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What do we know about good levels?

This is complex. The algorithm of good learning has many components, even when we just focus on the physical environment. Those components overlap - and the interrelationships between them are not simple. Also the graph from "poor ---> better" is rarely a straight line: too loud is a lot worse than too quiet for example.

The Learnometer project is putting serious effort into considering that complexity, and simplifying it for users.

However, it is helpful right away to explore easily measured variables like sound and light. Children build their own reflective practice as a result of this work, and insights can be hugely revealing. Chatting to a teacher where they had done some initial monitoring and measuring his school had been amazed at the correlation between staff absence and use of a room exhibiting very high levels of CO2, whilst exploring children ranked by the extent to which they exceeded, or missed, their predicted performances saw a disproportionately large number of that classroom's users in the bottom decile group. The room was damaging students and teachers alike. And that was just CO2...

Here are some numbers to start you off:

Light: lots of debate about levels in design guidelines for offices, and there are international variations in guidance, and we are not saying anything here about flicker or light quality, or colour, but a good rule of thumb would be:

for conversation, discussion, etc a minimum of 250 lux

for close work - writing, keyboard work, drawing, reading, a minimum of 450, perhaps even 500 lux

for damage - you only have to get to levels around 50 lux or below - and most schools have way too many of these - sometimes examination rooms in particular are too dark - kids and results suffer

Colleagues ask about dark spaces and there are, of course, times when darker is calming but if you are expecting children to read, or work in those spaces, or even to discuss, then think again. Light is good.

For a significant number of children the projector or IWB needs help - daylight washes out the display - and windows are fitted with blinds. This is fatal of course - measure the levels yourslef and see just how bad... A brighter screen is not a brighter learning environment - measure where the children are.


Sound: plenty to read in detail here but two variables to look out for.

Sound above around 72 decibels starts to be disruptive - although what the sound is matters (for example is is hard to write when background music contains a familiar lyric). Even music, by the time is reaches "really too loud" which might be straying into the 90 decibel range, will reduce performance substantially.

But also beats per minute matter and again the simple guide for here is to stay below 60 beats per minute to keep heart rate and blood pressure down.


CO2: teenagers emit fumes from just about every orifice (!) but CO2 is the gas to avoid for learning. Indoor workspaces with good ventilation should be around 350 - 1,000 parts per million. Between 1,000 and 2,000 drowsiness will occur, between 2,000 and 5,000 students will suffer headaches, sleepiness, poor concentration, loss of attention with increased heart rate and slight nausea as we move towards the top of the range. Too many classrooms, and examination / test halls, run at levels in this range, often towards the top or above.


Temperature: again complex. Much early research was around efficient workplace temperatures (for example British Industrial Fatigue Board studies showed increased accidents occurred when air temperature deviated from 20°C (Vernon, 1919, 1927). Other work looked at core body temperature (which depended a bit on activity) or reported comfort (usually that saw a higher figure - folk like to be warmer than they need to be!). One study found that office task performance was slower at 21°C than 24°C, but was fastest at 18°C (!).

Amar Cheema and Vanessa Patrick measured two groups, one at 19°C and one at 24°C. Participants were asked to identify spelling and grammatical errors in an article. The participants in the cooler room identified twice as many errors as those who were in the warm room. In a second study in a similar setting, participants were asked to pick the most beneficial (cost-effective) cell phone plan when given two choices. It was a complex task, but participants in the cooler room picked the right plan half the time where the participants in the warmer room picked the correct plan only a quarter of the time.

All these are observation studies, but as we know more about brain science we see detail emerging, about temperature and brain function, that is revealing. For example, your brain's metabolism generates heat. So brain temperature is also a function of the brain's activity. This is early work though.

For learning the concensus seems to be around the 18°C to 20°C, certainly not higher, and I favour low end of 18°C in active classrooms that have standing work as well as sitting work and movement.

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this page created and last updated on Wednesday, February 4, 2015 11:10 AM