guide

A guide to energy saving light bulbs, and how to choose the best for your home

22 November 2021 | Celia Topping

We have a lot to thank Thomas Edison for. Without the humble light bulb, life would be dark, dismal, and downright inconvenient. But, as energy efficiency plays an increasingly important role in our lives, we’re looking at alternatives to Edison’s original incandescent bulb. 

Why? Mainly because these old fashioned filament light bulbs use a lot of energy. And that generates lots of carbon emissions. 

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. 

Benefits of energy saving light bulbs

Making a switch to energy saving bulbs can make a big difference in 2 ways:

The Energy Saving Trust has worked out that if you replaced all the bulbs in your home with LED bulbs, you could reduce your carbon emissions by up to 40kg a year. That’s around the same amount of emissions as driving your car 140 miles1

Lighting makes up around 15% of the average home’s electricity bill. The Energy Saving Trust says that for every 60 watt bulb in your home, you could save up to £3 per bulb per year (based on a 660-lumen bulb running for 445 hours a year2).

What happens to the energy wasted by the light bulb?

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 heat3.

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

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.

Types of energy saving light bulbs

We’ve seen how inefficient incandescent bulbs are. In fact, the EU started to phase them out4 as early as 2012. 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. The sale of halogen bulbs has been banned since September 20215.

Compact fluorescent light bulbs

Compact fluorescent light bulbs, or CFLs, were the first real energy saving light bulbs to replace incandescents. You might remember them as that spiral shaped tube bulb that had a slight delay between flicking the switch and the light coming on. When it did come on, it took a few more seconds to achieve full brightness. This put a lot of people off buying them. 

Despite these initial teething troubles, CFLs use 20–33% less electricity and last 8–15 times longer than Edison’s bulb6. Plus, CFL tech has improved over the last few years, so those delays are no longer an issue. 

There is one downside: they contain mercury. This can cause environmental concerns when they break and are thrown away. The sale of CFLs will be banned from September 2023.

Light-emitting diodes (LEDs)

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 report7, “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 more energy to light and emits very little heat. This means they need less energy to produce the same amount of light as a traditional bulb.

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

How to choose the right energy saving bulbs for your home

ultimate guide to energy saving lightbulbs

Lighting isn’t all about energy efficiency. After all, you want to get the right atmosphere for different rooms in your home too, right? Maybe you want a cosy bedroom, or a bright kitchen. It can all be achieved with the right kind of lighting. And if you can do that while saving energy 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.

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

  • Fitting: check the bulb fitting on your light fixture and write down the code. 
  • Shape: decide how you want the light to appear – directional or omnidirectional (more on this below) – as different shapes give different spread and angle of light.
  • Brightness: the output of light from a bulb is measured in lumens. The more lumens a bulb provides, the brighter it is.
  • Temperature: are you lighting a cosy, warm room, or a modern, bright, minimalist space? The colour of light is measured in Kelvins, which is actually a measure of temperature. The numbers on the side of the bulb packaging show what colour of light the bulb will emit.  
  • Cost: it pays to shop around. Good LEDs are now available at lower prices. Check the likes of eBay, Argos, and your local DIY stores. 

Read on below to find out more:

1. Which light bulb fitting do you need?

We have a few types of fittings in the UK:

  • Several different sizes of bayonet (twist and lock base)
  • Several different sizes of Edison screw cap
  • Several sizes of push and fit 

Be sure to check which one you have before you go shopping. Ideally, just take the bulb with you, to be safe. 

2. Which shape of bulb do you need?

light bulb shapes

Different bulb shapes throw different kinds of light. These are broadly divided into 2 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. That’s omnidirectional. 

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

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”. 

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?

When LEDs first came onto the market, they cast a very white, sterile kind of light – much colder than the warm, orange-y glow we were used to from incandescents. That soon changed, and nowadays LEDs are available in all sorts of colours and ‘temperatures’.

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”. Orange-y, warm light, like that of a candle, is around 1500k. Bright daylight is much colder, around 5000k. 

We’re creatures of habit, so the most popular type of household bulb is still the “warm white” of the old incandescent (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?

 energy saving light bulbs

Today’s LEDs are cost effective, because they last for a long time and use less energy. Depending on what you’re looking for, they start at around £1–3 per bulb. Spending £6 on a top-quality LED, which will last for many years and use a fraction of the energy of an incandescent, can be a good investment. 

A article in The Guardian explains how our lighting electricity bills could be cut by 90% just by switching to LEDs. If every UK home switched to LEDs, we could also save as much as 8 million tonnes of carbon from being released into the atmosphere. In fact, the amount of energy saved during peak hours would be the same as the output of 3 power stations8. Talk about a light bulb moment.

How else can I make my home more energy efficient?

Switching your light bulbs is just one way you can make your home more energy efficient. See our guide to energy efficiency at home for more ideas. 

Make your home smarter and more efficient with OVO

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

A smart thermostat means you can control your heating from wherever you are. You can change the temperature, and turn your heating on or off – all from your phone, tablet, or other device. 

Here’s a quick summary of all the main benefits of having a smart thermostat:

  • Control your heating from anywhere, all via an app on your phone, tablet, or other device
  • See your home energy data which could help you make changes to use less energy 
  • Saving energy means you’ll reduce your carbon footprint

To find out even more about smart thermostats, read our guide. All OVO members get £79.999 off a wireless tadoº Smart Thermostat, which can help you reduce your energy use from heating by up to 31%9.

Energy-saving light bulbs FAQs

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! 

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

  • If your goal is to help reduce carbon emissions, then you should switch to LEDs now
  • In general, bulbs used more often should be replaced first, to maximise 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. Even so, swapping now starts your energy saving sooner - so why not switch today?

This usually happens with low-quality LEDs, because the diodes inside can pick up even the slightest electric current and dimly light up. The fault is actually in the light fitting, rather than the bulb. 

For the household, the brightest bulb on the market is the Philips 5000 lumen LED bulb. It’s huge, at 5.28 x 5.28 x 12.13 inches – that’s as tall as a bottle of wine!

LEDs can be disposed of in your general waste bin, as there are no hazardous elements.

LEDs and halogen light bulbs don’t contain mercury, but CFLs do.

Yes! Just take your electric fire bulb out of your fire and take it along to your local DIY store. They should be able to help you find the right LED to fit your fire.

Sources and references:

1 https://energysavingtrust.org.uk/advice/lighting/

2 https://energysavingtrust.org.uk/getting-best-out-your-led-lighting/

3 https://www.mrsec.psu.edu/content/light-bulb-efficiency#:~:text=Only%2010%25%20of%20the%20energy,90%25%20is%20lost%20as%20heat.

4 https://www.theguardian.com/environment/2012/aug/31/lightbulbs-incandescent-europe

5 https://www.gov.uk/government/news/end-of-halogen-light-bulbs-spells-brighter-and-cleaner-future

6 https://www.moneycrashers.com/incandescent-vs-compact-fluorescent-light-bulbs-cfl/

7 https://www.goldmansachs.com/insights/pages/new-energy-landscape-folder/report-the-low-carbon-economy/report-2016.pdf

8 Saving based on manufacturer's recommended retail price of £199.99.

9 An independent study has shown that installing and correctly using a tadoº smart thermostat can reduce your energy use from heating by up to 31%. The study found that the tadoº device can reduce heating energy requirements by 14-26% through controlling the heat source (e.g. boiler or heat pump). You could also save another 7% by turning down the heating based on the weather forecast, depending on the window sizes. If the window surfaces are relatively large, the energy saving will increase.

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