The volume of a prism is the product of the area of the base and the distance between the two base faces, or the height (in the case of a non-right prism, note that this means the perpendicular distance).
In 2017, most homeowners are paying between $2.87 and $3.85 per watt to install solar, and the average gross cost of solar panels before tax credits is $16,800. Using the U.S, average for system size at 5 kW (5000 watts), solar panel cost will range from $10,045 to $13,475 (after tax credits). Thatâs nine percent lower than it was a year ago, and solar panel system costs are continuing to fall.
Fiberglass Roof Average Costs. 1  Fiberglass roof panels cost $2 to $4 per square foot installed. Assuming an average roof size of 1,500 square feet, that's a total cost of $3,000 to $6,000. 2  Fiberglass roof shingles cost $2.50 to $5 per square foot installed ($3,750 to $7,500).