On average a 3kW solar system will produce about 12kWh of DC or 10.8kWh of AC output per day, considering 5 hours of peak sunlight 1. Watt-hour (Wh)= The total energy produced or used in a specific period of time 2. Kilowatt-hour (kWh)= 1000Wh DC vs AC?. 3kW solar system will be enough to run a small 2-3 bedroom house. An easy way to find out if a 3kW solar system is enough for you is to check your previous month's electricity bill. If the total electricity consumption was between 300-320kWh then a 3kW solar. A 3kW solar system with the right size batteries can run any appliances in the house that you can think of. One thing to keep in mind, if the batteries are fully drained your output. A 3kW solar system is enough to run most of the basic household appliances and can decrease your electricity bill by 30-35%. But it's not the size of a solar system to run an average US.