How Many Solar Panels Do I Need For 1000 kWh Per Month?
To generate 1,000 kWh per month, you would need approximately 35–36 high-efficiency 400W solar panels.
Whether you’re in Southern England, South West England, or South Wales, sizing your solar system correctly ensures you meet your energy needs while maximising savings.
This guide breaks down the calculations for the number of solar panels needed to generate 1000 kWh a month, the factors affecting panel count, and key considerations to help you make an informed decision.
How Many Solar Panels Are Needed to Generate 1000 kWh Per Month?
To generate 1,000 kWh per month, you would need approximately 35–36 high-efficiency 400W solar panels.
For most homeowners and landlords, a 14 kW system with 35–36 high-efficiency 400W panels is ideal, producing around 12,000 kWh annually to meet this demand, based on UK sunlight conditions. Factors like roof orientation, shading, and seasonal variations may adjust this number, so consult a professional like EE Renewables for a tailored assessment.
The average UK household consumes around 2,900 kWh per year, meaning 1000 kWh per month is significantly higher, typical for larger homes, families with electric vehicles (EVs), or small businesses.
How to Calculate the Number of Solar Panels Needed to Produce 1000 kWh Per Month
In the UK, a 1 kW solar system generates approximately 850 kWh per year due to the country’s average sunlight hours (750–1,100 kWh/m² annually, per the Energy Saving Trust). To calculate the system size:
- Annual energy requirement: 1000 kWh/month × 12 = 12,000 kWh/year.
- System size needed: 12,000 kWh ÷ 850 kWh/kW = 14.12 kW.
- Panel count: Assuming high-efficiency 400W panels (common in 2025), divide 14,120 W by 400 W/panel = 35–36 panels.
Here’s a breakdown for different panel wattages:
| Panel Wattage (W) | Approx. Annual Output per Panel (kWh) | Panels Needed for 12,000 kWh/year |
|---|---|---|
| 350 W | 298 kWh | 40–41 panels |
| 400 W | 340 kWh | 35–36 panels |
| 450 W | 383 kWh | 31–32 panels |
For precise sizing, consult a professional installer like EE Renewables, who can assess your property’s specific conditions.
What Factors Influence the Number of Solar Panels Needed?
Several variables affect how many solar panels you’ll need to achieve 1000 kWh per month. Understanding these ensures your system is neither under- nor over-sized.
Roof Orientation and Tilt
- Optimal placement: South-facing roofs at a 30–40° pitch maximise solar output in the UK, per the Energy Saving Trust.
- East/West-facing roofs: These produce 10–20% less energy, requiring 2–4 additional panels.
- North-facing roofs: Avoid if possible, as output can drop by 30–40%.
Shading and Obstructions
- Shading from trees, chimneys, or buildings can reduce output by up to 50%. Microinverters can mitigate this by allowing each panel to operate independently.
- A site survey by an installer like EE Renewables can identify shading issues.
Seasonal Variations
- Summer vs. Winter: Solar output drops by ~50% in winter due to shorter days and lower sun angles.
- To cover 1000 kWh/month year-round, you may need a larger system or a battery to store excess summer energy.
Panel Efficiency
- Higher-efficiency panels (e.g., monocrystalline, 20–24% efficiency) produce more electricity per square metre, reducing the number of panels needed.
- Lower-efficiency polycrystalline panels may require 2–3 additional panels for the same output.
How Much Roof Space Is Required for 1000 kWh Per Month?
A 14 kW system requires significant roof space, which is a key consideration for homeowners and landlords in areas like Bristol or Southampton.
- Panel size: A standard 400W panel occupies ~1.7 m².
- Total roof space: 35 panels × 1.7 m² = ~59.5 m².
- Additional space: Allow 10–20% extra for mounting and access, totaling ~65–70 m².
| System Size (kW) | Approx. Panels (400W) | Roof Space Needed (m²) |
|---|---|---|
| 12 kW | 30 | 51–60 m² |
| 14 kW | 35 | 59.5–70 m² |
| 16 kW | 40 | 68–80 m² |
For smaller roofs, consider high-efficiency panels or explore ground-mounted options if your property allows.
What Are the Costs and ROI for a 1000 kWh Per Month Solar System?
Investing in a solar system to produce 1000 kWh per month involves upfront costs but offers significant long-term savings, especially with rising energy prices.
Installation Costs
- Average cost: A 14 kW system costs £16,000–£20,000, including panels, inverter, and labour.
- Additional components:
- Battery storage: £7,000–£10,000 to store excess energy.
- Microinverters: £1,000–£2,000 for shading-heavy roofs.
