Energy efficiency and study-promoting light at secondary schools

Can ambient light make pupils feel and perform better in school? And can LED lighting provide better light with lower energy consumption? This was the basis of the study which was carried out at a secondary school in Helsingborg over six months in In collaboration with Lund University.

The study included 72 pupils aged from 17–18 and was carried out in two different types of classrooms.

The first type was equipped with one of the best school lighting systems on the market: nine T5 luminaires with direct/indirect light mounted in three rows, and board lighting.


The test classroom was instead equipped with newly-developed LED lighting based solely on indirect light directed at walls and the ceiling. The classroom with T5 luminaires had ambient light of approx. 330 lux. 

The classroom with LED had ambient light of approx. 440 lux. Just like in previous studies, the standard was followed with 500 lux on the calculation plane, i.e. the work surface. 

The pupils were followed up three times a day using interviews and cortisol measurements. 

The Indira LED lighting was superior to the T5 solution

The results showed that the LED lighting was superior to the T5 solution, and it was interesting that the pupils were highly concordant in their responses. Pupils in the LED classroom felt more alert in general and particularly until lunch time, and this level of alertness was maintained throughout the school day. Activity levels decreased gradually throughout the day with the T5 solution.

When it came to working conditions in the classroom (visually), the pupils in the LED classroom gave the lighting a very respectable 6 on a scale of 7, while the pupils in the T5 classroom stayed around the 5.6 mark. The pupils in the LED classroom also found the room lighter and thought the lighting quality was better. This is also confirmed by the cortisol measurements and by the pupils’ subjective sense of increased alertness.

The LED room reduced energy consumption and seemed brighter

What is interesting about this is that the energy consumption in the LED classroom was also significantly lower than in the T5 classroom. The result shows that the LED room is 34% brighter within the ambient area, with 13% less energy consumption. The LED classroom used 8 W/m2, compared to 9.5 W/m2 for the T5 classroom. In terms of the Swedish guidelines for “must” and “should” requirements of 12 W/m2 and 10 W/m2 respectively, this refers to an energy saving of 33% and 20% respectively. 

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