As part of a project to make lighting more efficient the National Trust wanted to switch from power-hungry 70W CDMT lighting to a new energy efficient LED solution.

The project was a retro-fit using an existing CDMT track lighting system, and Liet Bar LEDs fitted within a surface mounted fluorescent tube system.

The project objectives were to achieve 600 lux in the entranceways and create a relaxing ambience in the café and breakout areas, whilst achieving a significant reduction in energy, lamp and FM costs.

Our lighting designers produced the lighting schemes to include Liet D-Series, as the best LED for this application. We worked closely with the National Trust to ensure that beam angle, colour temperature and lighting control matched the incumbent CDMT technology.

The new LED lamps retro-fitted perfectly with existing luminaires and offered a long-lasting alternative to the legacy CDMT technology.

As well as consulting in the early planning stages, Lietcorp offered a full LED lighting package including support and training to the client’s electrical installer.


Project images


49 No. 70W CDMT lamps and 44 No. 38W 4ft T8 tubes were replaced by the following LED light engines:

– Liet D35: 18W, 4,000K, 36 degree, 90,000 hour L70 life

– Liet Bar: 6W, 4,000K, 160 degree, 90,000 hour L70 life

Energy savings

– Annual operating cost (electricity, lamp & FM) before LED £4,151

– Annual operating cost (electricity, lamp & FM) after LED £679

– Annual cost saving £3,472

– Annual carbon reduction 11 tonnes

– Payback (after ECA) 2.3 years

– CAPEX Required £10,000

– Capitalised over 5 years total profit uplift £7,360

Note: all payback and saving calculations exclude: 1) any facilities management savings associated with call-out charges to change lamps 2) air conditioning savings associated with the low heat of Lietcorp’s LED lighting

Website design and branding | Cubic