The ultimate guide to energy-saving light bulbs, and how to choose the best for your home

17 December 2020 | Celia Topping

Energy saving light bulbs

Right now, you’ve probably got at least 10 to 20 of them in your home. And without the humble lightbulb, life would be dark, dismal and downright inconvenient! 

We have a lot to thank Thomas Edison for. But, as energy-efficiency plays an increasingly important role in our lives, it’s time to turn the light out on Edison’s incandescent bulb, for good. 

Why? Mainly because these old-fashioned filament light bulbs use a lot of energy. And we know that generates lots of carbon emissions – which, in turn, causes global warming and climate change

What are energy-saving light bulbs?

Energy-efficiency is all about squeezing out every last bit of power, and not letting any go to waste. So, an energy-saving bulb uses less electricity to emit the same amount of light as a traditional bulb. 

FACT: It’s astonishing to know that only 10% of the energy used in traditional incandescent bulbs is converted to light. The other 90% is lost as heat1 (hence the name ‘incandescent’, due to the glowing hot filament inside).

Incandescent bulbs are simply not energy-efficient! But energy-saving bulbs can improve on this – by varying amounts. More on that in a moment. 

Energy-saving light bulbs use less energy, and therefore reduce the carbon footprint of your home. And, crucially, using less energy means paying less for your bills. It’s a win for the environment, and a win for your wallet. 

Looking for light bulbs that can do even more? Read our guide to smart light bulbs, how to choose them, and how you can control them remotely.

What types of energy-saving light bulbs are available?

We’ve seen how inefficient incandescent bulbs are. In fact, the EU started to phase them out as early as 2009. So what else is out there?

Halogen bulbs

Halogen light bulbs were invented in the mid 1950s. They use less energy and last longer than traditional incandescents. That’s because of their halogen gas content – which makes them about 3 times more efficient than incandescent bulbs.

Following further energy-efficiency developments, halogen bulbs began being phased out in 2016, although you’ll still be able to find them on some shelves.

Compact fluorescent light bulbs

Compact fluorescent light bulbs, or CFLs, were the first real energy-saving light bulbs to replace incandescents. You’ll probably remember them as that spiral-shaped tube bulb that had a slight (and slightly annoying) delay between flicking the switch and the light coming on.

And when it did come on, it took a few more seconds for the bulb to achieve full brightness – which put a lot of people off buying them. 

Despite these initial teething troubles, CFLs use 75% less energy and last 10 times longer than Edison’s bulb. Pretty impressive. Plus, CFL tech has improved over the last few years, so those delays are no longer an issue. But a downside is the mercury they contain. This can cause environmental concerns when they break and are disposed of. 

Light-emitting diodes

Since light-emitting diodes (LEDs) hit the shelves, there’s been no looking back. Their superior technology, light quality and energy-saving credentials have put LEDs in the spotlight as the number one choice for bulbs. 

In fact, according to a 2016 Goldman Sachs report, “the rapid adoption of LEDs in lighting marks one of the fastest technology shifts in human history.” 

Remember that fact about incandescent bulbs only converting 10% of their energy to light? Well, an LED converts over 90%, and emits very little heat. This means they need far less energy to produce the same amount of light as a traditional bulb.

And you won’t have to worry about changing an LED too often. They can have a staggering 34 years lifespan, in comparison to an incandescent’s 1.4 years. 

How to choose the right energy-saving bulbs for your home in 5 easy steps

ultimate guide to energy saving lightbulbs

Lighting isn’t all about energy-efficiency. After all, you want to achieve the right atmosphere for different parts of your home too, right? Maybe you want a cosy reading nook, a vintage-esque lounge, or a bright modern mood for your kitchen.

It can all be achieved with the right lighting to accentuate your furnishings. If you can do that while saving energy and money, and cutting your carbon footprint, then you’re onto a winner! 

There are a lot of different types of bulb on the market today, all designed to do slightly different things. It can be a bit overwhelming – so here’s a helpful guide to help light your way.

1. Which light bulb fitting do you need?

We have a few different types of fittings in the UK – so check which one you have before you go shopping. If there’s already a bulb in there, take it with you, to be sure you get the right one. 

2. Which shape of bulb do you need?

Different bulb shapes throw different kinds of light. These are broadly divided into two categories – directional or omnidirectional. For example, a typical light hanging from the ceiling (called a pendant light), needs a bulb that throws light around the whole room.

So you’d be best buying an arbitrary, stick or spiral bulb for omnidirectional light. Lamps, on the other hand, generally use candle bulbs – whereas a spot bulb would be best for a spotlight. 

common lightbulb shapes

3. How bright does it need to be?

When we only used incandescent bulbs, it was fine to gauge brightness in terms of power – measured in watts. Nowadays, with LEDs and CFLs being so energy-efficient, much less power is needed for the same brightness. So instead of watts, brightness is measured in ‘lumens’. 

The chart below gives the equivalent measurements for different types of energy saving bulbs compared to standard bulbs. Brightness is at the top, measured in lumens. Below that, you can see the different bulbs and their equivalent brightness. 

how many lumens do you need?

