The number of solar panels you can fit on a roof depends on several factors. Installers must consider the size of the solar panels, the condition of your roof, and its area of useable space.
Installers must also ensure the installation isn’t too small for your energy requirements or too large for your property. But with careful consideration, planning and expert calculations, it’s more than possible to obtain a solar system that’s perfectly tailored to your needs.
How many solar panels do I need to power my home?
Before working out how large a solar system you need, ask yourself the following questions:
- How big is your home? Do you live in a flat or detached house?
- Do you work from home?
- How many people live in your home?
- Is your home well-insulated?
- Do you use electricity or gas, too?
While this may seem like a lot, each of these questions will directly relate to your home’s general power consumption.
Be thorough and look through your electricity bills for the last year. If you’re not in the habit of keeping your electricity bills, start now. You can put together a bigger picture of your energy consumption if you have data from different points in the year.
Can I power my house using only solar power?
Without significant financial investments, it is unlikely that you’ll be able to power your home using 100% renewable energy. It’s more likely you’ll use a combination of green and grid-generated power.
There are three main factors to consider when determining how much solar power is necessary to support your current consumption.
What is your typical energy consumption?
The more electricity you use, the more solar panels you’ll need.
According to Ofgem, the average UK household uses 2,700 kWh of electricity per year. You can use this figure to determine your energy usage, but it may not be entirely accurate.
In the UK, sunlight levels fluctuate on a seasonal and even regional basis. So, for a more personalised look into your energy consumption, consider using a solar panel calculator.
This three-stage calculation will look at your most-used appliances, their wattage and how many hours you use them per day. You can even go more in-depth and discover your energy consumption on a monthly basis (according to peak sunlight hours).
Does your home get enough sunlight?
In winter, countries in the Northern Hemisphere lean away from the sun. UV rays hit the Earth’s surface at an angle and make the sun appear lower in the sky; this can affect energy generation in a number of ways.
With fewer daylight hours, solar productivity may alter in winter. However, the positives certainly outweigh the negatives! In the spring, summer and early autumn, your home is exposed to direct, more concentrated sunlight for longer periods of time.
By using The Met Office’s UK climate averages, you can see how many hours of sunlight you’re going to receive at different points in the year.
Looking at these figures in conjunction with your yearly energy requirements may give you a better idea of how many solar panels you’ll need.
| Month | Average peak sun hours per day |
|---|---|
| January | 2 hours |
| February | 3 hours |
| March | 4 hours |
| April | 6 hours |
| May | 6 hours |
| June | 7 hours |
| July | 7 hours |
| August | 6 hours |
| September | 5 hours |
| October | 4 hours |
| November | 3 hours |
| December | 2 hours |
What are the conditions of your roof?
Realistically, you can’t get your required number of solar panels without a roof to support them.
If you’ve got high energy needs (and, therefore, require a larger solar system), your roof needs to be structurally sound enough to support the weight. You’ll also need enough room for installation.
Sometimes, architectural features like roof windows or skylights may decrease your roof’s total available surface area. Other parts of the roof may be unusable due to constant shade.
You can attempt to calculate your roof’s total available surface area yourself by multiplying the length of your roof by the slope height. You would then need to multiply this by two and account for any obstructed areas.
Or, you can contact the experts at Project Solar to assess this for you.
How to calculate how many solar panels will fit on your roof
As you can see, determining how many solar panels will fit on your roof isn’t a straightforward process.
Even once you’ve worked out how many panels you’ll need (based on your average energy consumption), you’ll still need to think about the size of the panels themselves.
What is the size of a solar panel?
Solar panels vary in size from manufacturer to manufacturer, so giving an average is next to impossible! However, it’s true that as solar panel technology has advanced, PV systems have become more compact.
To find out the size of your manufacturer’s solar panels, you’ll need to get in touch with them directly.
What is the maximum number of solar panels allowed in the UK?
In the UK, there is no specified maximum number of solar panels that can be installed on a roof. However, there are some regulatory considerations to keep in mind.
To install solar panel systems of a certain size, you must obtain prior approval from the local Distribution Network Operator (DNO). Doing so ensures that the local grid can handle the additional load that the solar system may feed back into it during peak generation times.
Join the solar takeover!
Learning more about your energy consumption can have a great impact on your life. You’ll not only have a better understanding of the most suitable solar system for you, but it can also make you a more mindful consumer.
Join our journey towards the net-zero 2050 goal by going green! With more residential and commercial installations, we can reduce our collective carbon footprint. To learn more about what we offer, get in touch.