How much do solar panels cost in Litchfield Park, AZ? The average cost of solar panels in Litchfield Park, Arizona is $14,350. Costs ranged from $12,198 to $16,502 in 2018-2019 according to EnergySage. These costs do not include the Federal Investment Tax Credit of 30% or other local incentives. The average payback period for solar panels in Litchfield Park took 7.62 years and the average electricity savings from solar panel installation was $49,166 over a 20 year period. The average cost per watt is about $2.87 a watt. This study included installation of a 5kw solar system, a slighty smaller than the average system size. Use our solar panel cost calculator to find out your solar system size, how many solar panels you need, total system cost and estimated monthly payment.