If you’ve been researching solar panels, you’ve probably come across terms like kWh, MCS certification, hybrid inverter or DNO approval. While these phrases are second nature to the solar industry, they can seem confusing if you’re just starting your renewable energy journey.
At SolarTherm UK, we believe choosing a solar PV system shouldn’t require learning a new language. That’s why we’ve created this easy to understand solar dictionary, explaining the most common terms you’ll encounter when comparing quotes, speaking to installers or researching solar energy.
Whether you’re considering solar panels, battery storage, EV charging or energy independence, this glossary will help you understand the technology with confidence.
A
AC (Alternating Current)
The type of electricity used throughout UK homes and businesses. Solar panels generate DC (direct current) electricity, so an inverter converts it into usable AC electricity to power your home.
Array
A solar array is the complete group of solar panels installed on your roof or ground mounted system. The size, orientation and layout of the array directly affect how much electricity your system generates.
B
Battery Storage
A solar battery stores surplus electricity generated during the day so it can be used later, such as during the evening, overnight or during a power cut (with compatible systems). Battery storage helps increase your solar self-consumption and reduce reliance on the grid.
C
Carbon Dioxide (CO₂)
A greenhouse gas that contributes to climate change. Generating electricity from solar panels helps reduce reliance on fossil fuels, lowering carbon emissions.
D
DC (Direct Current)
The type of electricity produced by solar panels and stored in batteries. An inverter converts DC electricity into AC electricity for use around your home.
DNO (Distribution Network Operator)
The company responsible for managing the local electricity network. Most solar installations require notification or approval from the DNO to ensure the local grid can safely accommodate your system.
E
EPC (Energy Performance Certificate)
An EPC measures the energy efficiency of a property, ranging from A (most efficient) to G (least efficient). Improving your home’s energy performance can reduce bills and increase property value.
EPS (Emergency Power Supply)
An Emergency Power Supply allows selected circuits or sockets in your home to continue operating during a power cut using energy stored in your battery. Not all battery systems include EPS as standard.
EPVS (Energy Performance Validation Scheme)
An independent consumer protection scheme that helps ensure renewable energy installations are designed and quoted accurately, giving customers confidence in projected savings and system performance.
F
Feed-in Tariff (FiT)
The Government inventive that paid homeowners for generating renewable electricity. The scheme closed to new applicants in 2019 but existing participants continue to receive payments for the remainder of their agreement.
G
Grid Tied (On-Grid) System
A solar PV system connected to the National Grid. Surplus electricity can be exported, while electricity can still be imported whenever your solar panels aren’t producing enough energy.
H
HIES
The home Insulation & Energy Systems Contractors Scheme provides consumer protection, including deposit protection, insurance backed guarantees and access to dispute resolution.
Hybrid Inverter
A hybrid inverter manages both your solar panels and battery storage within a single unit. This is now one of the most popular choices for modern residential solar installations.
I
Immersion Diverter
A device that automatically sends surplus solar electricity to heat your hot water cylinder instead of exporting it to the grid, helping maximise your self-generated energy and saving money on your hot water bills.
Import
Electricity purchased from the National Grid when your home requires more energy than your solar panels or batteries can provide.
Inverter
Often described as the heart of a solar PV system, the inverter converts DC electricity into usable AC electricity. Common types include string inverters, hybrid inverters and microinverters.
K
kW (Kilowatt)
A measurement of power. Solar systems are typically described by their peak output, for example a 5kW solar PV system.
kWh (Kilowatt hour)
A measurement of energy. Your electricity bill is based on how many kilowatt hours you use and your solar panels generate electricity measured in kWh.
M
MCS Certification
The Microgeneration Certification Scheme (MCS) is the recognised UK quality standard for renewable energy installations. Choosing an MCS certified installer is essential if you want to access Smart Export Guarantee (SEG) payments.
Monocrystalline Solar Panels
The most common type of residential solar panel today. Manufactured from a single silicon crystal, they offer excellent efficiency, reliability and a sleek all-black appearance.
Mounting System
The framework used to securely fix solar panels to your roof or onto ground mounted structures.
MPPT (Maximum Power Point Tracking)
Technology within an inverter that continually adjusts operating conditions so your solar panels generate the maximum possible power throughout the day, even as sunlight levels change.
O
Off-Grid System
A solar installation that operates independently of the National Grid. These systems rely on battery storage and often a backup generator, making them suitable for remote properties.
Optimiser
A small device fitted behind individual solar panels that improve performance when there is partial shading or multiple roof orientations. Unlike a standard string system, optimisers allow each panel to perform independently.
P
Perovskite Solar Cells
An emerging solar technology showing significant promise for future efficiency improvements. While still largely in the research and development stage, perovskite technology may become part of future residential solar systems.
Photovoltaic (PV)
The scientific term for solar panels that convert sunlight directly into electricity.
Polycrystalline Solar Panels
An older type of solar panel manufactured using multiple silicon crystals. They are generally less efficient that modern monocrystalline panels and are now much less common.
S
Self-Consumption
The proportion of electricity your home uses directly from your solar panels instead of exporting it to the grid. Adding battery storage usually increases self-consumption significantly.
Smart Export Guarantee (SEG)
A Government backed scheme requiring participating electricity suppliers to pay homeowners for surplus renewable electricity exported to the National Grid. Your installation must meet eligibility criteria, including MCS certification.
String Inverter
A single inverter connected to multiple solar panels. This remains a popular and cost effective option for roofs with minimal shading and a single orientation.
Solar PV
Short for Solar Photovoltaics – the technology that converts sunlight directly into electricity.
Solar Thermal
Solar thermal panels use the sun’s heat to warm water rather than generate electricity. They have become less common as modern solar PV systems combined with batteries and intelligent controls have become increasingly efficient.
T
Thermodynamic Panels
A renewable heating technology that extracts heat from the surrounding air to produce hot water. Although sometimes associated with solar, they operate differently from solar PV and solar thermal systems.
Z
Zappi EV Charger
A smart electric vehicle charger designed to work alongside solar panels, allowing you to prioritise charging your car using surplus solar electricity rather than importing energy from the grid.
Why Understanding Solar Terminology Matters
Having a basic understanding of solar terminology makes it much easier to:
- Compare quotes from different installers
- Understand how your solar PV system works
- Make informed decisions about battery storage and EV charging
- Understand your expected savings and return on investment
- Feel confident discussing your options with installers
At SolarTherm UK, we pride ourselves on explaining everything in plain English. No confusing jargon, no unnecessary technical language – just honest advice from experienced solar professionals.
Ready to Start Your Solar Journey?
Whether you’re considering solar panels, battery storage or a complete home energy solution, for your Essex, Kent, Suffolk or Hertfordshire home, SolarTherm UK is here to help.
Our experienced in-house team will explain every stage of the process in clear, straightforward language and design a system bespoke to your needs.
Contact SolarTherm UK today for a free, no obligation quote and design, tailored to your property, usage and future energy needs. No hard sell, just honest, expert advice – and the time you need to make an informed decision.
Your home. Your energy. Your future.
Frequently Asked Questions
PV stands for Photovoltaic, which describes the process of converting sunlight directly into electricity.
A kW measures power (how large your solar system is), while a kWh measures energy (how much electricity is generated or used).
Solar panels produce DC electricity, but UK homes use AC electricity. An inverter converts the electricity into a form your home can use safely.
The Smart Export Guarantee is a scheme that pays eligible homeowners for exporting excess electricity generated by their solar panels back to the National Grid.
Every installation is either notified to or approved by the local Distribution Network Operator (DNO), depending on the size and type of the system being installed.
