RefurbN16

Tag: Lighting

  • Energy Efficient Lighting Pt 2 – Halogens

    The first post on lighting took a look at CFLs, the cheap and effective replacement for standard incandescent lamps*, but over the last couple of decades, many homeowners have opted for halogen lighting.

    Halogen lamps are incandescent i.e. electricity passes through a tungsten filament which heats up and emits light. They differ from the standard incandescent bulbs in that the filament is encased in a capsule full of halogen gas which reacts with the filament in a process called the halogen cycle.

    Halogen lamps have a higher efficacy than standard incandescent lamps, but you generally need quite a lot of halogens to light a room so you usually end up using a fair bit more electricity for the same effect. Now, with electricity prices high and rising, what can be done to reduce the electricity consumption from all those halogens?

    The cheapest option to cut electricity consumption from halogen lighting is to buy a batch of energy saving halogen lamps. These cost a bit more than the normal ones but use about 30% less electricity and they usually last a bit longer too.

    You can also buy halogen replacement CFLs. These are little compact fluorescent lamps that are folded up into a halogen-sized fitting. They’re not cheap (anywhere between £10 and £20 each for a good quality lamp) but they are a lot more efficient than the energy saving halogens and should last a lot longer.

    If you have your halogen lights on a dimmer system, be careful as CFLs often can’t handle this, and as with all CFLs you want to make sure that you get one with the kind of light output that you feel comfortable with. Check this post to see what to look for.

    Finally there is also the LED (light emitting diode) option.  LED lighting is much more efficient than incandescent lighting and LED lamps have much longer lifetimes (at least the quoted lifetimes are much longer, actual lifetimes remain to be seen).

    The main barrier to the widespread uptake of LED lighting now is cost. Good quality LED fittings are still eye wateringly expensive (around £20 to £40 each) but as they’re so efficient and as they should last tens of thousands of hours, they do pay for themselves many times over in energy savings and replacement costs over their lifetime.

    I’ll go into more detail on LED lamps in a future post, but briefly, the technology has moved on a lot in the last few years and you can now buy really good quality lamps.

    Prices will come down in the next few years so it might be worth holding off for a little while, but if you are going to be redoing the interior of your house and you currently have halogens, it’s probably a good time to consider this technology.

    Useful tip: if you are considering investing in these more expensive halogen replacement options, then the best tactic is to replace the bulbs that have the highest use first. By replacing these bulbs you will see the biggest drop in your electricity consumption and they will pay for themselves in the shortest time.

    * A lamp is what is more commonly referred to by people outside the industry as a bulb. What we normally call a lamp would be called a luminaire in the industry.

  • Sustainable Refurbishment – Towards an 80% Reduction in CO2 Emissions

    The UK’s building regulations didn’t start to consider energy consumption until the 1960s, when very basic requirements to conserve energy were placed on house builders. These requirements have slowly been tightened over the decades and the introduction of the Code for Sustainable Homes has accelerated this in recent years.

    The intention is that new build homes built from 2016 will be zero carbon (although the exact definition of ‘zero carbon’ in this case is still up for grabs). The problem is that the UK’s housing stock is the oldest in the developed world, with 8.5 million properties over 60 years old and an estimated 24 million homes built up to 2016 expected to still exist in 2050.

    Zero carbon new build homes are definitely needed so that new homes don’t add to emissions, but all of the carbon reductions will have to happen in homes that have already been built.

    In the previous post we looked generally at a whole house approach to sustainable refurbishment. The Energy Saving Trust has recently published an interesting new publication which looks at this in more detail and points the way towards an 80% reduction in CO2 emissions in existing homes. This guide is aimed at homeowners as well as housing developers and builders and is clearly written and nicely presented.

    It gives an excellent overview of the energy efficiency measures that can be implemented in the UK’s homes including the different types of wall, roof and floor insulation, improving windows and doors, increasing air tightness as well as efficient heating and hot water systems and lighting and appliances. Also covered are microgeneration, water efficiency, waste and recycling and even climate change adaptation.

    If you want to get a good picture of what needs to be done to our homes, then this is a good starting point. Hopefully it will stimulate you to consider which of these measures can be applied in your home.

    The Energy Saving Trust has lots of interesting technical guidance. More information can be found here.

  • Energy Efficient Lighting Pt 1 – CFLs

    The widespread roll out of compact fluorescent lamps (CFLs) has caused quite a stir to say the least – these innocuous little things have upset quite a lot of people, with some feeling the need to take drastic action.

    Certain sections of the press definitely haven’t helped, spreading some pretty extraordinary stories about CFLs over the last few years; stories which have been designed to spread confusion and fear of what is a very good and safe energy efficiency technology.

    People have been working under fluorescent lighting for decades and a CFL is not very different to an office fluorescent tube – it’s just been folded up on itself into a much smaller space.

