Solar Panel Calculator

Solar Panel Costs and Savings Calculator

When first thinking about solar panels for your home, there is a lot of information to get through and a lot to consider. The start of this journey can raise a lot of questions, the most common of which are, “how much will solar panels cost and how much will I save?”

Getting answers to these questions can be tricky at first, especially when dealing with a complex technical subject like Solar Panels. Finding out how many solar panels you will need, the space required to fit them, and how many kilowatt hours are going to be generated can seem like a lot of working out!

This is why we at SolarTherm UK developed our Solar Panel Calculator – to give an instant estimate for the cost of solar panels, and the potential savings on your electricity bill as easily as possible.

Why use a Solar Panel Calculator?

Solar Panels are a home improvement investment, and like most investments, one of the major factors is determining the costs involved. However, as properties can vary in size, shape and design, the cost of retrofitting solar panels will vary from one house to another – meaning the cost finding process can often lead to a number of questions.

What size solar panel system is right for you?

One of the main factors when considering solar panels is the size of the system. This will primarily be determined by the available space. Our solar panel calculator will show how much space will be required to install a given number of solar panels, making it easier to find out what is possible for you!

How do I calculate how many solar panels I need?

Knowing how many solar panels you need to power your home is a key consideration when thinking about investing in solar. But how do you figure that out? There are complex methods involved in calculating the generation from solar panels, as outlined by accrediting bodies such as MCS and EPVS. Our solar panel calculator does all this calculation behind the scenes, so all you need to know is how much electricity you use!

How much will it cost to install a solar panel system?

Our solar panel calculator will give a cost estimate for installing solar panels based on the configuration you choose. All you need to tell us is how many panels you need, your battery storage options and how much electricity you use!


How to use the Solar Calculator

Choose the number of Solar Panels

Solar Panel Calculator: Number of panels.

Select the number of solar panels you are considering. If you are unsure, the average semi-detached roof can accommodate 12-16 panels. The solar calculator will advise how much roof space you require.

You should base this selection on the section of your roof that is closest to south-facing.

Learn more about solar panel orientation…


Select your Battery Storage Option

Choose an option for battery storage.

Battery storage systems are designed to help you use more of the electricity that is generated by the solar panels, instead of exporting that energy to the grid.

Learn more about solar panel battery storage…

Solar Panel Calculator: Battery Storage selector

Enter your annual Electricity Usage

Solar Panel Calculator: Annual Energy Usage.

Enter the amount of electricity you use in a year.

This figure allows the calculator to estimate how much of the solar-generated electricity you will use, and therefore, how much you will save on your energy bill.

Your annual electricity usage will normally be shown on your electricity bill, and will be shown in Kilowatt Hours (kWh).

Solar Panel Calculator: Costs and Savings Explained

Your Estimate

This is the estimated cost of the solar panel system based on the number of panels and the battery storage selection you have made.

The cost generated here is based on data for previous installations, but it is worth noting that every installation has different requirements, so costs can vary, both up and down. Different roof types, system configurations, and access requirements (eg. scaffolding) can alter the cost of an installation significantly. Find out more about solar panel installation costs…

To get a fully tailored cost and system design, contact us for a quote…

Your Bill Savings

The solar calculator will estimate how much you could save on your electricity bill based on the solar panel system configuration and your current annual electricity usage.

This is calculated based on how much electricity we would expect the selected solar panels to generate. This data is based on average data from the South-East UK (our main operating area). Actual efficiency will vary from one installation to another, due to orientation, shading and various other factors. Find out more about solar panel orientation and shading.

The bill savings calculation will also change based on battery selection. As a solar battery storage system allows you to use more of the energy you generate, the bill savings will typically increase with more battery storage. In reality, this will depend on your particular level and patterns of electricity usage. Find out more about solar panel battery storage…

To get a more accurate savings projection showing the total savings over the lifetime of the system, contact us for a custom quote…

Return On Investment

The return on investment represents the amount of time it would take for the savings to outweigh the cost of installation.

For most home solar panel systems, the return on investment period is between 5-10 years, but again, this will depend on all of the combined factors mentioned above.

EPVS Energy Performance Validation Scheme Logo
MCS Certified Logo
EPVS Energy Performance Validation Scheme Logo
HIES Accredited Member badge
NIC EIC Logo
Standard CHAS Badge