What is a comfortable office temperature – and why this is very important when it comes to reducing carbon emissions

Changes to temperature settings are a little known but easy way of getting significant carbon savings in offices.

In office buildings the single largest energy user is the heating, cooling and ventilation system. This system will typically account for 40% to 60% of the buildings energy cost and greenhouse gas emissions. A major determinant of how much energy your system uses is the temperature at which it is set to operate. Depending on climate, most offices are set to maintain a year round temperature of either 22OC or 24OC.

Hobsons Bay City Council in Melbourne had temperature settings at the Hobsons Bay Civic Centre adjusted by CarbonetiX engineer Linton Hartfield to allow the temperature to vary between 20 and 25 degrees Celcius. Electricity metering of the air conditioning system showed a 25% energy saving on the packaged heat pump units supplying the building. The air conditioning temperature changes occurred a couple of months after a building extension – which had increased electricity consumption by 10%. According to Environment Officer Rowena Joske, “After the temperature adjustments the electricity bills dropped back to what they were before the extension.” In other words simply adjusting the temperature settings has cut carbon emission by 10%.

Temperature complaints are, however, a major bane to facility managers who can’t seem to keep everyone happy. Do adjustments to temperature settings increase the number of complaints? In the case above more complaints did occur about it getting above 25 degrees in some parts of the building. So the system has been adjusted back in those parts of the building to limit the maximum temperature to no more than 25 degrees.

Comcare, a federal government organisation for public sector employees, has produced guidelines as to what a comfortable office temperature is. According to Comcare the acceptable range of office temperatures is 20 to 26 degrees Celcius, with 20 to 24 degrees recommended in winter and 22 to 26 degrees recommended in summer.

In temperate and cold climates in Australia allowing the temperature in the office to float between 20 to 24 or 25 degrees will significantly cut energy use and carbon emissions as compared to setting the system to maintain exactly 22 degrees. In hotter climates allowing the temperature to go up to 26 degrees instead of making it stay at 24 degrees will similarly save energy and carbon emissions.

For offices in terms of carbon reduction per dollar spent it doesn’t get much better than changing building temperature settings.