For panels rated at 340W, pricing may range from $0. 20 per watt. This fluctuation can be attributed to various aspects, including brand reputation, durability, and efficiency ratings. . 340W panels hit the efficiency sweet spot – With 18-21% efficiency ratings, 340W panels offer optimal balance between power output and cost, making them ideal for most residential installations where roof space isn't severely limited. Federal tax credit uncertainty creates urgency – The 30% federal. . A 340 solar panel can be installed with the help of mounting brackets or mounting frames. 340 watt solar panel price depends on several factors: manufacturer, quality, warranties, efficiency of a module. Chinese brands tend to lower the solar panel 340 watt price, but Europeans, Americans, Japanese. . The average expense for a 340W solar module can range significantly, typically between $0. 20 per watt, which translates to around $272 to $408 per panel. Installation costs can vary, often falling between $1. 50 per watt depending on the complexity of the setup, location, and. . Most homeowners spend between $12,600 and $33,376 to install a complete residential solar system in 2025, with the national average at $19,873 before incentives. is between $15,000 and $25,000 before incentives. The total price depends. . Solar panel installation costs a national average of $18,180 for a 6kW solar panel system for a 1,500 square ft. 50 and largely depends on the home's geographical area. Residential solar panels are usually sized between 3 kW and 8. .