Lighting is another area where there is potential to save energy and cost.

The first thing you need to do is check what kinds of lamps and fittings you have, and how many of which. You also need to look at the area you are lighting, how long lights are on, what is the occupancy rate of the area, what level and colour of light you need, and any special requirements -

How long lights are on during the week obviously makes quite a difference to the amount of money to be saved by having more energy efficient lighting. Occupancy can be a different issue - lights will often be on in unoccupied areas, either because they cannot be switched off separately from occupied areas, or because they are simply left on.

Upgrading light fittings and lamps

If your premises has old-style one and a half inch (T12) or 1 inch (T8) fluorescent tubes that start on mains frequency (they flicker when you turn them on), there are good potential savings by converting to T5 tubes with high frequency ballasts. There is an initial investment, but you can save as much as 45% off the lighting bill, although lighting levels may be reduced if you want to achieve this level of saving.

There are two options to choose from when doing this - completely replacing the fittings, or using a conversion kit.

If the lighting fittings are more than 10 years old, the Carbon Trust recommend that replacing them is likely to be more cost effective than conversions. They also do not recommend conversion kits if you already have high frequency ballasts, as most of the saving is in changing to these.

Conversion kits come in two forms, and are available for most lengths of tube - although not for 8 foot fittings.

The first type provides new tube ends, to fit over a T5 tube, and a replacement starter. The second type is a kit that slots into the existing fitting; the T5 tube then fits into that.

The Carbon Trust have a downloadable pdf giving information about these on their website -  How to implement T5 retrofit conversion kits (CTL028). The website also has lots of information about what types of lighting are most suited to where, and a calculator to help give you an idea of how much you can save.

Adding controls

New controls can also save money, whether changing how lights are manually operated or by introducing automatic sensors.

In a factory with night shifts, but good lighting in the day - perhaps from skylights in the roof - lights will often stay on all day, simply because no one thinks to turn them off as it gets lighter. Automatic light sensors can detect this and then control the lighting level as needed - dimming or brightening the lights according to the level of ambient light. If you have large areas of window, using light sensors on the lights nearest to the window can help there too - those lights can often not be needed while lights in the rest of the area still are.

Light sensors are particularly useful for outside lights. Although these are often on timers, it is very easy to forget to change the timer as the day lengthens, and so to waste money.

In areas with little occupancy - storage areas and meeting rooms, for example, movement sensors can be a good idea, saving people from having to remember to turn lights off. Or you can use combined sensors in areas where artificial lighting is not always necessary.

Sensors can either control a whole bank of lights, or be incorporated into individual fittings.

See the Carbon Trust How to implement automatic lighting controls (CTL033) for more information about the different types of controls and an idea of costs and savings. Automatic controls like this come under the UK Government Enhanced Capital Allowance scheme, and there is a list of approved control mechanisms on their website www.eca.gov.uk

Manual controls may also benefit from a review and changes if the switches operate large banks of lights. Again, having separate controls for banks of lights nearer the windows and for little-used areas can reduce the number of unnecessary lights left on simply because it's all or nothing.