Improving Indoor Air Quality – Integrating productivity and comfort

The range of thermal comfort that is neutrally acceptable without health impact has been proposed as running between 17°C as the lowest and 31°C as the highest acceptable temperature. (Weihe 1987, World Health Organization 1990).

How to measure thermal comfort in a kitchen

use a thermal mannequin
measure skin temperature and the power needed to maintain temperature
calculate the mean thermal at 25 body locations

See presentation on thermal comfort measurements here.

If the air temperature is maintained at 27 °C in the kitchen, employee productivity falls to 80 %. See the table of productivity loss in warm working areas: productivity / temperature.

How productivity can increase profits

Labour shortages are the greatest challenge that commercial restaurants face today. The average age of a restaurant worker is between 16 and 24 years. In a recent survey conducted by the National Restaurant Association in the USA, more than 52 % of respondents said that finding qualified motivated labour was their main concern.

In a restaurant with an annual turnover of EUR 1,500,000:

Typical profit could be EUR 75,000 (5%)
Salary costs could be at the level of EUR 250,000
Productivity loss of 30% (the room's temperature is 6 °C above the thermally neutral level) means EUR 75,000 in annual losses in the workers' productivity
In addition, an improved working environment decreases absenteeism and employee turnover, also reducing recruitment fees.

Studies

Fisk (97/98): respiratory infection cases cost 6 -14 billion US dollars per year, allergies and asthma $2 - 4 billion, 'sick building syndrome' $15-38 billion, and related work efficiency losses $20-200 billion

Seppänen (99): poor indoor climate in Finland costs 2.7 billion euros annually

Wyon (96): cost/benefit analyses that assume an impact on productivity of 0.5% have shown that the payback time is 1.6 years

The Dutch government (UWV department 2002): work disability numbers vary by profession: the highest numbers are for catering then butcher's work, rubbish collection, and construction work

Wargocki (99): in simulated office work, an extra pollution load (20-year-old used carpet) increased the percentage of dissatisfaction from 15% to 22% and decreased the amount of typing by 6.5%

Wyon (96): The building code target can satisfy only 80% of people while individual control equivalent to +/- 3 °C would satisfy 99% of employees and improve productivity 5 - 15 %

Schweisheimer (66): in industry, the average performance of workers dropped by 10% at 30 °C, by 22% at 32 °C, and by 38% at 35 °C.