity.

» LEARN: How do solar panels work?

How much does a 6kW solar system cost?

Nationwide, the average cost of a 6kW solar system is right under $18,000, but with the federal solar tax credit applied, the net expense of a 6 KW solar system is around $12,500 on average.

Just bear in mind that the cost of a 6kW solar system depends on your location, method of purchase (i.e., paying cash vs. financing) and whether you qualify for any solar tax incentives or rebates.

» MORE: How much do solar panels cost?

6kW solar system prices by state

To give you a better idea of what a 6kW solar system might cost you, here’s a breakdown of average solar costs in different locations nationwide.

How much can you save on your power bill with a 6kW solar power system?

On average, a 6kW solar energy system can save you around $1,360 per year (or roughly $113 per month) on your electricity bill, assuming the system produces 8,000 kWh of electricity per year and your power company charges 17 cents per kWh (the national average at the time of publishing). Your results will likely differ, though.

To calculate how much you can save with a 6kW system, multiply its approximate annual electricity production by the average price of utility power in your area.

The amount of money you can save with a 6kW solar panel system really depends on the price of electricity in your area and how much power your system actually produces. (That’s why some areas help your solar savings to go further.)

How long does it take for a 6kW solar system to pay for itself?

If you spend $12,500 on your 6kW system and it saves you $1,360 each year, it will essentially pay for itself in a little over nine years. Just remember that every installation is a bit different, and there are other variables that may impact your return on investment.

For example, Richard, a ConsumerAffairs reviewer from New York, claimed his 6.8kW solar energy system had only ever produced a maximum of 5.2 kW. That’s why it’s better to base your calculations on real-world production numbers rather than your system’s theoretical capacity.

» MORE: Are solar panels worth it?

How many solar panels do you need for a 6kW system?

To calculate how many solar panels you need for a 6kW system, simply divide 6,000 watts (6 kilowatts equals 6,000 watts) by the wattage of the solar panels you’re using. If 6,000 watts does not divide evenly by your solar panel wattage, you can round up your solar panel count to create a system slightly larger. (For example, 18 350-watt panels create a 6.3-kilowatt system.)

» MORE: How many solar panels do I need for my house?

How much roof space do you need for a 6kW system?

You’ll probably need between 300 and 400 square feet of roof space to install a 6kW solar panel array if you use appropriately sized solar panels.

Although it is technically possible to create a 6kW system with 60 separate 100-watt solar panels, that’s not an efficient way to produce solar power. In addition to the large amount of square footage necessary to accommodate 60 solar panels, having that many different points of power generation leads to greater equipment requirements, less efficient production and added project expenses.

That’s why it’s generally a good idea to stick to 300- and 400-watt solar panels for residential installations.

One more note: While nearly every home has at least 360 square feet of roofing, it is important to remember that not all roof space can be used for solar panel installations. In the U.S., the ideal roof for solar is southern-facing and receives direct sunlight throughout the entire day all year long, so account for that before you start buying solar panels.

» MORE: Solar panel size and weight: a guide

Is a 6-kilowatt solar energy system right for you?

A 6kW system may be just right for people looking to reduce their home electricity expenses without going overboard. In other words, these systems are large enough to significantly offset the average home’s energy usage while keeping installation expenses relatively low.

Even if you don’t expect a 6kW system to generate enough power to cover your home’s full annual electricity consumption, it can still help you save a significant amount of money and pay for itself over time.

That being said, 6kW solar panel systems might not be right for people in homes that consume far more electricity than the average residence. So, if your home is on the large side or you have special energy requirements, like an electric car to charge, you may be better off going with a larger installation. (Alternatively, if you only need a small amount of electricity, a smaller system might be better for you.)

Given that solar panels are such a large investment, it’s often worth working with a solar energy company to make sure your system is the right size to meet your needs.