A kilowatt-hour (kWh) is a unit of energy that represents one kilowatt of power used or produced continuously for one hour. It is the standard unit that appears on your monthly electricity bill and is the most practical way to measure how much energy your home consumes or your solar panels generate.
For perspective, one kWh is roughly the energy needed to run a window air conditioner for an hour, keep ten 100-watt light bulbs lit for one hour, or wash a full load of laundry. The average U.S. household consumes about 10,500 kWh per year, though this varies widely by region and home size.
Your electricity bill charges you per kWh consumed. In the Northeast, rates range from about 16 to 29 cents per kWh depending on your state — significantly higher than the national average. This makes solar particularly attractive in the region, as each kWh your panels produce directly offsets a relatively expensive kWh from the grid.
When evaluating a solar system, installers estimate how many kWh your panels will produce annually based on your location's sunlight, roof angle, and system size. An 8 kW system in New York might produce about 9,500 kWh per year, while the same system in Massachusetts might produce 10,000 kWh due to slightly different solar conditions.
Tracking your kWh production versus consumption helps you understand your solar system's performance and actual savings month by month.