We have all noticed solar panels on neighbouring rooftops, but many have dismissed them in the past as over expensive and offering minimal benefit. Things are changing, and we, as consumers, are becoming much more conscious of our environment, our carbon footprint and energy consumption – especially at a time of sky high energy prices.
Now is a great time to think about installing solar panels due to rising energy prices, with the UK electricity price per kWh set at a limit of 34p/kWh under Ofgem’s price cap, as from 1 October 2022 (for dual fuel customers paying by direct debit.)
How Do Solar Panels Work?
Photovoltaics (PV), also called solar electricity panels, capture solar energy from the sun and turn it into usable electricity. You can create renewable electricity by installing solar panels, and you could even get paid for it!
A solar PV panel is made up of numerous cells composed of layers of silicon or another semiconducting material. This material conducts electricity when exposed to light.
The cells can function even on cloudy days without direct sunlight. However, electricity production increases with sunshine intensity.
Each solar panel in a solar PV system produces about 355W of energy in conditions of intense sunlight. A typical system produces about ten panels of direct current (DC) electricity. An inverter is installed with the system to convert DC electricity to AC because household appliances use alternating current (AC). You can use this electricity inside your house or export it to the grid.
How Many Solar Panels Do I Need?
Calculating how many solar panels to power a house with the necessary electricity will guarantee that your solar system can produce enough power.
Your annual energy usage, which you can find on your electricity bill, is what you need to know to do that.
Based on a variety of factors, different properties will have varying numbers of solar panels:
- Size of Property
- Energy Usage
- Solar panel power output
You can calculate the number of solar panels you’ll need to install to meet your needs using the annual energy usage of your property.
The size of your household is one of the main factors in deciding how many solar panels you need for your solar system. As a rough guide, the following size solar panel systems are recommended:
| Number in household | Recommended solar system |
| 1-2 | 3kW |
| 3 | 4kW |
| 4 | 5kW |
| 5+ | 6kW |
The number of solar panels you require will depend on the output of your solar system and the size of the panels themselves.
As an example:
- 12 solar panels would be required to install a 3kW solar system with 250W panels.
- 24 solar panels would be needed for a 6kW system with 20W panels.
The specific number of solar panels required will depend on whether you want your solar system to meet your full household electricity requirements or just part of them.
How Do I Calculate the Size of the Solar System I Need?
You must first determine how much energy your system must produce to meet your household’s demand. Your daily energy consumption can be ascertained by looking at your monthly energy bills.
Your daily consumption, for instance, would be 3.75 kWh if your February consumption was 105 kWh in that month. This means that your solar system needs to have an expected daily power output of 3.75 kWh on average each day throughout that month.
How Big Are Solar Panels?
The average solar panel is around 1.65 metres (65 inches) by 1 metre (39 inches) and has 60 cells. If you are wondering how many solar panels can fit on your roof, then you should be able to work it out from this calculation if you know the square meterage of your roof.
Solar panels of this size are excellent for the typical home or residential property, but larger panels with about 72 solar cells are also available if you’re placing them on a business or commercial property. Inevitably, the greater the size of the solar panel, the larger the cost.
Your solar installer will be able to advise you on which solar panels are the most suitable for your particular situation.
What Size Solar Panels Do I Need?
You should be aware of the following information to determine the size of the panels required for your home:
- How much energy is produced by solar panels of various sizes
- How many square metres of space is available on your roof
- Solar panel dimensions by size or brand
Solar panels’ amount of energy varies depending on their wattage size or rating. For example, a 200 watt panel can produce up to 200 watts per hour of sunlight, while a 350 watt solar panel would be capable of producing up to 350 watts per hour. Because of this, figuring out how much energy you’ll need is crucial before deciding on the size of your solar panels.
The good news is you won’t have to worry about this, as one of our solar panel partners will be able to do all the calculations for you to ensure you get the right sized solar array.
What Type of Solar Panels Should I Choose?
When choosing a solar panel type, there are multiple factors to consider including your budget, the efficiency of the panels, and your available roof space. The number of solar panels you need will depend on their efficiency and ability to produce enough electricity to meet your needs.
