Because 3 kilowatts is 3,000 watts, simply divide 3,000 by your panel capacity to determine how many panels you need. Wondering if a 3-kilowatt (kW) solar system is large enough to power your home or too large for your do-it-yourself (DIY) project? Below, we'll outline everything you need to know about 3-kW solar systems, including what they can power, how much they cost and how to determine if they're the right. How Much Does a 3 kW Solar System Cost? Based on the U. 66 per watt, a 3 kW — or 3,000 watt (W) — solar system costs an average of $7,980, or $5,905 after factoring in the 26% federal solar tax credit. The solar tax credit is expected to drop to 22% in 2023, so the. A 3kW solar panel system can power the average three-bedroom household, on a typical day. This amount of electricity can power a washing machine, tumble dryer, electric shower, hairdryer, oven, toaster, microwave, TV, games console, laptop, and light bulbs for certain amounts of time. Now you must be clear that with a 3kw solar panel how many units per day can be produced? What are 3kW Solar System Features? An on-grid solar system is one that works with a power.