How Many Solar Panels to Power a House?

Are you considering photovoltaic (PV) solar panels for your roof? Not sure how many Solar Panels it will take to power your House? Solar energy…
How Many Solar Panels to Power a House?

Are you considering photovoltaic (PV) solar panels for your roof? Not sure how many Solar Panels it will take to power your House? Solar energy is an unbeatable source of clean, renewable energy but how many panels would you actually need? This article sets out some simple calculations you can make to work this out.

The case for clean energy

Even before the recent warning about a surge in energy prices, homeowners were experiencing year on year increases. Many chose to Invest in PV solar panels (which convert the sun’s rays into electricity). Not only could they reduce their bills by reducing their reliance on the National Grid but some could earn money by feeding power back into the system.

Today, the case for installing PV panels is even greater, especially given the greater efficiency of modern solar panels. This means that you will need fewer panels on your roof to generate the same amount of energy as before. Or looking at it from the other angle, you will be able to generate more energy then ever by maximising your roof’s solar panel coverage.

The following calculations will help you work out exactly how many solar panels you will need to generate a specific amount of energy.

Calculating how many solar panels you need to power your home

The number of solar panels you need to power your home will depend on whether your goal is to partly or completely offset your expected energy consumption and whether or not you want to generate extra energy to be sold back to the grid under the Smart Export Guarantee scheme.

If you want to match the amount of electricity you are currently drawing, you need to get hold of your latest electricity bill and work out how much that is. Every electricity bill, by law, has to tell you how much energy you are consuming in kWh (kilowatt hours), even if this is based on estimated readings. Ideally, you should add up a years’ worth of bills to calculate your annual energy usage. You can then divide this by 365 days to arrive at your daily electricity usage.

Alternatively, you could find a recent monthly or quarterly bill and divide the figure by 30 or 90 respectively. Bear in mind though that summer bills are likely to be lower than average due to extra lighting and indoor activity in the winter.

Next, you need to calculate the daily power output from the solar panels you intend to install. Cisco Homes Ltd. are not tied to a specific supplier so we can help you to source the panels you want.

Each panel will come with a daily power figure, usually provided in watt hours. On average, the UK gets between 4 and 5 hours of sunlight per day (this obviously varies month by month). If you multiply 4.5 by the output value of your panels and divide by 1,000, you will arrive at a rough figure for daily kWh generation.

E.g. 4.5h x 330W = 1,485 Wh = 1.485 kWh

By dividing the first figure you calculated (your daily home consumption) by the second (daily solar panel generation) and rounding up to the next number, you will know how many panels you will need to meet your needs.

If your home consumes the average household usage of 10.221 kWh, you would therefore need 10.222 / 1.485 = 6.9 or 7 solar panels of this power installed on your roof.

Request a free solar survey

Cisco Homes Ltd. can help you to work out precisely how many solar panels it will take to power your house and how you can manage your energy generation using the latest inverter and battery storage technologies. Visit our dedicated solar installation page and book your free solar survey today.

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