You can choose from various solar panel types, but monocrystalline or polycrystalline solar panels are generally the most popular. Monocrystalline solar panels take up less space than other options such as thin-film and polycrystalline solar panels.
Monocrystalline
Monocrystalline solar panels are considered the most efficient, with efficiency rates between 15% and 20%. They are also capable of producing more energy per area than other solar panel types, making them a good space-efficient option.
A monocrystalline solar panel will produce around 10W more power than a polycrystalline solar panel of the same surface area. Their high efficiency and superior silicon used in production, make them a more expensive solar panel option.
Polycrystalline
Due to their greater tolerance to high-temperatures Polycrystalline solar panels produce more electricity annually than monocrystalline panels.
Polycrystalline solar panels are more affordable. However, they are not as efficient due to the less pure silicon used in the production process. With polycrystalline solar panels you can expect an average efficiency rate of around 13–17%.
How Much Do Solar Panels Cost?
Your budget will have a major bearing on the type of solar panels you choose and therefore your overall cost for a solar panel system. How many panels, plus the size and type, will all impact on cost, as will your choice of inverter and whether to go with battery storage.
To give you a general idea about solar panel costs, solar panel systems with capacities between 3 kW and 12 kW, range in price from around £5,995 to £13,500.
That said, there are other factors that can impact on cost and that includes regional differences in the cost of solar panels and labour. Additionally, there may be some particular issue with your property that might complicate the solar installation and lead to extra cost.
Is My Roof Suitable for Solar Panels?
Understanding how many solar panels you might need to power your house with cost-free, renewable solar energy is one thing, but your roof must be suitable for solar panels.
On the plus side, the majority of UK homes are ideal candidates for solar panels, but there are a few things to consider to maximise their effectiveness:
- A roof that faces south will generate the best energy production.
- A roof with little or no shade is more effective
- 30 to 40 degree roof pitch
- Whether there is sufficient room (a 4 kW system can take up around 28 square metres of space)
Energy Usage
It should go without saying that solar panels produce the majority of their energy during the day. The hours between 6 and 10 in the evening, however, when there is less sunlight, especially in the winter, are when we use the most electricity.
Therefore, if you work during the day and come home in the evening, you’ve missed the best times to use your solar PV system’s free renewable energy. A solar battery can be useful here.
What is a Solar Battery?
Your solar panels produce more energy during the day than is consumed, so solar batteries are used to store any extra.
You can lower your reliance on your energy provider in the evenings and even at night by doing.
Is Solar Battery Storage Required?
Installing solar battery storage as part of your overall solar panel package is the best choice if you want to maximise your benefits from residential solar panels. Solar storage can in some instances help you avoid having to pay electricity bills at all and minimise your reliance on the grid. However, installing solar panels without solar battery storage is still a viable option if your goal is to lower your energy costs rather than aim to be completely electricity self-sufficient.
There are numerous advantages to using solar battery storage.
- Store the excess electricity produced
- You will require less electricity from the grid.
- Your carbon footprint will be reduced.
- You pay less for electricity, or in some cases, none at all.
Solar households wiith battery storage use a much greater percentage (around 80%) of the energy they produce, compared to homes without battery storage (40%). Your savings will depend on several factors including the size of the solar array, the number of batteries installed and their storage capacity.
To maximise the amount of energy you produce and your savings, you would need to install more solar panels and batteries. One of our solar install experts can give you advice on the best solar options for your requirements.
What Are The Alternatives to Solar Panels?
More people can now receive help from free renewable solar energy thanks to advancements in solar technology. So, flexible solar panels and solar roof tiles are other options if you can’t fit enough conventional solar panels on your roof.
Flexible solar panels are much more flexible than conventional solar panels because they are much thinner and lighter. As a result, anyone living in a house with a roof that might not be able to support the weight of several solar panels need not discount renewable solar energy to lower their energy costs.
Solar roof tiles, also known as solar shingles, are often an attractive choice as part of a roof replacement. Even though they do tend to be a little more expensive than solar panels, their energy production is much lower, and they aren’t suitable for all types of roof.
