Jargon busters

We get it. You want to make your home more energy efficient, but you want the whole thing to be simple. The good news is it can be. Let’s start by breaking down some of the energy saving jargon…

🕑  9 minutes read

Energy Efficiency

Something we should all be on board with. It simply means getting more for less.

Being energy efficient means using less energy (and therefore spending less money) to get the same results.

For example, an old-style light bulb will light your room, but it also gets hot. It therefore wastes energy heating itself up.

On the other hand, new energy-saving light bulbs create the same amount of light but don’t get as hot, meaning they use less energy overall.

Same results, but more energy efficient.

Energy Performance Certificate (EPC) Rating

You’ll see these in all sorts of places, particularly when you’re looking for a new home. It’s a rainbow-coloured scale with letters A–G that tell you how energy efficient your home is.

A (green) is the highest, G (red) is the lowest.

That means if your home has an A rating, it will be cheaper to run than one with a G rating. It’ll also be better for the environment as it will use less energy.

When you buy a new home, you’ll get an EPC certificate with two ratings. The first tells you how energy efficient the house currently is. The second shows you what the EPC could be if you made some improvements.

Follow through on the EPC’s recommended changes and you could make a cheeky saving on your energy bills. For a ballpark figure, getting a three-bedroom semi-detached house from a ‘G’ to an ‘A’ could save in the region of £4,000 on energy bills over three years!

Source: Energy Saving Trust

Greenhouse gases

A greenhouse lets sunlight in to keep the temperature inside warm, creating the perfect environment for plants.

The earth itself works in a similar way. The greenhouse gases that make up our atmosphere (such as CO2) trap sunlight in order to keep the planet warm, creating the perfect environment for humans like us.

But hang on, aren't greenhouse gases bad? Well, only in large amounts. If we increase the amount of greenhouse gases in our atmosphere, we’ll trap more heat. That could make the earth too hot for us.

That’s why we need to be mindful that we’re not pumping out too many greenhouse gases.

Carbon Dioxide or CO2

CO2 comes from all over the place. Volcanoes spew it out when they erupt. Certain types of soils release it. And animals release a little bit when they breathe out.

All of this is good news for plants, which breathe CO2 and convert it to useful stuff for humans – like oxygen and sugar.

This has been going on since the dawn of time. But more recently, we’ve introduced a new source of CO2: fossil fuels, such as oil and coal.

CO2 is the main greenhouse gas created by humans and what’s more, our homes currently account for around 22% of UK carbon emissions (CO2).

As we know, if we pump out too much greenhouse gas, the earth will heat up, which won’t make living here very pleasant. CO2 should be top of our list for things to watch out for.

Energy Saving Trust


Carbon Emissions

This is just another way of saying “the amount of CO2 we release.”

The lower your carbon emissions, the less you’ll contribute to climate change.

Climate Change

The more CO2 we release, the more sunlight gets trapped in our atmosphere. The more sunlight gets trapped, the hotter the climate becomes.

If the climate gets too hot, terrible things could happen – polar ice caps could melt causing sea levels to rise, parts of the world could become too hot to live in, and tropical storms could become more frequent and more intense.

The data all point to the conclusion that earth’s climate is gradually getting hotter. This is bad, bad news. It’s estimated that there will be an even greater risk of dangerous and catastrophic natural events worldwide, including hurricanes, wildfires, and droughts if the current global average temperature of 1.1°C rises to 2°C.

Source: Energy Saving Trust


The type of energy that doesn’t run out.

There are many examples of renewable energy. Solar energy won’t run out until the sun runs out, so we’ve got a few billion years of energy there. Wind power is a pretty safe bet too. And then there are other types like tidal, geothermal and biomass energy.

Want to get on board with the renewable energy revolution? You can, by installing solar panels on your roof. The best part is not only will you reduce your bills by generating your own energy, you can sell unused energy back to the grid.

Source: Ofgem


This means once it’s gone, it’s gone.

There are limited amounts of non-renewable energy sources on earth.

Fossil fuels, e.g. coal, oil and gas, are all in this category. While these are powerful sources of energy, releasing a lot of energy for a small amount, they also generate a lot of CO2.

Nuclear energy is also non-renewable as it uses uranium. While it doesn’t directly produce CO2, it does create pollution in the form of nuclear waste, which is extremely dangerous to humans and bad for the environment.


If something is sustainable, it means it’s not being used up as quickly as it’s being replaced.

To be sustainable requires two things: that you use renewable sources of energy, and that you are being energy efficient.

That means you’re not using more energy than you need, and the source of your energy can be replaced.


Single-use stuff. The kind of things you use only once, then throw away.

Lots of food-related stuff falls in this category, such as plastic knives and forks, take-away cups and plastic boxes, straws and napkins.

Because disposables often can’t be recycled, they make their way to landfill. This is bad for the environment, which is why we’re encouraged to cut down on our use of disposables.


When something is insulated, the temperature on the inside isn’t affected by the temperature outside.

In the context of your home, it means keeping warm air in and cold air out. If your house is well-insulated, warm air won’t escape, meaning you’ll use less energy to keep your home warm.

There are many ways to stop warm air escaping from your home, ranging from small tweaks to big jobs.

A small tweak could be to install adhesive door strips. These are easy to fit and can stop hot air escaping through the gaps around doors.

A slightly larger change is to install double glazing. Single pane windows lose a lot of heat, while double glazing prevents this from happening.

Big changes can include loft insulation, cavity wall insulation or solid wall insulation. For these, you’ll probably need to call the builders in.

Whichever method of insulation you choose will involve an up-front cost. However, the energy and cash savings you’ll make down the line should make your investment worthwhile. For instance, you should be able to make back the installation cost for your cavity wall in five years or less due to the yearly energy bill savings you will make.

Source: Energy Saving Trust

Updated February 2023