Watt Vs. Kilowatt: What’s the Difference?
By Madison LaBerge /
In this EcoWatch guide on 300 watt solar panels, you’ll learn:
This guide has helped thousands of homeowners save time and money when gong solar. Let’s get started!
Each product and or company featured here has been independently selected by the writer. You can learn more about our review methodology here. If you make a purchase using the links included, we may earn commission.
Most solar panels made for residential customers are larger than 300 watts, but there are plenty of manufacturers who make this size solar panels for RV solar installations, solar applications on boats, light residential use, and more. Below are our top-rated solar panels in the 300-watt size class.
Regional Service
Average cost
Pros
Cons
We like Blue Raven Solar because it understands that, for most homeowners, the cost of solar presents the biggest barrier to entry.
For that reason, Blue Raven Solar developed an innovative solar financing plan that offers in-house, flexible, zero-money-down options. The results speak for themselves, as Blue Raven Solar is now one of the fastest-growing solar companies in the nation and was recently acquired by SunPower. Its BluePower Plus+ plan (exclusive to Blue Raven) mimics the flexible structure of a lease while still providing the greatest benefits of owning your system.
Eligible homeowners enjoy 18 months of solar power before having to pay their first bill. When coupled with the federal solar investment tax credit (ITC), the initial energy savings can offset more than a third of the overall cost of a system before requiring a dollar down.
In contrast, other installers can only offer similar financing through solar leases, PPAs or third-party providers (such as Mosaic or Sunlight). Third-party loan providers can complicate the process, while opting for a loan or PPA will disqualify you from some of solar’s biggest benefits (additional property value, federal solar tax credit and local solar incentives).
EcoWatch Rating |
---|
Better Business Bureau (BBB) Rating |
Year Founded |
Average Cost ($-$$$$$) |
Solar Services |
Brands of Solar Equipment Offered |
Warranty Coverage |
4.5 |
A+ |
2014 |
$$ |
Solar Panels, System Monitoring |
Trina Solar, Canadian Solar, SolarEdge, Silfab, SunPower |
25-year manufacturer warranty; 10-year workmanship warranty, 2-year production guarantee |
Solar panels — even smaller ones that are meant for light use, like 300-watt panels — can quickly get expensive and push you over your budget. While renewable energy will generally save you money on electricity costs, in the long run, optimizing your panel selection to suit your budget will always be important.
The table below provides a side-by-side pricing comparison of the top five 300-watt solar panels available. Keep in mind that the prices reflected below are very likely not the total you’d pay for fitting home or even an RV with solar panels, as the production from a single panel would be far too low.
Solar Panel | Price Per Panel | Total Price |
Renogy RNG-300D 320-Watt Monocrystalline Panels | $399.99 | $1,599.99 (includes four panels) |
AIMS Power 330-W Solar Panels | $331.00 | $1,989.00 (includes six panels) |
Grape Solar 370-Watt Solar Panels | $405.66 | $1,217.00 (includes four panels) |
ACOPOWER 300W Mono Solar Panel RV Kit | $497.00 | $497.00 (includes 300W worth of panels and MPPT charge controller) |
DOKIO 300W Portable Solar Panel Kit | $299.00 | $299.00 (includes one foldable solar panel and solar charge controller) |
With the high prices, you’ll pay for solar panels, it’s important that you look for brands and solar module options that include warranty coverage.
Some smaller panels are rated to last for a decade or more, and the companies that stand behind their products will not only instill confidence when you’re shopping, but they’ll also protect you from having to replace your equipment shortly after buying it. Many companies include shorter warranties that cover your equipment for just a few years.
Unfortunately, many of the major solar manufacturers — like SunPower, Tesla, and Panasonic — no longer make 300-watt panels, as advancements in solar technology have led them to focus on higher-production panels largely for on-grid applications. These larger companies more often have lengthy warranties, so the coverage you’ll find for smaller panels will be limited in most cases.
The table below provides warranty information for the top five 300-watt solar panels we’ve mentioned above.
Solar Panel | Warranty Coverage Included |
Renogy RNG-300D 320-Watt Monocrystalline Panels | 10-year warranty for materials and workmanship |
AIMS Power 330-W Solar Panels | 25-year limited warranty |
Grape Solar 370-Watt Solar Panels | 10-year limited product warranty plus 10-year warranty for 90% output and 25-year warranty for 85% output |
ACOPOWER 300W Mono Solar RV Kit | 5-year workmanship warranty plus 25-year warranty for 85% output. The charge controller comes with 1-year limited warranty |
DOKIO 300W Portable Solar Panel Kit | 1-year warranty |
The size of your 300-watt solar panel will depend on the specific model and manufacturer, as the number of solar cells used and the size of those cells will affect the dimensions. That being said, the average size for a 300W solar panel is around 36 inches by 65 inches.
Panels created with DIY solar energy systems in mind tend to be made with aluminum frames and are kept at a lightweight for easy maneuverability. The table below includes dimensions for the top five brands we’ve mentioned above.
Solar Panel | Product Dimensions (Per Panel) | Panel Weight (Per Panel) |
Renogy RNG-300D 320-Watt Monocrystalline Panels | 39.4” by 65.6” at 1.4” thick | 9.93 lbs |
AIMS Power 330-W Solar Panels | 39.25” by 65.35” at 1.37” thick | 40 lbs |
Grape Solar GS-M60-US 300-Watt Solar Panels | 39.25” by 65” at 1.5“ thick | 10.75 lbs |
ACOPOWER 300W Mono Solar RV Kit | 26.4” by 40.2” at 1.4” thick | 12.78 lbs |
DOKIO 300W Portable Solar Panel Kit | 21” by 52” at 0.98” thick (unfolded) | 17 lbs |
It’s challenging to say with certainty how much energy a 300-watt solar panel will produce, as production can be influenced by many things. Factors to consider include the brand of the panel you have, the efficiency for which that brand is rated, the intensity of the sunlight hitting your panel, how many hours of sun your panel receives every day, the direction your panel faces, and more.
