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Last updated: 9 April 2024

12kW Solar System in the UK: Costs, Batteries + Pros & Cons

12kW solar system hero
  • 12kW solar systems are often used by large 6+ bed houses
  • You will spend approximately £9,500 – £10,000 pounds on a 12kW solar system in the UK
  • In the UK, a 12kW solar system produces around 28–66kWh a day in average 4 sun hours.

Switching to solar power is a wise decision for homeowners who want to reduce their carbon footprint and save money. For growing households with high energy demands, a large 12kW solar system is absolutely needed. 

If a 12kW solar system fits your home requirements, you will need an installer you can trust. Yet finding an experienced professional on your own can drag on for days if done alone. A busy homeowner like you doesn't have that much precious free time to spare.

Fortunately, Household Quotes can help you skip frustrating searches. By filling out a 30-second form, you can receive up to 4 free solar panel quotes from local solar panel installers. Just compare the prices and rest assured – you have no hidden fees to pay and no obligation to place any orders. Click below to begin!

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12kW solar system with battery storage in the UK

In the UK, a 12kW solar system with battery storage has the capacity to generate 900–2,000kWh monthly or 10,200–24,000kWh annually. That's a lot of electricity and therefore, such a large system caters to 5-6 room households with 5+ occupants.

A photovoltaic solar panel is the essential type for generating electricity, distinct from solar thermal panels serving the purpose of providing hot water. The diagram below shows how solar panels for homes produce electricity.

12kW overview

A typical solar energy system requires:

  • Solar panels: Usually, a 12kW solar panel system in the UK requires 26 450W panels or 32 350W panels. How many panels you need depends on the capacity of the panels, your household size, and your energy requirements. 
  • Solar batteries: Usually you have to choose between a lead-acid battery or a lithium-ion one, and the capacity you need depends on your housing situation as well. 

How many solar panels are in a 12kW solar system?

A typical 12kW solar power system typically requires either 26 450W panels or 32 350W panels. But this number heavily depends on the specific wattage of the panels you choose. 

A general rule of thumb, the higher the efficiency of the panels, the fewer actual items you need. 

How many batteries are in a 12kW solar system?

The two most common solar battery storage system choices are lead-acid batteries and lithium-ion batteries. Lithium-ion batteries, like Tesla Powerwall and Powervault 3, are the most popular choice for residential installations in the UK.

Usually, a 12kW system goes with a lead-acid battery size of 60kWh–78kWh and a lithium-ion battery sized between 31kWh and 41kWh. 

When choosing a battery, you should opt for its capacity rather than number. The more storage you need, the more powerful your solar battery storage system should be. 

For an accurate estimate of which battery suits you best, it's highly advisable to consult an experienced solar installer. Apart from batteries, they can recommend the best solar panels in the UK based on your energy consumption patterns, local electricity rates, and your budget. 

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How much does a 12kW solar system cost in the UK?

The average cost of a 12kW solar system usually stretches between £15,000 - £17,000.

There are several factors that influence the cost of a 12kW solar system:

  • Battery size – a 12kW system usually suits large households with a high number of occupants, that's why a battery with higher capacity is preferred, and therefore it's more costly.
  • Solar panel types – Monocrystalline panels are typically more expensive than polycrystalline panels.
  • The installation costs – panels won't install themselves so account for labour fees and any other additional materials required for installation, like a mountain system.
12kW solar system cost overview
FactorPrice
Solar panels£15,000 - £17,000
Battery£9,500 – £10,000
12kW system plus battery£24,500–£27,000
Labour (per person per day)£300 – £500
Maintenance (for a panel)£4 – £15

To save up on the cost of solar panels, it's best if you compare quotes from various installers in your area or search whether you are eligible for any available grants or solar panel incentives.

How much power does a 12kW solar system produce?

Depending on the sunlight hours, a 12kW solar system in the UK produces around 30–66kWh per day, 900-2,000kWh of energy monthly which translates to an average of 10,200kWh per year.

How much power will a 12kW solar system produce?
Time periodEnergy produced (kWh)
Daily30–66 
Monthly900–2,000
Yearly10,200

The amount of power a 12kW solar system can produce heavily depends on the amount of sunlight it receives. 

