The average cost to install solar panels in the United States is around $12,000 after federal tax incentives. It can be more expensive depending on whether you're fixing up your current house and putting them on the roof or building an all-new home with them included in the specs - but it can also be cheaper. Smaller systems range from about $5,000 to $10,000, while others can cost upwards of $40,000 or more if they are tier 1 solutions.