With that being said, you can use the calculation below to help you determine how much power your panels will produce:
Your Daily Watt-Hours per Panel = [average hours of sunlight] x [solar panel wattage] x [75% maximum power production to account for changing weather conditions and lower sun intensity in the morning and afternoon]
Your Daily Kilowatt-Hours (kWh) per Panel = [your daily watt-hours] / 1,000
If you assume you average around six hours of sunlight per day, your calculation would be as follows:
[6 hours of sunlight] x [300 watts] x 75% = 1,350 watts per day
[1,350 watts per day] / 1,000 = 1.35 kWh per day
If your area experiences the same average sunlight year-round, one 300-watt solar panel could produce around 492.75 kWh per year. This calculation can often be used to determine how many panels you’ll need in total for your solar project, which we’ll discuss in greater depth further down.
A single 300-watt solar panel can be used to run quite a few different small appliances and electronics (and even so much as an EV charging station).1 The table below provides a list of some of the most common household items homeowners run using a 300-watt solar panel.
Appliance/Household Item | Running or Rated Watts Required to Run |
Ceiling Fan | 60 watts |
Vacuum Cleaner | 200 watts |
PC (Non-Gaming) | 240 watts |
Small Dehumidifier | 250 watts |
Rice Cooker | 200 watts |
Heated Blanket | 200 watts |
TV | 230 watts |
Crockpot | 250 watts |
DVD Player | 100 watts |
Laptop Charger | 125 watts |
Projector | 280 watts |
Phone Charger | 10 watts |
Mini-Fridge | 100 watts |
Gaming Console | 180 watts |
Hair Straightener | 120 watts |
Electric Can Opener | 170 watts |
Home Speaker System | 100 watts |
Paper Shredder | 225 watts |
Watch Below: See how this person is using a single 300w solar panel to power his camper van.
Above, we mentioned that it’s challenging to determine the expected power output for your solar panels, even if you know the wattage and voltage. Solar power systems rely on available sunlight for power generation, so changes in the availability of sunlight — which occur frequently throughout the day — will have an impact on your rate of production.
Solar system voltage — including open-circuit voltage (VOC) and short circuit current (ISC) — is important, although it’s an often-overlooked measurement when it comes to solar equipment. When discussing voltage, it’s often easiest to think of a water tank with a pipe connected to the bottom. The higher the water tank and the more water is contained within it, the faster the water will travel down and out of the pipe. Voltage works similarly, and your panels won’t charge your batteries or power your devices if your voltage is too low.
For example, many solar panels have a voltage of between 15 and 18 volts per panel. This is high enough to charge a 12-volt battery bank or supply power for something that uses 12 volts. Solar panels can be set up in series — often using branch connectors — to provide higher voltages for running multiple electronics at once — like in the case of a residential solar panel system — or to charge larger, higher-voltage batteries — like solar batteries or other power banks that run at 24 volts or more.
Solar panel voltage can be affected by wave length and distance to the sun.2
You can determine the number of solar panels you need by calculating how many kilowatt-hours (kWh) your home uses each year and dividing by the estimated production of each panel.
For example, a single 300-watt solar panel in an area that receives six hours of sunlight each day will produce approximately 492.75 kWh per year. If you can calculate how much energy you consume annually, you can divide by this number to determine how many 300-watt panels you need.
According to the U.S. Energy Information Administration (EIA), the average home in the U.S. consumed 10,572 kWh in 2024.1 If you planned on using Renogy 300-watt panels to power your home, for example, you could use the below calculation to figure out how many panels you’d need for a 10kW solar system:
(10,572 kWh used annually) / (492.75 kWh produced per 300-watt panel) = 21.45, or 22 panels
Keep in mind that this calculation assumes that your property receives six hours of sunlight per day and that your home uses the average amount of electricity. Your numbers could vary, so it’s best to calculate using numbers that accurately reflect your home energy consumption and climate.
At 22 panels required, 300-watt panels aren’t used for homes as often as larger ones. The best panels for homes are generally rated for higher production, meaning you’ll need fewer panels on your roof to maintain the required level of energy production.
The cost information presented in this article is derived from a comprehensive analysis, incorporating data from multiple industry sources. The average cost per watt per state was calculated based on figures from Consumer Affairs, Energy Sage, and Berkeley Lab’s Electricity Markets & Policy Department. Additionally, monthly energy consumption and the average monthly cost of electricity were sourced from the U.S. Energy Information Administration, ensuring a well-rounded and accurate representation of the information presented.
A single 300-watt solar panel generates enough electricity to run most common household appliances. If your home consumes the national average of 10,572 kWh per year, you would need at least 22 300-watt solar panels to power your entire household under sunny conditions.
Most homeowners opt for solar panels with 400 watts or more of power if they want to generate enough electricity for their entire home.
A single 300-watt solar panel will generate enough electricity to power most small appliances or a small fridge. However, to power a full-size or large fridge, you will need additional solar panels. Of course, if you want continuous power to keep your refrigerator running throughout the night, you’d also need a solar battery.
Of the brands we evaluated, a single 300-watt solar panel costs between $299 and $500.
Comparing authorized solar partners
Having trouble deciding? Click below and use our process to receive multiple quotes instead: