How Many Solar Panels for a 4 Bed House?

If you’re a homeowner with a 4-bedroom property and you’re considering solar panels, one of the first questions you’ll likely ask is: how many panels do I actually need?

When weighing up a solar panel system, getting the right number of panels for your 4-bed home is critical. This decision directly impacts your installation costs, system efficiency, and ultimately, your return on investment.

For larger homes, such as those with four bedrooms and more, this decision becomes more significant due to higher energy demands and potentially more complex energy usage patterns. 

Our guide aims to provide you with all the essential information you need when it comes to adding solar panels to a 4-bed house. We’ll explore factors such as energy consumption, how to calculate your solar needs and considerations specific to larger homes. 

How much energy does a 4 bed house use?

According to Ofgem, the UK’s energy regulator, a 4+ bedroom house with 4 to 5 people living there consumes approximately 4,100 kWh of electricity annually. For your home, this figure should be taken with a large pinch of salt. That’s because it’s based on ‘4+’ bedrooms, which is a very broad range. 

Your actual usage will differ depending on a number of factors, such as:

• Number of people – Perhaps the biggest factor is the number of people living in the house. A household with two adults and two young children will typically use less energy than one with two adults and three older children.
• Home insulation – The quality of your home’s insulation plays a large role in energy efficiency. Well-insulated properties require significantly less power for maintaining comfortable temperatures year-round.
• Appliance efficiency – The age and energy ratings of your household appliances can make a substantial difference. Modern, energy-efficient models often consume far less electricity than their older counterparts.
• Heating system type – Your choice of heating system greatly impacts electricity usage. Homes relying on electric heating, such as heat pumps or electric boilers, use more electricity compared to those with gas central heating.
• Work and lifestyle patterns – Your daily routines significantly affect energy consumption. Families with members working from home generally use more electricity during the day than those who are out at work or school.
• High-power devices – The presence of energy-intensive equipment like tumble dryers and electric vehicle chargers can considerably increase your overall electricity usage.

The average annual consumption of 4,100 kWh for a 4-bed house provides a useful reference point, your actual energy usage is likely to vary. That’s why reviewing your own electricity bills is crucial when planning a solar installation. Your energy supplier can provide your annual consumption figure, offering a precise basis for calculating your solar panel requirements.

Using your current annual electricity use

When it comes to sizing a solar panel system for your 4-bedroom home, nothing surpasses the accuracy of your own electricity usage records. Whilst averages can provide a starting point, your personal consumption data offers invaluable insights. The benefits of using your own data are clear:

• Accuracy – Your energy bills gives you a precise picture of your household’s unique consumption patterns, capturing details that generalised estimates often miss. Whether you’re a family of early risers, work from home or are out all day, your annual usage data will account for these over the year.
• Year-round perspective – A full year’s worth of data takes into account both the peaks of winter and the troughs of summer in terms of the UK’s significant seasonal variations in energy use.
• Change indicators – Reviewing a year’s data can reveal gradual shifts in your energy needs, such as those caused by a new family member, a change in work arrangements or the addition of energy-efficient appliances.

To get your hands on this data, all you have to do is review your electricity bills from the past year or reach out to your energy supplier. With most providers, you can now download your usage history. 

Calculating solar panels needed for a 4 bedroom house

By now you should have a good understanding of your energy usage. Now it’s time to work out how many solar PV panels you need to install to cover your electricity needs. 

Let’s go through a practical example to show how many panels a typical 4-bed house might require assuming an annual electricity use of 4,100kWh per year. 

1. Annual energy consumption: 4,100 kWh
2. Daily energy needs: 4,100 kWh ÷ 365 days = 11.23kWh per day
3. Account for UK solar conditions: Using an average production ratio of 3.225 Wh per day per Watt of panel capacity, and considering 85% efficiency: 3.225Wh x 0.85 = 2.74Wh.
4. Calculate required system size: 11.23 kWh / 2.74Wh = 4.1kW (rounded up to 4.5kW for optimal performance and future-proofing)
5. Determine panel quantity: 4,500W / 370W = 12.16 panels, rounded up to 13 panels

In this example, you’d need 13 panels at 370W each to cover 4,100kWh across the year. You can input your own annual energy consumption, panel efficiency and (if this differs from 85%) and panel capacity to get a more accurate panel number estimation. 

It’s worth noting that your solar panels won’t produce the same amount of energy every day. In summer, they’ll likely exceed this average, whilst in winter, they’ll fall short. The goal is to size your system so that it produces enough energy over the course of a year to meet your annual needs. Many installers might recommend a slightly larger system – something like 5kW – to account for factors like potential increases in your future energy use. 

