The cost of installing solar panels can vary widely, depending on several factors, but on average, homeowners can expect to pay between $15,000 and $30,000 for a complete solar panel system. For a typical 2000 sq ft house, this translates to approximately $3 to $5 per watt. A standard system size for a home of this size usually ranges from 5 kW to 10 kW, which means you would expect to install between 15 to 30 solar panels, depending on the specific energy needs and panel efficiency.