To achieve the best result, make sure your roof faces south and the angle is typically around 30 to 45 degrees in the UK. This angle helps capture sunlight more effectively throughout the year, maximising the energy output of your 12kW system.

The amount of sunlight received in the UK varies depending on the region. Here's a breakdown of the average daily sunlight hours in the UK:

uk sunlight

For example, a 12kW system that receives 4 sunlight hours on average daily during the year, produces around 975kWh per month. 

If you think your household doesn't require this much electricity, you can switch to solar systems with lower capacities:

What is the break-even point and lifespan of a 12kW solar panel system?

On average, solar panels typically last for 25 to 30 years. Yet the solar panel size influences the break-even point greatly. 

Generally, you have to consider the cost of your 12kW solar system, the cost of electricity in your area, and the amount of sunlight in your area.

Let's say you install a 12kW solar panel system for £14,000. 

The average cost of electricity is 24.50p/kWh (Ofgem) and the system's annual production is 10,200 kWh. By multiplying the annual energy production by the energy costs we find out the annual savings, £2,856 for our situation. 

By dividing the system cost of £15,000 - £17,000 by the amount of annual savings we received, we get an approximate break-even point of 5 - 6 years.

So, there are approximate break-even periods for a 12kW solar panel system:

break-even

Yet these are just rough estimates and you should contact a professional for more tailored information. 

Are you already dreading the thought of spending your weekend searching for an installer instead of time out with friends? Indeed, googling the quotes and reading customer reviews might take hours of your time with no guarantee of successful finds. 

Household Quotes is here to help you avoid time-consuming browsing. Complete our 30-second form and receive up to 4 free quotes from trusted solar panel installers near you. Our service is free and non-binding – just compare the offered quotes with no pressure to place any orders. Click below to get hassle-free solar panel quotes.

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What are the advantages and disadvantages of 12kWh solar systems?

12kW pros and cons

Solar panel advantages and disadvantages can vary based on factors such as location, individual energy needs, or availability of local regulations. 

Advantages

  • Higher energy capacity: these systems typically offer a higher energy capacity, providing a substantial amount of electricity for residential or small commercial applications. 
  • Eco-friendly: solar energy is a clean and renewable source, contributing to a reduction in greenhouse gas emissions and environmental impact.
  • Energy independent: 12kW systems enable greater energy independence, reducing reliance on traditional grid power and potentially leading to long-term savings.
  • Smart Energy Guarantee: UK homeowners can enjoy incentives like SEG which provide financial benefits or compensation for surplus energy fed back into the grid.

While there's a list of benefits, large solar panel systems come with some drawbacks. 

Disadvantages

  • Costly investment: the initial cost of a 12kW system is between £15,000–£17,000 which poses a substantial investment. However, long-term savings on energy bills may offset this initial expense. 
  • Roof space: a 12kW solar system requires about 75m2 free roof space which can be a limitation for properties with limited or shared roof areas.
  • Battery storage: the additional cost of batteries can further increase the overall investment.

Is a 12kW solar system with batteries worth it for your UK household?

Are solar panels worth it in the UK? Determining whether a 12kW solar system with batteries is worth it depends on various factors and individual circumstances. There are several factors you should consider:

  1. Energy needs – since a 12kW system has a significantly high capacity, it's suitable for larger households with higher energy demands. So you should thoroughly consider your home's energy consumption.
  2. Roof space – consider the orientation and shading of your roof and ensure that your property has sufficient roof space.
  3. Cost vs Savings – consider the initial investment cost against long-term savings on electricity bills.
  4. Regulations and incentives – do your research on local regulations, permits, and any government incentives or feed-in tariffs that can offset costs.
  5. Lifespan – despite relatively low maintenance, the lifespan of the equipment and the manufacturer's warranty are quite long.

Get the best 12kW solar system for your UK household

12kW solar systems are an optimal solution for households with higher energy demands. Yet, the initial investment and roof requirements can be too costly for some homeowners. 

If you're still in doubt whether your home will benefit from a 12kW system, it's best if you seek professional advice. This way, you get a recommendation tailored to your particular housing situation and heating requirements.

Household Quotes can help you find your dream installer without monotonous searches. Simply complete our 30-second form and we'll provide you with 4 quotes from installers near you. Our service is free and non-binding. Click below to begin!

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