400w solar panels

400-watt solar panels: What you need to know

When comparing solar panel options, one important metric to consider is a panel’s power rating, referred to as wattage. 400-watt (W) solar panels are above the average wattage of solar panels available today and can be a solid panel option for many types of solar projects.

Most solar panels installed on homes or businesses today are between 250 to 365 watts per panel, and solar panels above and below that range are also available. In order to determine if 400W solar panels are right for you, it is important to understand what the options are and how much energy 400W panels produce.

What are 400W solar panels?

A 400W solar panel produces an output of 400 watts of electricity, and it can be used for both commercial and residential solar projects. 400W solar panels will produce approximately 1.2 and 3 kilowatt hours (kWh) daily, of course depending on their exposure to sunlight and other factors including geographic location and tilt.

How much do 400-watt solar panels cost?

Because of their larger size and output, 400W solar panels tend to be 5-10%  more expensive than their smaller counterparts. They are generally more expensive overall, and more expensive in terms of cost per watt. This is because the technology used to produce this type of panel is still relatively new. However, their larger size means that you won’t have to install as many of this size panel compared to smaller panels.

Uses for 400-watt solar panels

400W solar panels are some of the largest panels on the market and are still relatively uncommon for use in residential applications. Most residential solar systems use 300W solar panels. However, there are still many uses for consumers to try 400W panels.

400-watt solar panels for boats and RVs

Although they are still not widely used for residential homes. 400W panels are well-suited for powering RVs, boats and other devices with off-the-grid use. In fact, a single 400W panel would be able to power an RV or boat for a significant amount of time.

List of 400W solar panels

Not many companies manufacture truly 400W solar panels. Below is a selection of solar panels that produce close to 400W of power, each listed with their efficiency and the company that makes them.

List of ~400-watt solar panels

ManufacturerPanel modelWattage (W)Panel efficiency (%)
Hanwha Q CELLSQ.PEAK DUO L-G5.2 38038018.9
Hanwha Q CELLSQ.PEAK DUO L-G5.2 38538519.1
Hanwha Q CELLSQ.PEAK DUO L-G5.2 39039019.4

How many 400-watt solar panels do you need?

The number of solar panels you’ll install depends on the amount of electricity you want to generate and the space available for solar panels.  Many people choose to go with the 400W solar panel due to a lack of roof space; this is because 400W solar panels produce electricity more efficiently than many lower-wattage solar panels given the space they take up. The table below compares different sized solar panel systems by the number of 400W solar panels needed for each system size. In some cases, the number of 400W panels is rounded to the nearest panel.

How many 400-watt solar panels do you need? System size comparison table

System size (kW)Number of 400-watt solar panelsEstimated space needed (sq. ft.)
2 kW5114
5 kW13296
6 kW15341
7 kW18410
*Number of panels rounded to the nearest panel, and space needed rounded to the nearest foot

Using five 400W solar panels will produce roughly 3,000 kilowatts hours (kWh) of electricity, which is significantly below the amount of electricity a typical single-family household uses. Installing 15 panels for a roughly 6 kW system will produce enough electricity to significantly offset or eliminate your electric bill with solar.

How much space will a solar energy system using 400W panels take on your roof or property?

The table below demonstrates estimates for solar energy systems using only 400W solar panels. For the purpose of calculating estimated space needed, we assumed that 400W solar panels are, on average, 22.75 square feet (6.5’ by 3.5’).

System size (kW)Average annual kWh productionNumber of 400W solar panels (rounded)
2 kW2,8205
5 kW7,05013
6 kW8,46015
7 kW9,87018
*Number of panels needed rounded to the nearest panel, and assumes a production ration of 1.41

Solar panels close to 400W are relatively efficient with the space they use when compared to lower wattage panels, and a standard roof of a single-family home will likely have enough space for the number of panels needed to significantly offset electricity costs. If you have a small roof or even a roof you don’t want to be covered in panels, consider a ground-mounted solar system.

Are 400-watt solar panels right for your solar installation?

400W solar panels are above the average wattage of panels used for most solar installations but still will make sense for some property owners. While they may be more expensive per panel than lower wattage options, 400W panels make up for the price premium in the space they save on your roof and the lower number of panels you will need to purchase to cover your electricity needs.

Whether you’re looking for low, standard, or high wattage panels, you can get multiple solar quotes from pre-screened installers by signing up on the EnergySage Solar Marketplace. If you have preferences when it comes to solar equipment, you can simply note them in your account so installers can quote accordingly. If you’d prefer to start investigating your solar options with a quick estimate on what solar can save you, try our Solar Calculator.

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About Jacob Marsh

Jacob is a researcher and content writer at EnergySage, where he's an expert on current issues–and new technology!–in the solar industry. With a background in environmental and geological science, Jacob brings an analytical perspective and passion for conservation to help solar shoppers make the right energy choices for their wallet and the environment. Outside of EnergySage, you can find him playing Ultimate Frisbee or learning a new, obscure board game.

7 thoughts on “400-watt solar panels: What you need to know

  1. Thomas D Morgan

    We have two paralleled MPP Solar LV5048’S. Each one has room for 4000watts of pv power into PV1 and PV2 inputs for a total of 8kw.
    Looking for recommendations on a monocrystaline panel (400w) to install on a ground mount that is controlled by a dual axis tracker.
    Thanks in advance, Tom

  2. Noel Banda

    Am looking for a 400 watts solar panel,i need to know the rest of the kit that i need to buy eg inventer,battery etc.Your response will be greatly appreciated.Thanks.

  3. Dan

    I’m glad we are now edging the 350-400 wt panels. At this rate, within 5-7 years 500w panels will be the standard. If price per wt comes down to usd $.35 solar will finally take off. We will see if the US will lag behind such revolution, as it has most of the decade due to Big Power lobbying against solar panels made overseas or we will see if the US becomes a leader, as China has.

  4. Spencer

    I have a 500W unit that I’ve evaluated for the last three years made in Korea. Naurally anyone could understand why PVT units are a better option for thermal and electricity generation, more or less solar Micro CHP that can be adopted for air conditioning or solar chillers, dish and machine washing rather than centralised solar concentration plants unless these can be scaled down using evacuated tubed scale constructions for more efficient concentration. We can see that’s far of from the local hardware store for years to come. These are all areas for exploration especially in areas of temperate climates. Solar is a investment after all, something to keep for years if not decades to come.


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