Pros / These panels require little maintenance since they can be cleaned with just water.

Cons / The company is young, which might be a concern for some consumers.

 Verdict / The Grape 390W solar panels are durable, offer good solar efficiency and plenty of wattage.

This solar panel company is relatively new on the scene, but certainly has made its mark in both the United States and Canadian markets with reasonably priced solar modules for home as well as commercial use. The company is based in Eugene, Oregon, and it offers solar panels that are primarily made in China or other Asian countries and then assembled in the U.S. However, you can request solar modules that are manufactured completely in the U.S. if you prefer.

Since its inception in 2009, Grape has built a network of installers for its products, and the company also sells directly to consumers. It has pushed sales energetically throughout the U.S. and Canada and created partnerships with such firms as Costco and Home Depot.

The Grape Solar 390W panels provide a solar efficiency percentage of 15.21 percent, which is good in the solar panel industry. The module cells are monocrystalline and the frame is made of anodized aluminum. The cover is tempered glass.

With this panel, you get a maximum power output of 390 watts, a maximum power voltage of 49.4 volts and a top power current of 7.92 amps. These modules are constructed to hold 95 individual cells.

You get a solid warranty with the Grape Solar 390W modules. The company offers a 10-year warranty on materials and workmanship. There also is a 10-year warranty covering power output that states you will receive 90 percent of the power you were assured of receiving when you originally bought the panels. Additionally, there's a 25-year warranty that states you will get 80 percent of the power output you were originally promised.

These solar panels can handle temperature ranges of 40 degrees below zero to 194 degrees F. The Grape Solar 390W panels can take on hailstones that are approximately one inch in diameter traveling at terminal velocity, and they can withstand a two-inch steel ball weighing nearly 19 ounces dropped on it from a distance of slightly more than four feet. They also can handle a maximum load of snow at 50 pounds per square foot.

Theses solar modules can take on brisk temperatures of 40 degrees F. below zero, which is standard in the industry. They also can handle blistering weather that produces rooftop temperatures up to 194 degrees F. The cover materials are made of tempered glass and the frame is made of anodized aluminum.

Each Grape Solar 390W module measures 77.2 inches long, 51.5 inches wide and 1.57 inches deep. Each weighs 78.2 pounds. These solar panels can be cleaned with just water.

Grape Solar makes an effort to be available to consumers and is proud of its Oregon headquarters and the English-speaking workers in the U.S. and Canada. If you have questions about the product, you can consult the frequently asked questions section on its website. You also can contact the company either through email or by calling the firm Monday through Friday from 8 a.m. to 5 p.m. Pacific Standard Time. The level of customer service you get by phone is first-rate, with helpful and well-informed representatives available to answer your calls. You also have access to a customer hotline to contact the firm’s technical support team if you have an extremely pressing question.

  • Solar Efficiency
  • Time to Recoup Investment
  • Warranty
  • Max. Power Wattage
  • Max. Power Voltage
  • Max. Power Current
  • Panel Cells
  1. The amount of electricity a panel converts from sunlight per surface area.
    More is Better
  2. 3  Grape Solar 390W
    15.21 Percentage
  3. 16.0 Percentage
  4. 15.9 Percentage
  5. Category Average
    15.29 Percentage


Although fairly new in the solar world compared to a number of other companies – it was launched in 2009 – Grape Solar has built a North American network of installers who sell its products and consumers who buy them. Despite the company's relative youth, it produces solar panels that are durable and efficient, and you'll get excellent customer service if you ever need to contact the manufacturers.

Specifications and Benchmarks


Minimum Temperature
Maximum Temperature
Cover Materials
Tempered Glass
Frame Materials
Anodized Aluminum


Warranty Product & Workmanship
Warranty Power at 95-97% (Years)
Not Specified
Warranty Power At/Above 87% (Years)
Not Specified
Warranty Power at 90% (Years)
Warranty Power at 80% (Years)
Maximum Load Capacity (Pounds Per Square Foot)
Impact Resistance (Hail at Wind MPH)

Solar Efficiency

Solar Efficiency (percentage)
Maximum Power (Watts)
Maximum Power Voltage (Volts)
Maximum Power Current (Amps)
Cell Technology Type
Number of Cells

Overall Cost & Benefit Comparison

Average Total Cost
Time to Recoup Investment (Years)

Help & Support


Cost Comparison Details

Cost Per Panel
Number of Panels for Sample Homes
Total Panel Costs
California Home Scenario
Panels + Installation Cost
Total Federal Tax Credit
California State Rebate
Total Estimated Cost After Credits
Monthly Electric Bill Savings
Wisconsin Home Scenario
Panels + Installation Cost
Total Federal Tax Credit
Wisconsin State Rebate
Total Estimated Cost After Credits
Monthly Electric Bill Savings


Length (Inches)
Width (Inches)
Depth (Inches)
Weight (Pounds)