guide

Home solar panels: how much sunlight does it take to power a home?

27 May 2021 | Aimee Tweedale

So you’ve read all about solar panels and how they work, and you’re thinking about getting some installed. What next?

Shopping around for solar panels for your home can be overwhelming. There are a lot of different options and sizes, and you might not be sure how much electricity you actually need to generate. 

Solar panels on a house

That’s why we’ve put together this guide, to help you work out whether it’s possible to power your whole home with sunlight, and exactly how many panels you’ll need. Time to get out the calculator!

Can I run my entire house on solar power?

Whether or not you can power your entire home with solar energy will depend on a few different factors. Here are the 3 most important questions you’ll need to answer first:

  • How much electricity do you generally use?
  • How much sunlight does your home get?
  • How much space do you have for solar panels on your roof?

The first question will tell you how much power you need to run your home. The answer to the second question will tell you how much solar power you’re likely to generate. And the final answer will help you figure out whether you can fit enough panels on your roof to power the whole house. 

Already know how much electricity your home needs in Watts? In that case, you can use this helpful solar power calculator from the Solar Centre UK to work out how many panels you’re likely to need for your house. 

How much solar energy do I need to power my house?

Everybody’s answer to this question will be different. How much electricity you normally use can depend on lots of things – like:

  • How big the house is
  • How many people live there
  • Whether you use gas, or just electricity
  • Whether you work from home
  • How well-insulated your house is

To find out how much electricity you use at home, check your last 12 months of electricity bills. Remember, you’re likely to use a lot more energy in winter months than summer, so check as many bills as you can, to get a full picture of your average use. 

The best way of knowing exactly how much energy you use at home is to install a smart meter. These clever meters tell you exactly how much power you’re using via your In-Home Display, so you’ll never have to make an educated guess. They also make sure the amount shown on your bills is always accurate. 

Find out how to get a smart meter installed at home for free

How much electricity does the average UK household use?

Looking for some quick figures, so you can work out if solar is worth it for you? 

The average home in the UK uses about 3,731 kWh of electricity per year. That figure comes from the Department of Business, Energy & Industrial Strategy. If you live in a flat, your energy use is likely to be smaller. Likewise, if you live in a detached house, it’s likely to be higher.

Ofgem, the energy regulator, also publishes Typical Domestic Consumption Values (or TDCVs) every 2 years. TDCVs reflect the average household energy use in the UK according to current trends. Energy companies use TDCVs to work out quotes for new customers, so that when you’re shopping around, you can see like-for-like comparisons.

According to the TDCVs, a ‘medium’ home uses 2,900kWh of electricity per year. For those in Electricity Profile Class 2 (that means you’re on an Economy 7 tariff), that’s 4,200 per year. Find out more about TDCVs for different size homes.

Wondering what on earth a kWh is? Check out our complete guide to kWs and kWhs

Solar panels in the countryside

Do I have enough sun for solar power?

Contrary to what you might think from looking at our grey skies, here in the UK we do have enough sunlight for solar power!

The Met Office has worked out these average figures, to give you an idea of how much sunlight we get year-round in the UK1.

MonthAverage peak sun hours per day
January2 hours
February3 hours
March4 hours
April6 hours
May6 hours
June7 hours
July7 hours
August6 hours
September5 hours
October4 hours
November3 hours
December2 hours

Find more specific climate averages for your area by visiting the Met Office website

If you’d like to find out how much sun your house gets specifically, you could buy a solar radiation meter. These are also sometimes called irradiance meters, and they can help you decide if solar power is right for you. Find more specific climate averages for your area by visiting the Met Office website.

Do solar panels need direct sunlight to work?

Not necessarily! Solar panels can produce power even on cloudy days. In fact, even if it’s snowing or hailing, as long as there’s some light, your solar panels can generate electricity!

That being said, it’s true that your solar panels will reach maximum efficiency during peak sunshine hours. 

There are ways to make your solar panels even more effective. You should install them on a south-facing roof, where they’ll catch the most rays. (We wouldn’t recommend installing solar panels on a north-facing roof.) It’s also best to install them at a 30-40 degree angle. 

Read up on everything you need to know about installing a solar PV system at home

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How many solar panels do I need?

So, now you know how much electricity you need, and how much sun you’re likely to get. The final question remains: how many panels will you need to power your home, and do you have space for them?

To answer this, we need to look at how much energy solar panels can generate. Most home panels can each produce between 250 and 400 Watts per hour. 

According to the Renewable Energy Hub, domestic solar panel systems usually range in size from around to 1 kW to 5 kW. Allowing for some cloudier days, and some lost power, a 5 kW system can generally produce around 4,500 kWh per year.

As we saw above, the average UK home uses around 3,731 kWh per year. So a 5 kW system, or possibly a 4 kW system, would probably do the trick. 

