Lighting uses a lot of electricity. For some workplaces, such as offices and shops, it can account for as much half of total electricity bills.
How much is your lighting costing you?
Unless your buildings have sub-metering of lighting or other circuits, it will not be immediately clear how much electricity you are using for lighting and its true cost impact. And that can make it hard to get your colleagues onboard with improvement projects.
Two ways of assessing how much your lighting is actually costing your organisation and, therefore, how much effort you and your management team should put into this area, are the top-down and bottom-up approaches.
The top-down approach looks at total electricity use and then estimates the percentage that is used for lighting. Of course, this proportion will vary greatly depending on whether electricity is also used as the fuel for space and water heating. So, for a gas-heated office without air-conditioning, lighting typically accounts for 50% of electricity use. The remainder will be accounted for by office equipment, kettles and other small appliances.
In the bottom-up approach, the number of each type of lamp you use is determined. This figure is then multiplied by the wattage of each type of lamp and the hours of operation. This will give the total lighting energy used in kilowatt hours (kWh). You can then work out how much your lighting costs by multiplying the energy used by the price you pay per kWh.
Figure 1 shows that a small single-shift factory operating 9 hours per day, 50 weeks of the year with 40 T8 58W fluorescent lamps and 20 50W halogen lamps in its reception and offices would use 7,470kWh of electricity per year on lighting, costing nearly £1,000.
If you would like to use the bottom-up approach to assess how much your lighting is costing your organisation, please download and use our simple lighting costs calculator spreadsheet.
Further support
If you are a Scottish SME, Business Energy Scotland is here to provide you with free and impartial support and access to funding to help your workplace advantage of all the latest lighting technology.
We have a team of experienced advisors that has already helped hundreds of organisations across Scotland improve their lighting and reduce associated energy costs. Some examples include:
- The Water of Leith Visitor Centre in Edinburgh has almost halved its energy bill
- Kelvinside Electronics in Kilsyth is already saving over £8,750 a year
- Cambuslang-based BookSource has slashed its annual bill by over £16,000
- Scottish retailers, The Village Store and Goldenacre Mini Market, have saved by upgrading their lighting
Get support today and we’ll write a detailed report showing you how much you could save too.