Solar setups for 4 bed houses

For a standard 4-bedroom property, solar systems usually range from 4-6kW. In terms of panels, you’re looking at:

• 11-14 x 370W panels
• 10-12 x 400W 

The area needed for these setups varies, but generally you’ll require about 30-40 square metres of roof space. Your exact requirements will depend on your roof’s shape and any potential shading issues.

Remember, these figures are guidelines. Your ideal setup may differ based on factors like:

• Energy efficiency – A highly efficient 4-bed home might only need a 4kW system 
• Additional power needs – Homes with electric heating or EVs might require 6kW or more 
• Roof orientation – South-facing roofs at a 30-40 degree angle are ideal, but non-south facing roofs may need extra panels for optimal output
• Location in the UK – Solar levels can change quite significantly across the UK. For example, the south of England receives an average of 4+ peak sunlight hours per day across the year. Northern Ireland however receives more like 3 hours of peak sun per day. This stacks up over the year.

Do you need battery storage for a 4 bed house

When they’re firing at their peak, a 4-5kW solar system can generate a significant amount of energy in a day. With four or five hours of good sun, you’re talking 20kWh and more of electricity. Given an average daily usage of 11.23kW for a 4 bed home, there will be plenty of energy left over that you can’t immediately use. 

You have two options here: send the electricity to the grid and get a small amount of money in return or store this spare energy in a storage battery to use later on. Our choice would be battery storage. 

For a 5kW solar system, a battery capacity of 5-7kWh often provides a good balance. On a sunny day, it’s highly likely that you’ll fully charge your battery when no one’s home without a problem. With a 7kWh battery, you then have all of this ‘free’ energy to use during the evening, overnight and in the morning if there’s any left before the sun starts shining again. Read up on the many more benefits of solar battery storage plus our guide to how battery storage works. 

To help you get the right size battery, it’s important to use your previous energy consumption patterns. This will help make you choose an appropriately sized battery that maximises your benefits without unnecessary expense. 

Prices for a residential storage battery range from £3,000 to £5,000. Whilst this adds to your initial investment, it can significantly enhance your system’s overall efficiency and value. It’s thought that a battery will help to increase your solar energy use by up to 80%. 

Some homeowners opt to start with just solar panels and add battery storage later, spreading out the investment. This approach allows you to understand your energy production and consumption patterns before deciding on battery capacity, but it will add to your costs compared to getting it all installed in one go. 

The impact of homes going all electric

In order to decarbonise our homes, we’re going to have to get rid of gas and oil and go electric. This electrification trend is good for carbon emissions but it will significantly impact your energy consumption and, by extension, your solar needs. 

Some key areas to consider include:

• EV adoption – With the ban on new petrol and diesel cars looming (it was 2030 but pushed back to 2035 under the Sunak government), EV ownership is set to rocket. Home charging an EV can add 2,000-4,000 kWh to your annual electricity use.
• Heat pump installation – These super efficient heating systems are gaining traction but can increase electricity consumption by 4,000-5,000 kWh yearly.
• Kitchen electrification – Switching from gas cookers and ovens to electric will bump up your electricity usage, albeit less dramatically than EVs or heat pumps.
• Electric water heating – Transitioning from a gas boiler to an electric system will noticeably impact your electricity needs.

When planning your solar setup, it’s crucial to consider these potential future changes. A system that’s perfect for your current needs might fall short if you electrify your home later. It is possible to add capacity to solar installations, but by factoring in these possibilities now, you can avoid costly upgrades down the line.

Costs and savings of solar panels for a 4 bed home

Using the industry guideline of £1,800 per kW, a 5kW system would cost around £9,000. This price should include everything such as the panels, inverter, brackets and installation. However, the final cost can vary based on factors such as system size, panel quality and installation complexity.

The investment in solar panels can lead to significant annual savings. A well-designed 5kW system has the potential to reduce your electricity bills by 60-80%. For a home consuming 4,100 kWh annually, this could translate to savings of £600-£800 per year, based on average UK electricity rates. It’s worth noting that as energy prices continue to rise, these savings are likely to increase over time.

Most homeowners find that their solar panel systems pay for themselves within 8-12 years. This payback period can be shorter if electricity prices rise or if you take advantage of schemes like the Smart Export Guarantee. To calculate the payback period, simply divide the initial cost by the annual savings.

Looking at the long-term benefits, over the typical 25-year lifespan of solar panels (which is often the warranty period), your total savings could amount to £15,000-£20,000 or more. This makes solar panels a sound long-term investment for many homeowners.

Alongside our information, it’s crucial that you consult with a qualified solar installer who will provide the most accurate assessment for your specific situation. They can evaluate your roof, analyse your energy needs and recommend a system that offers the best balance of cost, performance and future-proofing.