Solar Energy Jargon Explained

It seems with every technology, even solar panels, there is a wealth of jargon that most people are not familiar. If you are planning on purchasing solar panels, here is some of the jargon that you need to know.


This is a PV solar cell that consists of thin layers of silicon sprayed on a backing material to make solar roof tiles. The thin layer of silicon is thinner than the silicon wafers normally used on solar panels, which means that the cost is less.

Active Solar

This is using the collector or solar panel to capture sunlight to heat water or directly convert to energy.

Drain-back System

This is a solar water heating system where the water inside drains into a small bottle when the pump is off, which protects the entire system from damage either through freezing or boiling.

Evacuated Tubes

This is a type of solar water-heating panel that collects the sun’s energy to heat water running through containers at the top of the tubes.


This is the program that lets you receive payments from the government when generating power using solar panels. Also, you can sell excess electricity back to the national grid.

“Free Solar”

This is a program where companies pay for installation and own the solar panels of which you use the energy generated for free. The companies collect money from the Feed-in-Tariff.


KiloWatt Peak, which is a unit of measurement for the max amount of electricity your solar panels generate.


This stands for Microgenerational Certification Scheme. This is certification for companies that use microgenerational technologies such as solar panels. The MCS qualifies these companies for Feed-In-Tariff payments.


This is low-capacity electrical generation equipment up to 50 kW. This covers a wide range of technologies for solar and wind electrical generation.

Monocrystalline silicon cells

The most expensive, but efficient solar panel cell, it is created from crystals of silicon and capture up to 15% of the sun’s energy.

Multicrystalline silicon cells

Solar panels made from silicon wafers that are less expensive, but also less efficient than monocrystalline cells.

Passive Solar

Using solar energy without solar panels, this describes using insulation to minimise heat loss and large, southern-facing windows to let in sunlight to heat the home.

Photovoltaic PV

Thin layers of PV cells, usually silicon that generate electricity when exposed to light, they are often used in multiples to capture and transmit more electricity.

Pressurised System

The water that is pumped through solar panels and heated. This water flows through a heat exchanger which heats the hot water cylinder.


This stands for Renewable Energy Assurance Limited. The Consumer Code of REAL sets standards for microgeneration technology companies for MCS certification.

Renewable Heat Incentive (RHI)

This is a financial program that pays homeowners for generating heat, similar to the Feed-In-Tariff for electricity.

Solar Tiles

Solar tiles are similar to photovoltaic cells, but smaller and narrower than PV panels.

Solar Water Heating

Water that is heated when pumped through a solar panel. The heated water goes through a heat exchanger and warms the water in your hot water cylinder.