According to the US Energy Information Administration’s (EIA) 2021 estimates, an average U.S. residential unit consumes 29.53kWh of electricity monthly. A 7kW solar array can produce 21 to 49 kWh of power in one day, so it can deliver what’s needed to most homes, even those with higher-than-average electricity consumption.
But how much does such a system cost? Is the initial investment worth the savings you will make on your utility bills?
At first glance, a 7kW solar system is undoubtedly a worthwhile investment. However, the cost of going solar varies widely, depending on several factors. So there’s no simple answer to these questions.
There’s a more pertinent question you need to ask yourself first:
Is a 7KW Solar System an Ideal Choice for You?
If you’re a homeowner in the United States, a 7kW solar system will likely deliver all your electricity needs.
But you need to do some math to arrive at a definite conclusion for your own household.
Residential electricity consumption has a wide range: it’s as low as 6,369 kWh per year in Hawaii to as high as 14,302 kWh in Louisiana. It’s safe to say your solar system should produce 18 to 40 kWh per day to offset your power consumption entirely.
A 7kW solar system, installed at a full tilt angle, can produce 7 kWh of energy in 60 minutes, when solar irradiance is 1 kW/square meter. So, a 7kW solar system needs 3 to 6 hours of exposure to peak sun hours to meet your daily energy requirements. Given ideal conditions, it can easily produce 21 to 42kWh of power, enough for most residential units in the country.
Do all states receive that many peak sun hours?
On average, all 50 states receive at least three hours of peak solar irradiation each day, whether it is summer or winter. This means that under ideal conditions, a 7kW solar system is a safe choice for you, even if you live in a state with relatively higher electricity consumption, like Louisiana.
What constitutes ideal conditions? For that, you need to know the following:
Factors That Influence Power Production of Solar Panels
For any solar system to function at its best and deliver optimum power, you must consider these factors:
Orientation
If your home is located in the northern hemisphere, your solar panel must face true south to maximize productivity. On the corollary, it must face true north if you live in the southern hemisphere.
If your solar panel is oriented towards the east or the west, it will produce roughly 20% less power than true north or south.
While you may not have the choice in terms of location or orientation, do your best to find the most optimal angle according to your area.
Tilt
The vertical tilt of your solar panels, or its angle, can affect its power generation capacity. Under ideal conditions, it should be the same as the latitude of your location, or as close to it as possible. However, the weather and the time of the year will also affect the tilt of your solar arrangement.
During summer months, when the sun is strong and high up in the sky, the tilt should be 15 degrees less than your latitude. Conversely, during winters, it should be 15 degrees more than the latitude.
Consult closely with your local solar expert for advice about the ideal tilt to make the most of your solar system.
Weather and Shading
The amount and intensity of sun exposure obviously impact the amount of energy a solar system produces. As mentioned earlier, a 7kW solar system needs at least three hours of uninterrupted exposure to peak sun hours to produce enough power to meet the average 30kW requirement.
Interruptions in terms of shading from trees or other nearby structures can reduce the overall efficiency of your solar arrangement.
Type and Efficiency of Solar Panels
Solar companies often boast about their panels, advertising up to 42% efficiency. But this does not imply that the solar panel will deliver this exact amount of power. It still depends on the cell layout, configuration, and type that truly determine how much power the system will generate.
Based on these factors, solar panels have an average of 16% to 24% efficiency. Let’s take a look at their individual configurations for better understanding:
| Cell Type | Mono PERC Cells | Poly PERC Cells | Half-cut Mono PERC Cells | Shingled Mono PERC Cells | Mono PERC MBB | N-Type TOPCon | N-Type HJT | N-Type Black Contact |
| Solar Panel Efficiency | 17% to 19% | 16% to 17% | 18% to 20% | 19% to 21.5% | 20% to 21.8% | 21% to 22.5% | 21% to 23% | 21% to 24% |
How Much Will a 7kW Solar Arrangement Cost?
Although more and more homeowners are going solar, supply chain constraints have increased the price of solar panels in the last two years. Per Solar Energy Industries Association’s (SEIA) data, you could expect to spend around $25,000.
The exact cost of a 7kW system depends on the following:
Manufacturer
The price of your solar array depends on the manufacturer and model you choose. For example, going with a popular and reliable manufacturer like SunPower could cost you $1.50 to $3 per Watt.
Similarly, monocrystalline solar panels are much more expensive because they are by far the most efficient.
Place of Purchase
You can buy your solar arrangement from a local dealership that offers discounts, directly from the manufacturer, or via solar cooperatives. In each case, the cost and mode of payment will vary. While you can surely get a great price if you’re purchasing via a solar cooperative, you may be able to get better EMI options when buying from a reliable manufacturer.
Federal and Local Discounts
The US federal government offers standardized solar credit across all states. Your local governing body may also add to the overall rebate upon solar installation. Some states have net metering laws, and others offer solar-specific discounts.
Soft Costs
You must also consider ancillary factors that will affect the cost of going solar. This includes installation charges, rooftop repairs, and solar inverters and batteries to supplement your PV arrangement.
Because going solar is so investment heavy, it’s best to do your research and create a detailed budget instead of rushing the process.
How to Fund Your Solar Investment
Thankfully, there are multiple ways in which you can invest in solar power without going broke.
You can apply for a loan, where you can make payments for each year as a part of your annual property taxes. New homeowners can also avail of solar and other upgrades up to 15% of the overall value of their homes.
Or, you can simply lease solar power. If you want to make quick savings without the hassle of making a huge down payment, try something like a Power Purchase Agreement (PPA). PPAs work like privatized net metering laws where you can pay a fixed tariff to buy solar power back from the grid. It’s a low-cost alternative to purchasing your own solar system.
Understand your options and weigh all the pros against the cons before making the final decision. Residential solar adoption will only increase in the coming years, and so will your funding options.
Authored by Ryan Douglas
NRG Clean Power's resident writer and solar enthusiast, Ryan Douglas covers all things related to the clean energy industry.