For example, to get the same brightness as a standard 60w bulb, you’d need 700 lumens. Replacing that 60w bulb with an LED would mean buying a 10w LED bulb. That shows just how much more energy-saving an LED bulb is. Essentially, 6 times less power is needed for the same brightness!

4. How warm do you want the light to be?

Remember when LEDs first came onto the market? They cast a very white, sterile kind of light – much colder than the warm, orangey glow we were accustomed to from incandescents. That soon changed, and nowadays LEDs are available in all sorts of colours and temperatures.

But before you buy a new bulb, you still need to know how ‘warm’ you’d like your light to be, to avoid any glaring errors!

The temperature of light is measured in ‘kelvin’. Orangey, warm light, like that of a candle is around 1500k. Bright daylight is much colder, around 5000k. Here’s a scale in kelvin, to give you a clearer idea:

light temperature

We’re creatures of habit – so the most popular type of household bulb is still the ‘warm white’ of the old incandescant (2700k). But in kitchens and bathrooms, many people prefer a slightly less yellow light, called ‘natural white’ (3000k).

In very modern, minimalist homes, an even cooler white (4000k) might suit. But be warned – anything above 5000k starts to have a bluish tint.  

5. How much will you have to pay?

When LEDs first came onto the market, they were 10 times more expensive than the equivalent incandescent. But with time, costs have dropped and they’re now only a few pounds more than a traditional bulb.

That makes them extremely cost-effective, because they last far longer and use less energy. Spending £6 on an LED, which will last for many years and use a fraction of the energy of an incandescent, is a prudent purchase!

A recent article in The Guardian explains how our electricity bills could be cut by a whopping 90% just by switching to LEDs. 

“It (switching to LED light bulbs) will shave nearly £2bn off the energy bills for Britain’s 25m homes. It will stop as much as 8m tonnes of CO2 entering the atmosphere and the energy saved at peak time equates to the output of three power stations the size of Hinkley Point C.” 

Talk about a lightbulb moment! 

Are energy-saving light bulbs worth the switch?

ultimate guide to energy saving lightbulbs

Without a doubt! The simple, everyday act of changing a light bulb lowers your electricity bill and reduces your carbon footprint. And with their many shapes and colours, there’s no need to compromise on style or brightness delays.

Many LEDs are dimmable too. There’s nothing an incandescent bulb can do that an LED can’t... except waste energy, and cost you money! 

Is it better for the environment to swap out your light bulbs now, or wait until they need replacing?

Very good question! A study from the University of Michigan found that:

  • If your goal is to help reduce carbon dioxide emissions, then you should switch to LEDs now
  • In general, bulbs used more often should be replaced first, to maximize energy savings
  • Replacing a bulb before it burns out may seem wasteful, but you can cut your energy use by doing it

So if you have an old incandescent in your attic that perhaps only gets used for 10 hours a year, there’s no point in switching. But for your kitchen/lounge, where the lights stay on for hours a day, every day, making the switch is definitely a good idea.

In years to come, there might be a cheaper bulb that uses less energy, but swapping out now starts your energy-saving sooner – so why not switch today?

How else can I make my home more energy-efficient?

Switching your light bulbs is just one easy and affordable way you can make your home more energy-efficient, and save money. Using a smart meter and In-Home-Display is another. Find out how to get one installed for free

And don’t miss out on the Green Homes Grant  which could give you £5,000 towards home insulation and double glazing, to make your home even more snug this winter.

But the energy-saving doesn’t stop there. Being a bit more savvy with your water and heating can save you hundreds a year. Discover 120 more simple ways you can cut your household bills and reduce your carbon footprint in our easy-to-follow guide. And remember, by switching to OVO, all your electricity will be 100% renewable2

Get a quote today and find out how easily you can save energy and money. Let’s do our bit for the planet! 

Just to recap: the 5 steps to find your perfect light bulb!

To make sure you get the best bulb for your home, consider your space, and remember these 5 easy steps: . 

  1. Fitting: check the bulb fitting and write down the code. 
  2. Shape: decide how you want the light to appear – whether directional or omnidirectional, and check our handy illustration above for the right bulb shape. Or ask for advice when you go shopping. 
  3. Brightness: check the diagram above to see how many lumens you need. 
  4. Temperature: are you lighting a cosy, warm room, or a modern, bright minimalist space? Check out the kelvin scale above, to see which bulb temperature would best suit. 
  5. Cost: it pays to shop around. Good LEDs are now available at affordable prices. Check the likes of ebay, Argos and your local DIY stores. 

If you're interested in making your home greener and smarter, have you thought about getting a smart thermostat? OVO has just teamed up with tado°, to give our members the chance to buy a smart thermostat directly through us! 

You'll be able to link your fancy piece of kit directly to your My OVO account. And we'll connect your smart meter data to your heating – giving you personalised tips to help cut heat waste at home. Find out about smart thermostats and their key benefits, in our comprehensive guide. 

Not yet a member? Make the switch to OVO and let’s save energy – and the planet – together.

Sources and references:


2The renewable electricity we sell is backed by renewable certificates (Renewable Energy Guarantee of Origin certificates (REGOs)). See here for details on REGO certificates and how these work.  

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