How To Choose the Right Size Solar System

Once you have decided that your house is suitable for solar, you will need to figure out what size system to install.

Some factors to consider are:

  • Roof sizeFirst, you’ll need to find out how many panels you can fit on your roof.

    Solar installers can help you with this over the phone by using mapping websites or Google Earth, which allows them to accurately measure your roof. From there, you can get quotes for sizes up to the maximum allowable. Be aware that you can only use sections of your roof between east, south and west. not north facing roofs.

    Keep in mind that the smaller systems can have panels facing in only one direction (across multiple sections of the roof is ok) whereas larger systems, over 3kW, can have panels facing in two different directions and across multiple sections (this is a feature of better quality inverters that use Maximum Power Point Tracking or MPPT).

    Let us organise for an installer for you and they can figure out exactly how many panels you can fit on your roof. They’ll also be able to give you a price range, for a few different size options.

    If you’re not sure about all of this, you’re probably best organising for a few installers to get in touch so that they can give you a proper appraisal. If you’d like a quote, we can organise this for you here.

  • BudgetThe average cost of solar is between £3,000 and £6,000 depending on the size of your roof.

    Although this may seem expensive initially it is a long-term investment and you will make this money back through Government incentives and reduced electricity bills.

    Prices vary depending on quality and size and below is a rough guide of potential out-of-pocket expenses.

    The following out of pocket prices ranges are correct as of July 2017 and assume 250W panels as a standard:

    System size Number of panels Price range Estimated first year return
    1.5kW approx 6 £2,500 – £3,500 £196
    3kW approx 12 £4,000 – £5,000 £542
    4kW approx 16 £5,000 – £6,000 £708
    5kW approx 8 £6,000 – £8,000 £376


  • Household usageGenerally speaking, the bigger the household usage, the more benefit you’ll get from choosing a larger size system. Keep in mind any anticipated growth of your family or when your kids will enter their teenage years, as they will start consuming more electricity the older they get.

How to work out the best system size?

Once a solar installer gets in touch, they’ll look at a few of your previous bills and figure out how many units (kWh) you use on average per day. From there, they’ll ask you a few questions about your lifestyle and your family size to work out what percentage of that daily usage you use during the daytime.

Once they’ve figured this out they’ll suggest a system that will produce a similar amount to this or one that produces slightly more depending on anticipated growth in usage or how much power usage you can shift into the middle of the day such as washing machines and dishwashers.

From there, they’ll recommend a few sizes with different quality components depending on your budget.

Important: We recommend you get a few different quotes so that you can tell if their numbers are overly optimistic.

Getting a Solar Power Quote from a MCS certified installer in your local area is easier than ever.

Proceed to get a quote now!

Fatal error: Call to a member function toArray() on array in /data/sites/ on line 4

Fatal error: Call to a member function replace() on null in /data/sites/ on line 123