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Funding - case Study

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An office in Reading is almost exclusively lit by T8 4ft tubes, with160 light fittings in total. The distribution of light is inadequate and the running costs are high.

A model is produced to model an improved light distribution, with a target maintained light level (achievable after 10 years of degradation) on the horizontal desk surfaces of 500 lux.

The lights are replaced by 260 40W 600m x 600m LED Panels at a cost of £16,040 + VAT.  

The running load is reduced from 28kW to 10.4kW, resulting in a 63% reduction in running costs, and annual savings of £5,530.  

The investment payback time is just under 3 years.


  Existing lights Proposed LEDs
Max load (kW) 28 10.4
Total no of fittings 160 260
Average running hours per annum 2890 2850
kWh consumption per annum 80,920 29,640
Savings   Proposed LEDs
kWh reduction per annum   51,280
As a % of current usage   63%
Running cost reduction @ 10.5p per kWh   £5384
Maintenance cost reduction per annum   £146
 Total savings per annum    £5,530
Cost of upgrade (ex VAT)   £16,040
Payback time   2.9 years
Reduction in carbon footprint    
CO2 reduction per annum   27.6 tonnes


Lease Financing

For this project, four year lease financing is available at a cost of 8.0%, with payments of £4840 per annum. These are more than covered by the savings made in running costs. The full cash flow is set out below.