A 3.5 kW system usually needs about 12 panels2, and a 4 kW system might need 14 or 15. You’ll need to measure your (south-facing!) roof to work out whether you can fit 14-15 panels up there. 

To make the most of solar electricity when the sun isn’t shining, it’s worth thinking about installing a home energy storage system, too. This will hold on to the power generated during sunny hours, so you can keep living off-grid all year round. 

Read more about batteries, and other home energy storage solutions

Woman watching TV at home

Uses of solar energy: how much solar energy does it take to…

Boil a kettle?

Boiling a kettle for your cuppa uses a bit more energy than you think. In fact, kettles are estimated to eat up about 6% of the UK’s electricity3!

Each time you hit ‘boil’, you’re likely to use about 0.15 kWh of electricity4. If you’ve got a 1 kW solar panel system on your roof, then it could power your cup of tea with about 10 minutes of sunlight. 

Read up on how to save energy in the kitchen

Watch a movie?

Let’s say you want to watch a 3-hour movie (Titanic, anyone?) on a 200 W TV. You’ll need about 0.6 kWh of electricity. 

Your 1 kW solar PV system could generate that in about 36 minutes. 

Run your fridge-freezer for a month?

This is an important one, because your fridge-freezer is one of the few appliances you have to keep switched on permanently. But how much sunshine would you need to keep it running?

Let’s say your fridge-freezer is an efficient model, with an A+++ energy-efficiency rating. It probably uses about 17.2 kWh a month5. It would take your 1 kW solar PV system a little over 17 hours of direct sunlight to power it. 

If you’ve got an A-rated fridge-freezer, you might need more like 34 hours of sunlight. 

In April or May, that would take 3 to 7 days of sunlight, for a month’s worth of electricity. Not bad for a small system!

Of course, if you upgraded to a 4 kW system, it would take less time. You’d only need about 5 hours of sunlight to keep your A+++ fridge-freezer cool all month long. 

Find out more about energy-efficient fridge-freezers in our practical guide

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Choose OVO to power your sustainable home

Want to make a real difference to the carbon footprint of your home?

Here at OVO, we supply all our members with 100% renewable electricity6, and we plant a tree for every year that you’re with us7

And if you want to go even further, we offer a green upgrade, OVO Beyond: it gives you 100% carbon-neutral energy8, and we’ll plant 5 extra pollution-busting trees for you each year9.

Find out more about how we’re powering homes around the UK with renewables, and get a quote in under 2 minutes, to see how much you could save by switching to OVO.

Sources and references:

1 https://www.theecoexperts.co.uk/solar-panels/how-many-do-i-need

2 https://www.renewableenergyhub.co.uk/main/solar-panels/how-much-electricity-does-a-solar-panel-produce/

3 https://www.theguardian.com/money/2019/feb/09/energy-bills-are-your-cuppas-costing-more-than-you-thought

4 https://www.bbc.co.uk/blogs/davidgregory/2010/09/boiling_a_kettle_with_solar_po.html

5 https://www.confused.com/gas-electricity/guides/appliances-how-much-do-yours-cost-to-run

6 The renewable electricity we sell is backed by renewable certificates (Renewable Energy Guarantee of Origin certificates (REGOs)). See here for details on REGO certificates and how these work.  

7 Each year, OVO plants 1 tree for every member in partnership with the Woodland Trust. Trees absorb carbon dioxide from the atmosphere, so tree-planting helps to slow down climate change.

8 Enjoy even greener energy with OVO Beyond in comparison with our standard OVO plans. In addition to 100% renewable electricity as available with our standard plans, OVO Beyond reduces your yearly carbon emissions from the energy used in your home that is supplied by OVO to net zero by providing 100% carbon-neutral gas (15% green gas and 85% offset) and offsetting all associated lifecycle carbon emissions involved in the production and consumption of your electricity & gas, you will also get 5 trees per year in UK schools and communities and other green benefits. The renewable electricity we sell is backed by renewable certificates (Renewable Energy Guarantee of Origin certificates (REGOs)). See here for details on Renewable Energy Guarantee of Origin certificates and how these work. A proportion of the electricity we sell is also purchased directly from renewable generators in the UK. The green gas we sell is backed via renewable certificates (Renewable Gas Guarantees of Origin (RGGOs)). See here for details on Renewable Gas Guarantees of Origin and how these work. We offset the remaining emissions by supporting UN REDD+ carbon reduction projects that are certified to the Verified Carbon Standard or the Gold Standard. See here for more information on how we restore nature and protect rainforests with our offsetting programmes.

9 OVO plants 5 trees for every OVO Beyond member through our  award-winning I Dig Trees programme with The Conservation Volunteers. Trees absorb carbon dioxide from the atmosphere, so tree-planting helps to slow down climate change. Since 2015 we have planted over 1 million trees.

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