Save money with energy-efficient lighting


Lighting can account for over 20% of a typical home’s energy bills (depending on appliances), so making your lighting more efficient is an easy way to save money.



Traditional light bulbs (known as 'incandescent' bulbs) have been lighting homes for over a century, and their design is little-changed – a tungsten filament inside a vacuum bulb. But they are highly inefficient, converting only about 5% of the electricity they receive into light, with 95% wasted as heat.


Nowadays, incandescent bulbs are being phased out to help protect the environment, with the more energy-efficient alternatives available -


  • CFL (Compact fluorescent) – a flourescent bulb in a coil-like form. They are cost-effective for general lighting purposes, fit directly into the same sockets as incandescent bulbs, and are widely available.
  • LED(Light Emitting Diode) – even more efficient, and a particularly ideal replacement for halogen downlighters. They are more expensive than CFLs but save more money in the long-term.

Any property can save money by fitting energy-saving lights. For example -

  • if you replace an incandescent bulb with a CFL of the same brightness you will typically save around €4 per year, or €70 over the lifespan of the bulb
  • if you replace a 50W halogen downlighter with a 6W LED you will typically save around €5 per year or €90 by the time you need to replace the bulb.


Multiply these figures by the number of standard light bulbs in your house (one survey claims the average EC home has 24) and you'll see the kind of savings you can make.


Penguin offer a fully-qualified service -


  • Advice on energy-efficient lighting
  • New installations
  • Retro-fitting

– call us NOW!





Although CFLs cost more than traditional incandescent bulbs, their much longer lifespan makes them significantly more cost-effective – and LEDs even more so.


Type Hours (average)

Incandescent light bulb 1200

Compact Flourescent (CFL) 9,500

Light Emitting Diode (LED) 50,000




How do they work?


Incandescent light bulbs

A glass bulb with a tungsten filament in a vacuum. Electricity passes through the filament, but only 5% of this produces light. The remaining 95% is lost as heat – extremely inefficient!



Halogen bulbs work much like incandescent bulbs, but filled with halogen gas to help increase their lifespan. As the tungsten filament heats up, it gradually erodes until it burns out. Halogen helps return the tungsten to the filament, allowing the bulb to last around four times longer than a normal incandescent bulb. Halogens were once considered the lighting of the future, but they are far less efficient than CFLs. They also burn hotter than other lights and must be kept at least 6ins/15cm away from flammable materials.


CFLs (Compact Fluorescent Bulbs)

Compact fluorescent lights (CFLs) are a modified version of fluorescent light. The 'bulb' is actually a gas-filled tube, in a coil or spiral, with a 'ballast' which regulates the electrical current. Electricity flows from the ballast and makes the gas within the tube glow with UV light. This in turn excites the white phosphor coating inside the tubing, causing it to emit bright visible light. CFLs are popular as they fit into the same sockets as incandescent bulbs.


LEDs (Light Emitting Diodes)

Light Emitting Diodes (LEDs) contain single diodes of light that combine to form an effective lighting source. LEDs do not get hot like other bulbs, and therefore waste very little energy.




Economic use of lights

To save money on lighting, the most basic solution is obvious: if you don’t need it, turn it off! But here are a few practical tips -

  • Always switch lights off when you leave the room, whatever type of lights you have, and you will save energy by turning them off, even if briefly.
  • You won’t save money by leaving lights on, in an attempt to not 'wear them out'. Just switch them off when not needed, and on again when you do.
  • Have switches where it’s easy to turn lights off. Many houses are wired so you can switch the landing light on/off at both the top and bottom of the stairs. Try to replicate this principle wherever possible, e.g. at both ends of a corridor, or at every door into a room. Otherwise you may be tempted to leave lights on.
  • Use external lights with movement sensors that activate when you approach – these are much cheaper to run.
  • Use the correct lighting for your needs. For watching TV you only need low-level lights, but for reading you need something bright but local.
  • A range of room lights, with separate switches, will make it easier to achieve the lighting you need. And you’ll save more energy than you would by applying a single dimmer switch for them all.


Questions & Answers


Q. Don't energy-saving lightbulbs take a long time to light up?

A. Originally they did, but most modern energy saving bulbs take little more than a couple of seconds to reach full brightness.


Q. Producing an energy-saving bulb must take more energy than making a standard bulb. Doesn't that make it inefficient?

A. An energy-saving bulb may take more energy to produce than a traditional bulb, but the energy saved over its longer lifetime far outweighs this.


Q. Are halogen bulbs more efficient than traditional bulbs?

A. Halogen bulbs are slightly more efficient than traditional bulbs, and most domestic halogens have a lower power rating (typically 20W-50W for halogen bulbs compared with 40W-100W for traditional bulbs). But rooms lit with halogens usually have more fittings than rooms lit with traditional bulbs or energy-saving bulbs. So they will consume more power. To save much more energy, replace halogens with LED lights.


