Solar case study: Find out how this homeowner is saving hundreds of pounds per year

Leila Hodgkins tells One Home all about her experience of installing solar panels at her home in Somerset where she lives with her husband David, and explains the significant cost savings that they are now enjoying. Leila and David work from home, and have PCs running for most of the day. They also have an electric vehicle.

For a long time, we’ve been looking at ways to reduce our carbon footprint and have been following the developments of different low carbon technologies. A few years ago, we decided to bite the bullet and install solar panels on our four bedroom semi-detached cottage. It’s an old property, dating back to 1890, so we had to be sure that panels would be suitable.

We have a pitched roof (it slopes) and it’s in good condition. It’s also south facing so our house is well suited to solar.

Finding an accredited installer

We searched for approved suppliers in our area and selected a company, based on their good reviews, to assess the house for suitability and explain to us what was involved. It’s important to make sure the installer has accreditations from the Microgeneration Certification Scheme (MCS) to ensure they meet high quality standards for solar panel installation.

Our installer had accreditation from MCS as well as the National Association of Professional Inspectors and Testers (NAPIT) and the Energy Performance Validation Scheme (EPVS). You can ask to see their certificates if you want to be sure.

They also dealt with the local authority to inform them about the installation. This is for building regulations if you live in a listed buildings or conservation area rather than for planning permission, which is not required for the majority of domestic solar installations.

The work took place in December 2022. The installation company put up their own scaffolding tower and the work was done in just one day. It took another two or three weeks for the system to be certified and connected to the grid. It was a smooth process that was handled mostly by the installer.

Battery plus points

The system consists of eight solar panels which together can generate a maximum of 3.3 kilowatts (kW) plus a 6.5 kilowatt hour (kWh) battery. You can choose a system that doesn’t have a battery but we wanted one as it allows you to store the energy produced by the panels rather than relying on drawing energy from the grid once the panels are no longer generating.

With a 6kWh battery, we could draw an average of one kilowatt of electricity per hour for six hours or 500 watts for 12 hours. To give an indication of how much different energy appliances use, a fridge freezer uses around 0.75 kWh each day and a desktop computer uses around 1.12kWh over eight hours.

The battery is physically quite large – it’s around 55cm x 50cm and around 25cm deep – so you need to have space for it to be bolted to a wall. Many people have it installed in a utility room or garage.

In addition to the battery, your installation will include a piece of kit called an inverter. The inverter manages the flow of electricity that is generated, how it is used and whether it is exported to the grid. This is also about 50cm x 50cm, so you will need space for this too.

What tariff to choose

After the installation, we switched energy supplier to Octopus Energy as it was the only supplier at the time to offer a ‘feed in tariff’ – the payment we receive for the energy we generate but don’t use and then export to the grid. It’s important to be on a tariff that is suited to your system and the installer should be able to advise on this.

Our tariff also has a cheap overnight unit rate which we chose because we have an electric vehicle which we charge at night.

When the battery is low, it tops up overnight from the grid, which it does on the cheap rate of electricity. In the summer, it tops up only a small amount in this way. In the winter, the battery is often empty by the end of the day in which case it will draw from the grid overnight back to full capacity.

How it works

In reasonable daylight, the solar panels power the house so we have free power. If there’s not enough daylight, the house draws from the battery. After the power in the battery is used up, electricity is drawn from the grid. This is all managed by a solar inverter, which automatically balances where the electricity is coming from, as well as allowing you to feed excess electricity back to the grid. It’s very clever! The inverter comes with an app, which shows how the electricity is being distributed, what you’re using and how much you are earning if any power is being fed back to the grid. Everyone with solar panels loves their app as it shows how much free electricity you’re getting, and what you’re getting paid!

The numbers

The installation cost was £11,300 including VAT and almost half of that was the cost of the battery, although this was a few years ago and installation costs have risen to around £13,000 – £15,000*. Typically, a 4kW system suitable for a two or three-bedroom house costs around £6,000* without a battery.

We became owners of an electric vehicle in August 2021. In the 17-month period when we had an electric vehicle but before the panels were installed (August 2021 to December 2022), our average electricity bill was £99.36 per month – not including the standing charge.

Since the installation, our average electricity bill is now £38.37 (January 2023 to February 2025). However, when you take into account the payments we have received for electricity we have exported back to the grid, the monthly bill is even lower – just £30.11 per month. It’s a big saving of nearly £70 per month, on average, which is impressive given the rising energy prices over that period. That’s an annual saving of around £840. In total, we have received £214.80 in feed in tariff payments over the past two years, which is very satisfying!

Generally speaking, you’d expect to break even on the installation cost after seven to 10 years, depending on the size of the property and the system. If you don’t buy a battery there will be a far quicker pay back. In addition, the solar panels will improve your Energy Performance Certificate (EPC) level, which is how homes are rated for the cost of heat and power. A better EPC can help homeowners with cheaper loans through access to green mortgages and other financial products.

The final word

I’m really glad we went ahead with the installation. I love the fact we are more self-sufficient with our energy usage and it’s incredible to see our smart metre reading ‘0’ when the sun is shining. There have been some months in the summer when we have generated more electricity than we have used and therefore we are in credit, which is particularly pleasing.

It is a big upfront cost, particularly because we chose to have a battery which added to the price, but it’s brilliant to know we have made a positive investment in our home and taken important action for the climate.

*The estimated installation costs quoted in this article are correct as of March 2025.

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