How to guide

Your guide to choosing the right Solar PV system

A brick house with a red tiled roof fitted with solar panels, a green front door, two white-framed windows, and a small paved front yard with outdoor furniture, situated in a residential neighborhood with other brick houses and trees in the background.

What is Solar PV?

PV stands for Photovoltaic, which is a way of using special materials to capture sunlight and turn it directly into electricity.

Two workers installing black solar panels on a red tiled roof of a house during daytime with a clear blue sky.

Can I benefit from Solar? How much can I save?

Yes! If the sun is shining on your roof, solar is a great option for you.

How much you can save depends on your current home energy consumption.

As a rule, the more energy you use already, the more money you can save by switching to solar.

Aerial view of a residential backyard with two houses under construction, a patio, a lawn, and several parked cars, surrounded by a wooden fence.

Is my roof suitable?

Most likely, yes.

Most pitched or flat roofs makes a perfect home for solar.

Rainbow over a green tree and black solar panels on a rooftop, with a cloudy sky in the background.

How many panels should I have?

There are a few ways to size your system.

The first is to design a system to provide the shortest payback period possible. For example your system costs £5k, and you save £1k a year on your energy bills. Your payback time is 5 years!

Another way would be to minimise grid usage, i.e "fill my roof!"

Once appropriate systems have been recommended to you, it really becomes your choice if you want to make any changes.

Aerial view of a two-story brick house with solar panels installed on the roof, surrounded by trees, a garden, and neighboring houses. Scaffolding is set up around part of the house.

I have old panels, should I replace them?

Maybe... It’s complicated.

Be it on your house, your street, or in your local area, you will see many homes that had panels fitted in the last 10-15 years. Most panels from this era are around 200-250Wp (Watt peak). Panel technology has come a long way, and modern panels are now around 430Wp.

As you may have just worked out, modern panels offer almost double the power of older panels. On this basis it may make sense to swap out your old panels for new, higher power panels.

This is true, with one caveat. The Feed in Tariff.

Multiple solar panels installed in a field under a partly cloudy sky.

What is a Feed in Tariff (FiT)?

Most solar installations in previous years were driven by a generous incentive from the Government called the Feed in Tariff.

This was a promise to pay homeowners a fixed price per kWh for energy either exported, or used, or both.

These started out VERY generous, and were gradually reduced until the scheme's end in April 2019.

This complicates the calculation on whether we should swap out an old system for a new. It really has to be viewed on a case by case basis.


Aerial view of a neighborhood with houses, gardens, and solar panels on the roof of a brick house.

Can I get paid for my export, now the FiT is gone?

Yes! Whilst the FiT was retired in 2019, it has since been replaced by the Smart Export Guarantee (SEG).

All major energy providers offer a SEG, and you can apply to whichever provider is offering the best rate.

The only requirements are that you have a smart meter fitted, and your installer is MCS accredited.

MCs Certified logo with white dots forming the letters on a black background.

What is MCS accreditation?

MCS (Microgeneration Certification Scheme) is the UK’s top solar PV accreditation that an installer can achieve.

MCS also issues accreditation for other areas of renewables, such as heat pumps and battery storage.

Text saying 0% VAT on solar.

Are there any grants for solar?

Whilst there are no grants, new solar installations do benefit from a 0% VAT rating.

This includes all parts, materials, labour, anything ancillary to the solar PV install. This is currently due to end April 2027, when it will return to 20% VAT.

Three workers installing solar panels on a sloped, tiled roof of a residential house.

How do I find an installer?

As ever, word of mouth is a great starting point for finding an installer.

Failing that, the MCS website has a “find a contractor” page. We would recommend contacting 3 or 4 local companies. You can cross reference these companies with Google reviews, to check other customers have had a good experience.

Alternatively, if you have found this guide helpful and want to know more, we would love for you to get in touch with us here at Terra Energy Solutions.