    That’s not to say that they’re without fault. They contain a very small but significant amount of mercury and therefore need to be handled appropriately (more on that in a future post), in some cases they can take a moment to warm up which is not what we’re used to after a century of incandescent lighting and the light that some give out is not the best.

    Another problem is that a lot of unsolicited bulbs of varying quality have been distributed under the Carbon Emissions Reduction Target, with people receiving bulbs through the post with the wrong fitting, bulbs that give out a harsh light and bulbs that looked, well… pretty damned ugly.

    But it definitely doesn’t have to be like this so this post is dedicated to the things to look out for when hunting for the perfect CFL.

    CFLs use about a quarter of the electricity of a conventional incandescent. This is a big saving and one that means that you shouldn’t wait until an incandescent bulb blows before replacing it.

    The embodied energy of a CFL (the energy used to produce it) is greater than the embodied energy of an incandescent bulb, but the efficiency savings you get from using CFLs greatly outweighs this additional energy so swap all your remaining incandescent bulbs today.

    Defra has published a comprehensive life cycle assessment of ultra efficient lamps which is worth reading if you want to know more about the environmental impacts of different lighting technologies.

    You can pick up very cheap (often subsidised) CFLs all over the place nowadays but I find it’s worth spending a few pounds on really good quality bulbs. On average a CFL will save a few pounds each per year and if it’s replacing a high use bulb it’ll save you a good deal more than that and over the lifetime of the bulb they will save you anywhere between £50 and £100 per lamp.

    In different situations you might be looking for different qualities in your CFL. For example on an upstairs landing you might want one that warms up quickly, in the living room you might want a warmer light while in the kitchen you might want a bluer and brighter light.  As these types of bulbs last for a good 10,000 hours, it’s worth finding the right one for your needs.

    The thing that many people seem to object to most is the colour of light that CFLs give out, known as the Colour Temperature.

    You can buy fluorescent lamps in a range of colour temperatures from 4000K (or 4000 Kelvin, sometimes known as “cool white”) which gives a stark, blue light, to 2700K (sometimes known as “warm white”) which gives a much warmer colour very similar to incandescent bulbs. Natural daylight is very blue and has a colour temperature of about 6500K.

    For most people this lower colour temperature (which confusingly gives a “warmer” colour) is what they should be seeking out.

    Another measure of the quality of light which a bulb gives out is the Colour Rendering Index. This measures how faithfully the colour of  a surface appears under different light sources compared with an ideal light source.

    The scale measures up to 100 and the higher the CRI the better. You can buy CFLs with a CRI of over 80.

    Efficacy is a measure of how efficiently it converts electricity into light and is measured in Lumens per Watt (Lm/W). You will sometimes see CFLs with the same power consumption but different Lumen output (i.e. one is brighter) and this is an example where one lamp has a higher efficacy than the other.

    The use of Watts to describe a bulb’s brightness is being phased out at the moment and you’re going to be reading a lot more about Lumens in the future (both will be displayed on packaging). It makes a lot more sense to use Lumens as this is a measure of brightness whereas Watts are a measure of power consumption.

    The following table gives the brightness that incandescent lamps of different power give so you can work out what brightness a replacement CFL should be.

    The “clear” column gives the brightness of incandescent bulbs made with clear glass and the “soft” column is the brightness for the frosted sort of bulb:

    Power (W) “Soft” Brightness (Lm) Clear Brightness (Lm)
    40 335 365
    60 575 620
    80 830 895
    100 1075 1175

    (Source: EST Lighting Specification)

    In common with all lights, including incandescent bulbs, CFLs lose some brightness over their lifetime, but if you buy a good quality bulb they will give a good light output for a very long time.

    A bulb’s start up time is also important for many people. CFLs switch on very quickly (less than a second) but then take a while to run up to full brightness. They can take up to a minute or so to reach their maximum brightness, but what is most important is how quickly they get up to a reasonable brightness.

    If start up time is important to you then look for “fast start” bulbs that warm up quicker than regular bulbs. In some cases I find it’s nice to have a slow warm up time, especially in bedside lights so that you’re not blinded in the middle of the night.

    So that introduces the technical aspects to look for. Size and shape should also be considered as some CFLs won’t fit as neatly in a lampshade as others but there is now such a huge range out there that you can find excellent bulbs for nearly every situation and the number of good quality bulbs is growing all the time.

    For the record, my favourite CFLs are made by Megaman but there are a load of good ones out there. At some point I might do a post collecting together the best bulbs from each manufacturer. Feel free to post your favourites in the comments below.

    In future posts we’ll look at other aspects of lighting such as halogens, what to do if you have dimmer switches and other technologies such as LEDs.

    Power (W) “Soft” Equivalent Clear Equivalent
    40 335 365
    60 575 620
    80 830 895
    100 1075 1175