400W Solar Panel Modules (Guide)

Our guide to 400w solar panels includes: 

Daily Electricity Production

Daily electricity production for a 400w solar panel module is likely to be in the range of 0.8kWh to 1.2kWh. 

This is a very loose estimate. To get an accurate estimate of what system you need or how much electricity your solar panels are likely produce daily:

• Use our solar panel tool here
• Contact our solar energy experts here

At around 1kWh per day, expect a monthly production of approximately 30kWh. This is a far cry from the 2,700kWh-4,100kWh annually that an average household might consume.

To achieve somewhere close to partiy, the average household is going to need a 4kW-5kW solar panel system.  For this, you’d need around 12 x 430w panels. 

As an example of the type of system you’ll need, this is the most popular setup we install: 

A range of variables affect a solar panels output and production including: 

Daylight hours

Solar panels only produce electricity during daylight hours. And the amount of daylight hours varies depending on where in the UK you're based as well as the time of year (there are less daylight hours in winter than summer). 

Roof Pitch & Orientation

An optimum roof setup would be a 30 degree pitch, and facing due south. Anything other than this would produce suboptimal electricity production. 

Solar Panel Efficiency

The efficiency rating of your solar panels has a big impact on daily production. 

Low quality panels can be sub 20% efficiency, whereas a high quality 400w solar panel module from the likes of LONGi (such as the Hi-Mo X6 Guardian) would operate at 23% or higher.

How Many 400W Solar Panels Do You Need?

In order to achieve a reasonable level of electricity generation the average household is going to need 10-15 x 400w solar panels. 

The most popular system we install is a 5.16kW setup, which incorporates 12 x 430w panels.

It’s worth noting that this system uses high efficiency LONGi solar panels. These panels operate at over 23% efficiency, which is much higher than the average panel. 

If you choose to install a cheaper and less efficient solar panel, you’ll need more panels to match the overall energy production of LONGi’s 430w modules.

The Cost of A Solar Panel System

A solar panel system suitable for a 2-4 bedroom property using panels that are 400w or higher, is likely to cost around £6,000 through dwellow. 

This price doesn’t include a solar storage battery…

Read more about prices in our guide to the cost of installing solar panels here…

The big decision you'll need to make isn't whether you choose 400w solar panels or bigger, or even how many you need; our solar panel configuration tool can quickly suggest the most suitable setup.

Instead, it's whether or not you choose to install a solar storage battery, or not.

If you don't have a solar storage battery, you'll have 2 options: 

• Let any excess electricity production go to waste
• Hook up to the grid and sell excess electricity via the Smart Export Guarantee (only to buy it back later at a higher price)

That's why the majority of the systems we install include a small 5kW solar storage battery (as a minimum). 

Costs, including installation, for solar storage batteries from dwellow are: 

• Small 5kW battery: £2,495
• Medium 10kW battery: £3,745
• Large 15kW battery: £4,995

Solar batteries allow you to make the most out of the electricity your system produces. 

To see how different battery sizes affect self-sufficiency ratings and energy bill savings, use our solar panel tool here.

And if you're still not sure if you need a solar battery, speak to our solar panel experts here. 

Top Brands Producing 400W Solar Panels

There are dozens of brands producing 400w solar panels. You’ll want to pick the brand with the best balance of efficiency, price and warranty. 

As an example, the LONGi Hi-Mo 6 is mid-range in terms of price, yet considered a premium product in terms of both warranty and efficiency.

You’ll get in excess of 23% efficiency from the Hi-Mo X6 Guardian. And it comes inclusive of a 25-year performance guarantee. 

LONGi's warranty is better than most. The 25-year guarantee covers a maximum 1.5% degradation rate in year 1 and a maximum 0.4% degradation rate from years 2-25. 

Ultimately, that means you'll still have a solar panel that's 88.90% efficient, even after 25-years!

Here is a list of the best solar panels for efficiency: 

Read more about why LONGi solar panels are our most popular offering here. 

Or, get your system spec’d with prices on-screen, using our solar panel quote tool.

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