What Size Solar System Does My Business Need?

Oliver Creevy

Ollie Creevy is a seasoned author with 5+ years of experience in writing home improvement content, focusing in particular on renewable energy, ECO grants and solar panels. His expertise has been featured on MSN, MIC, Bustle, and other platforms. As an author at Business Solar UK, he remains at the forefront of promoting cleaner, more efficient energy solutions for a brighter and more sustainable world.

Getting your solar system size right is probably the most important decision you can make as a business owner who is switching to solar. Get it wrong, and you’ll end up with a solar array that’s too powerful or too weak to cover your business energy needs. The problem is, the best way to find out what size solar system your business needs is with a review from expert installers. However, knowing what factors affect the solar system size you need is important in giving you a better understanding of what to expect. 

Below we’ll explore the different factors necessary to answer the question ‘what size solar system does my business need’, and then we’ll provide you with some common examples to give you a better idea of what you might expect for your business.

What Will Determine Your Business’ Solar System Size?

There are a few different factors that will directly influence the solar system size that’s right for your business:

  • Your business annual energy usage
  • The amount of daylight your panels will be exposed to
  • The size of the panels vs the size of your roof
  • Your budget

Annual Energy Usage

Your business annual energy usage is probably the most important factor determining the size of your solar array, because if you’re hoping to have solar cover all of your energy needs then you’ll need to know how much energy you use first and then find a system size that suits. 

Finding out your business energy usage is easy enough. You ought to have an annual energy bill summary that will show you your energy usage for the past year. If you don’t, you can always use your monthly energy bills and simply add up the total each month to find out how much energy in kWh your business has used in a year. 

Daylight Hours

The amount of sunlight you’ll receive throughout the day will vary depending on where you are in the UK. It won’t impact your solar system massively, but it could mean that a business solar installation in the north of the UK would need a panel or two extra than an installation in the south to achieve exactly the same energy output. 

You can find out how many daylight hours you can expect throughout the year in your location with a quick search online, but the solar installers we put you in touch with will also calculate this for you when helping design the perfect solar system for your business. 

Panel Size vs Roof Size

It doesn’t matter what size system you need based on your annual usage if your roof simply isn’t large enough to accommodate the number of panels in the solar system you’re considering. And remember, you won’t be working with your whole roof either.

North facing roofs are a no-go for solar panels because their efficiency is so severely affected. On the flip-side, south facing roofs are optimal for solar panels, and it’s here where you’ll get the most out of your new array. You can still use panels on east and west facing roofs, but you’ll want the majority of your system to be south facing if possible.

You’ll need to measure your usable roof space to determine how many panels you can realistically fit there. Most solar panels are around 2 metres x 1 metre, so you’ll need to allow for 2 square metres per panel on your roof. 

This is a good way for you to know the maximum solar system size for your business, and then work back from there.

Your Budget

And, of course, another important factor is your budget. Working out you need a 250kW system is all well and good, but if you don’t have £200,000+ to spend on it, then it isn’t worth considering. 

It’s probably a good idea for you to sit down and think about how much you’re willing to spend before comparing commercial solar installers with Business Solar UK.

Be Willing To Compromise

Balancing all of these factors is no easy feat. Which is why sometimes you have to be willing to make compromises to find the perfect solar solution for your business. You might have to accept that 100% of your energy needs won’t be covered by solar sources. 

But that’s not necessarily the end of the world. You can still make significant savings on your business energy bills with a solar system that doesn’t cover your full business energy usage. In fact, if your solar system covers only a small portion of your energy usage, you’ll still be making savings. 

It may be that you’d benefit most from a 110kW solar panel system, but a 50kW system is more appropriate for your roof space and budget. You’ll still be able to cover nearly 50% of your business’ energy with this setup, saving you significant money, and allowing you to make the most of your budget and roof space. 

Solar System Size And Their Uses

Below are some common solar system sizes for businesses and which businesses they are most appropriate for. HOWEVER, you should note that although some office buildings will be best suited to a 50.1kW system, not all office buildings will. The best solar system size is the one that’s right for your specific business, with your specific business energy needs, in your specific location. 

To help give you an idea about what’s common, here are some key solar system size examples:

System SizeNumber of 545W PanelsIdeal ForPrices From…
50.1 kW92 Office buildings£45,000
110.1 kW202Warehouse buildings£96,300
250.7 kW460Manufacturing plants£212,500
501.4 kW920Distribution centres£418,600

When you compare commercial solar installers with us, you might find that some of our installers are able to help provide you with a slightly more bespoke commercial solar package to help get the perfect system for you. The above table should be used as a guide only.

What Size Solar System Does My Business Need: Conclusion

Today’s guide should be seen as exactly that – a guide. The best way to know what size solar system is right for you is to talk with an expert about your needs and determine which solar system will serve you best. 

You can, however, use our guide today to help you get a rough idea about the sort of system size you might require for your business. Find out how much usable space you have on the roof of your business, work out your annual usage, look at your budget, and try to determine which system might be right for you. 

That way, you can enter the conversation with your commercial solar installer with some idea about what you could spend, and what size system you could need. Of course, this may change, but to have a general idea is always helpful. 

Compare commercial solar installers with Business Solar UK today, and then work with your chosen installer to find the perfect solar system for your business. 

Oliver Creevy

Ollie Creevy is a seasoned author with 5+ years of experience in writing home improvement content, focusing in particular on renewable energy, ECO grants and solar panels. His expertise has been featured on MSN, MIC, Bustle, and other platforms. As an author at Business Solar UK, he remains at the forefront of promoting cleaner, more efficient energy solutions for a brighter and more sustainable world.

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