Note: This guide is for learning. Our Home Zone page shows one example off-grid kit through an affiliate link, and we may earn a commission if you buy through it, at no extra cost to you. Our full disclosure is here.
Shop for a solar kit and you will see numbers like “10KW” and “9.36KWH” side by side. They look almost the same, but they measure two different things. If you mix them up, you can buy a system that is far too small for your house, or pay for much more than you need. This guide explains the basics in everyday words, using facts from government sources we checked on September 20, 2026.
kW versus kWh: speed versus distance
Think of a car. A kilowatt (kW) is like your speed at one moment. It tells you how much power something can produce or use right now. A kilowatt-hour (kWh) is like the distance you travelled. It tells you how much energy was used or stored over time.
Here is an example. A 1 kW space heater running for one hour uses 1 kWh. Run it for five hours and it has used 5 kWh. Your electric bill charges you for kWh, not kW. When a listing says “10KW Output,” that is usually about how much power the equipment can handle at once. When it says “KWH,” that number is about an amount of energy. Always read the listing to see what each number refers to, because sellers write them in different ways.
How much electricity does a home use?
The U.S. Energy Information Administration (EIA) reports that the average U.S. home electricity customer used 10,791 kWh in 2022, or about 899 kWh a month. If you divide that by 365 days, it works out to roughly 30 kWh a day. That last step is our own math, not the EIA’s. Your home may use much more or much less, so the best number is the one on your own electric bill.
Where does it go? The EIA says the three biggest uses of electricity in U.S. homes in 2020 were air conditioning at 19%, space heating at 12%, and water heating at 12%. Lighting and refrigerators came next. Weather changes these shares from year to year.
Grid-tied or off-grid?
A grid-tied system stays connected to the power company. An off-grid system stands on its own. Because the sun does not shine at night, an off-grid home needs batteries to store the daytime power. A typical off-grid setup has four main parts: solar panels that make the power, a charge controller that manages how the batteries charge, batteries that store the power, and an inverter that turns stored power into the kind your outlets use.
One point surprises many people. The U.S. Department of Energy says that residential solar panels alone are not enough to make your home resilient during a blackout, because panels are designed to switch off when the grid power cuts out. To keep power flowing you need a properly set up inverter and a storage system, such as a battery.
Five things to check before you buy a kit
1. Know what each number means. Ask what the “KW” and the “KWH” in the listing refer to, such as inverter output, panel capacity, or battery storage. If the listing is not clear, message the seller before you buy.
2. Compare it with your own use. Look at your electric bill for your monthly kWh, divide by about 30, and you have a rough daily number. A kit that cannot cover that number will not run the whole house.
3. Check what is in the box. Kits differ. Ask whether panels, batteries, inverter, wiring, and mounting hardware are all included. When your kit arrives, count every part against the listing right away, while returns are easy.
4. Plan for permits, rules, and a licensed electrician. Solar is a major home project. The Homeowner’s Guide to Solar points homeowners to questions about local incentives, net metering, and HOA restrictions, and notes that there is no one-size-fits-all solar solution. Check your local rules before you spend money.
5. Do not count on the federal tax credit. The IRS states that the Residential Clean Energy Credit is not available for property placed in service after December 31, 2025. A kit bought now would not qualify for that 30% credit. Some states and utilities offer their own incentives, so check yours.
Where our example kit fits
In our Home Zone we feature one example: an ECO-WORTHY off-grid solar kit sold on eBay. We have not tested it, and we cannot tell you whether it will cover your home. It is there so you can see what a complete kit listing looks like. Use the five checks above on any kit you consider, ours or anyone else’s.
Frequently asked questions
Will solar panels keep my lights on during a blackout?
Not by themselves. The Department of Energy explains that panels switch off when the grid goes down. You need a properly set up inverter and battery storage for backup power.
Do I need batteries for an off-grid system?
In most cases, yes, because you will want power at night and on cloudy days. The battery stores extra daytime power for later.
Is the 30% federal solar tax credit still available?
The IRS says it is not available for property placed in service after December 31, 2025. Ask a tax professional about your situation, and check for state or local programs.
The bottom line
Learn the two words first: kW is power at a moment, and kWh is energy over time. Then compare any kit to your own electric bill. Before you spend thousands, check what is in the box, your local rules, and whether the tax credit applies. For simple ways to lower your bill first, read our guide to cutting home energy use this winter, or browse the Home Zone.