Q. Can energy-saving bulbs have dimmer switches?

A. Most energy-saving bulbs aren't fully compatible with dimmer switch circuits at the moment. However a growing range of dimmable CFLs is emerging to address this problem. There are also energy-saving bulbs that can be used with 'staged dimming', requiring a special sort of dimmer with three simple settings: high, low and off.


Q. Don't CFLs contain mercury? Isn't that bad for the environment?

A. Yes, CFL bulbs contain tiny traces of mercury. However in the long term, they will reduce mercury pollution, because burning fossil fuel such as coal is the biggest source of mercury in the air. Energy-saving bulbs use 80% less electricity than a traditional bulb, which means much less mercury overall.




Some low-energy lightbulbs claim on their packaging to be "100 watt equivalent" but, disappointingly, are nothing like as bright. This is because the 100W figure is only a comparison against electricity consumption and NOT brightness.


To find out how bright a light bulb actually is, you need to know the figure that measures its light output – its Lumens figure. Any type of light bulb should nowadays state this figure clearly on the packet.


It's useful to know that per-watt a CFL light bulb will produce more lumens than an incandescent bulb. For example, a 22W CFL puts out the same amount of light as a 100W incandescent.



Colour The sun gives out white light - the kind of light we're used to most of the time. But traditional incandescent bulbs give out a more 'yellow' light. When indoors, our eyes adapt to this and we perceive it as 'white'. But if we then see a genuinely white light source, it looks blue by comparison. We describe this light as 'cold' because we naturally associate blue with cold and red or yellow with warmth.Most low-energy bulbs, whether CFL or LED, are designed to mimic incandscent bulbs and are often described as “warm white” or "soft white". This is usually the preferred option for general household use. Bulbs that are sold as “cool white” or “pure white” are likely to look less attractive in the home, but may be more appropriate for workplace scenarios or anywhere where clarity rather than ambience is the priority. "Daylight" bulbs are the whitest of all, and are usually only used by artists and others who need to match colours correctly. 
Colour renderingThis is slightly different from colour. Two light bulbs may both give out white light, but one may not show up colours as well as the other. The poorer of the two is said to have a lower 'Colour Rendering Index' (CRI).Standard incandescent light bulbs have a CRI of 100, whilst a good compact flourescent bulb (CFL) will have a CRI of 80 or more, but this is good enough for normal domestic use. Most LEDs have a CRI of 90 or more, so are usually fine. However, if you buy bulbs with a CRI of less than 80 there is a risk that the quality of light will look a little 'flat'.A light bulb's CRI value should be stated somewhere on its packaging.  


Fluorescent lights require ballasts to work. A ballast is a device that regulates the electricity used by the bulb. There are a couple of types of ballasts you can choose. Electronic ballasts virtually eliminate flicker, operate quietly, and maximize energy efficiency. Magnetic ballasts flicker 120 times every second, which may bother some people.

When you replace fluorescent lights, it is important that the light and ballast are compatible in voltage and current, so be sure to match the right tubes with your ballast.


The EU light bulb ban - The Facts

The European Union passed a directive banning incandescent light bulbs, the first stage of which came into effect on 1st Sept 2009. The Directive includes several exceptions but basically means that virtually all incandescent frosted bulbs were banned from that time, and clear bulbs which are not category C rated (or better) were to be phased out over four years. It's not illegal to sell or use existing stocks of these items but, as the bulbs are no longer being manufactured, availability is now extremely limited.

Frosted Bulbs
Any bulb with a frosted, opal, pearl or other opaque finish - unless they are category A energy savers - has been banned from being manufactured since 1st September 2009.

Clear Bulbs
Recognising that it is more difficult to replace clear bulbs with energy-saving alternatives, the Directive provided for these not to be banned outright. Instead, a phasing-out of the least efficient bulbs was scheduled, as follows:


  • All clear bulbs must be category E or better from 1st September 2009
  • 100W bulbs and above must be category C or better from 1st September 2009
  • 75W bulbs and above must be category C or better from 1st September 2010
  • 60W bulbs and above must be category C or better from 1st September 2011
  • All clear bulbs must be category C or better from 1st September 2012


Global benefits of energy-saving lighting


"20 percent of the world's electricity is used for lighting. Three-quarters of that can be saved by using LEDs, i.e. 15 per cent of today's electricity consumption can be saved"

Roland Haitz, former chief technology officer, semiconductor products group, Hewlett-Packard.



"The overall cost of 10,000 hours of light from incandescent light bulbs is 85 euros, but for CFLs is 25 euros, because they use much less energy, and because you might buy only one CFL for every 10 incandescents"

Paul Waide, senior policy analyst with the International Energy Agency (IEA)