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What are Solar PV Panels?

Nick Geary
By: Nick Geary
Updated: 6th July 2022

What are solar PV panels?

Solar PV panels turn solar energy into free renewable electricity for your home.

So while they're not a heating system they can be used to power an electric heating system such as an electric boiler or heat pump. Which means you could be heating your home for free during the day.

What are solar PV panels?

Solar PV panels turn solar energy into usable electricity.

They work during the day – even when it's cloudy – and have zero running costs. The only time they won't be working is once the sun's gone down. But if you still want to power your home with free renewable energy during the night then you can add a solar battery to your system.

Visit our sister site Solar Guide to learn more about solar batteries.

How solar PV panels work

Solar PV panels are made up of photovoltaic cells (or solar cells) which hold electrons. When solar energy (which contains photons) hits the solar cells, these electrons move around – giving us an electrical current.

This is a direct current (DC) but we need an alternating current (AC) to use it around the home. So it needs to be converted. And this is the job of the solar inverter.

Once the current has passed through the inverter, it reaches a transformer. Here, the voltage is increased to 230v – the standard in the UK. The electricity can then be used around the home.

Advantages of solar PV

The list of benefits that come with installing solar panels is almost as long as your arm. Here are a few:

  • You could lower your electricity bills by as much as 50-60%
  • They don't cost a penny to run
  • You'll be able to power an electric heating system with free electricity
  • The electricity could also be used to power an electric vehicle
  • They won't need replacing for 20-30 years
  • Need very little maintenance over the years
  • You could earn payments through the Smart Export Guarantee

Plus, if you add a solar battery into the mix and you'll be powering your home for free into the night.

Interested in solar PV panels? You can get free quotes over at Solar Guide.

Is solar PV different from solar thermal?

There's a big difference between solar PV and solar thermal.

Rather than making electricity, solar thermal panels absorb heat from the sun that can be used to heat the water in a cylinder. There are no running costs whatsoever and solar thermal heating can provide a home with 40-70% of its hot water.

So while they're not a complete heating system, solar thermal can reduce your boiler's workload or immersion heater. Which can make a big dent in your bills.

Find out if solar thermal is right for your home.

Interested in Solar Thermal Heating?



Get the best of both with solar PVT

Solar PVT panels are a PV system with a thermal panel. This thermal panel not only helps to keep the PV panels cool but also warms up the water in the hot water cylinder. So you're getting the best of both worlds – electricity and hot water.

Solar PV for home heating

If you have an electric heating system then you can power it with free renewable electricity from your solar PV panels. This would give you free heating or hot water at certain times of the day.

Some electric heating systems include:

  • Electric boilers
  • Heat pumps
  • Immersion heaters

Electric boiler

Electric boilers turn electricity into heat. So if it's powered by renewable energy from your very own solar panels then you could be heating your home for free.

Smaller homes and flats with up to 10 radiators are the best places for an electric boiler. They'll struggle to meet demand in larger homes.

Heat pump

Heat pumps can reach efficiencies of 300-400%. To put that into perspective, condensing gas boilers have an efficiency of around 93%. But that doesn't hide the fact that they need a lot of electricity.

There are two types of heat pump: air source and ground source. Air source heat pumps take heat from the air outside while ground source heat pumps extract underground heat.

Immersion heater

Immersion heaters warm up the water within a hot water cylinder using electricity. So by pairing an immersion heater with solar panels, you could get free hot water.

Adding an immersion heater to your cylinder can take some of the workload off your boiler and make sure you still have hot water if your boiler breaks down.

If you have a combi boiler then you won't have a hot water cylinder. They're only fitted alongside system and regular boilers.

Find out more about how solar panels can power an immersion to give you free hot water.

How much you could save

A solar PV system could save you hundreds of pounds on your heating bills each year.

While electricity rates go up and down depending on the supplier and tariff, the typical standard rate in the UK sits at 16.36p per kilowatt-hour (kWh)*. That's around four times more than the price of natural gas (4.17p/kWh) – the most common fuel for home heating in the UK.

Most domestic electric heating systems have output ratings between 3 kW and 22 kW. Higher demand for heating will need a bigger output rating.

So to heat your home for an hour with a 3 kW electric boiler, for example, it will cost around 49p (16.36 x 3). The higher the output rating, the more it will cost to run.

Below, we've looked at how much it can cost to run various electric heating systems for an hour, week, month and year.

But before you get too carried away with possible savings, the solar panels won't be making electricity 24 hours a day. And other electrical appliances will be using the electricity too.

Electric boiler

A 3 kW electric boiler is only suitable for small flats with 2 radiators while the more powerful 15 kW can meet the heating demands of a home with 10 radiators.

Electric boiler output Running cost per hour Weekly running costs (2 hours a day) Monthly running costs (2 hours a day for 28 days) Yearly running costs (2 hours a day over 52 weeks)
3kW 49p £6.86 £27.44 £356.72
15 kW £2.45 £34.30 £137.20 £1,783.60

Air source heat pump

A 4 kW air source heat pump could meet the demand of a 2 bed house while a 16 kW model is suited to a well insulated 5 bed or poorly insulated 4 bed.

Air source heat pump output Running cost per hour Weekly running costs (2 hours a day) Monthly running costs (2 hours a day for 28 days) Yearly running costs (2 hours a day over 52 weeks)
4 kW 65p £9.10 £36.40 £473.20
16 kW £2.61 £36.54 £146.16 £713.44

Find the right size heat pump for your home.

Immersion heater

The size immersion heater you'll need comes down to the capacity of your hot water cylinder and the temperature you want the water to reach.

Our guide to immersion heaters will help you to find the size you need.

Immersion heater size Running cost per hour Weekly running costs (2 hours a day) Monthly running costs (2 hours a day for 28 days) Yearly running costs (2 hours a day over 52 weeks)
3kW 49p £6.86 £27.44 £356.72
6kW 98p £13.72 £54.88 £713.44

How much do solar panels cost?

Solar PV panel costs depend on the size of the system and the rates set by the installer.

The table below will give you an idea of how much a solar PV is likely to cost based on the size of the system. But to put the sizes into context, a 3 bed house will need a 3-4 kW system.

Size of the solar PV system Typical cost without installation
1 kW £1,840
2 kW £3,680
3 kW £5,520
4 kW £6,040

An array of solar thermal panels can cost between £3,000 and £7,000. Before you invest in solar thermal, you'll need to make sure that your hot water cylinder is solar compatible.

*According to The Energy Saving Trust: https://energysavingtrust.org.uk/about-us/our-data/

Nick Geary

About the author

Nick Geary

Nick has a wide range of experience writing about conventional and renewable heating solutions, and is always increasing his knowledge by researching any new heating technologies on the horizon.

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