- 0% VAT: Until 2027, solar installations in England, Scotland, and Wales benefit from 0% VAT, saving up to £3,000.
Return on Investment (ROI)
- Annual savings: A 14 kW system generating 12,000 kWh/year could save £2,500–£3,000 at 25.8p/kWh (July 2025 Price Cap, Ofgem).
- Smart Export Guarantee (SEG): Export excess energy at 6–30p/kWh, earning £300–£900/year .
- Payback period: 6–8 years, with panels lasting 25–30 years, per Solar Energy UK.
| System Size (kW) | Cost | Annual Savings | Payback Period (Years) |
|---|---|---|---|
| 12 kW | £14,000–£17,000 | £2,200–£2,700 | 6–8 |
| 14 kW | £16,000–£20,000 | £2,500–£3,000 | 6–8 |
| 16 kW | £18,000–£22,000 | £2,800–£3,300 | 6–8 |
For a tailored cost estimate, request a free quote from EE Renewables, serving Southern England, Greater London, South West England, and South Wales.
Is My Property Suitable for a 1000 kWh Per Month Solar System?
Installation feasibility depends on your property’s characteristics, especially for high-energy users like EV owners or small businesses in Cardiff or Oxford.
Roof Strength and Condition
- Roofs must support ~15–20 kg/m² for panels and mounting. Older roofs may need reinforcement, adding £1,000–£3,000 to costs.
- If your roof needs replacing, consider installing solar simultaneously to save on labour, per the Federation of Master Builders.
Planning Permission
- Most domestic installations fall under Permitted Development rights, but Listed Buildings or Conservation Areas require permission.
- Landlords must obtain tenant or council approval for installations.
High-Energy Appliances
Households or businesses using 1000 kWh/month often power energy-intensive appliances. Solar can offset costs for:
- Electric vehicles (EVs): Charging an EV can add hundreds of kWh per month, and powering it with solar can substantially reduce running costs. Using solar to charge an electric car is a practical way to increase energy independence.
- Hot tubs: Maintaining water temperature in a hot tub requires consistent energy, which solar panels can supply efficiently, reducing your electricity bills. Read our guide on how many solar panels you would need to run a hot tub if you have one.
- Swimming pools: Heating and circulating pool water is energy-intensive, and pairing solar panels with pool systems can cover a large part of this demand.
- Other household appliances: Large fridges, freezers, kitchen appliances, and other high-power devices can also benefit from solar power. Understanding which appliances can be powered by solar helps in sizing your system correctly.
How Can I Maximise Solar Output for 1000 kWh Per Month?
To ensure your system meets your energy goals, consider these strategies:
- Use high-efficiency panels: Monocrystalline panels (20–24% efficiency) reduce the number of panels needed.
- Install a battery: Store excess summer energy for winter use, increasing self-consumption and savings.
- Optimise energy use: Shift high-energy tasks (e.g., EV charging) to daylight hours when panels generate the most power.
- Regular maintenance: Clean panels annually to maintain efficiency, as dust can reduce output by 5–10%.
For expert advice on maximising output, contact EE Renewables for a bespoke residential or commercial solar system design tailored to your property.
FAQs
Can I add more panels later to meet 1000 kWh/month?
Yes, you can add additional panels to your existing solar system, but it’s costlier due to additional labour and inverter upgrades. It’s better to size your system correctly upfront. Consult EE Renewables for a scalable design.
Do solar panels work in cloudy UK weather?
Yes, panels generate electricity even on cloudy days, though output is reduced by 20–50%. A 14 kW system accounts for this to meet 1000 kWh/month.
How does a smart meter help with a 1000 kWh/month system?
A smart meter tracks energy production and export for SEG payments, maximising earnings from surplus energy.
Are there grants for a 1000 kWh/month solar system?
The ECO4 scheme may cover costs for low-income households or low-EPC homes.
What’s the lifespan of a 14 kW solar system?
Quality panels last 25–30 years, with inverters needing replacement after 10–15 years.
Our Verdict
Sizing a solar system to generate 1000 kWh per month requires careful planning, considering your roof’s orientation, space, and energy habits. A 14 kW system with 35–36 high-efficiency panels is typically needed, costing £16,000–£20,000 but offering £2,500–£3,000 in annual savings and a 6–8 year payback.
By addressing shading, optimising panel placement, and exploring battery storage, you can maximise efficiency and ROI.
For homeowners, landlords, or small businesses in Southern England, Greater London, South West England, or South Wales, EE Renewables offers expert guidance and tailored solutions. Request your free quote today to start your solar journey.
