IMPORTANT - This version of the tool (v2.0.0) complies with the ASHRAE 55 2017 Standard. This version is no longer supported and may contain errors that have been fixed in newer releases. Please visit the CHANGELOG page to find out more.

CBE Thermal Comfort Tool for ASHRAE-55
Inputs
°C
m/s
%
Outdoor air temperature (6 am) °C
PMV =
PPD = %
Sensation =
SET = °C
Dry-bulb temperature at still air = °C
Cooling effect = °C
NOTE: In this psychrometric chart the abscissa is the dry-bulb temperature, and the mean radiant temperature (MRT) is fixed, controlled by the inputbox. Each point on the chart has the same MRT, which defines the comfort zone boundary. In this way you can see how changes in MRT affect thermal comfort. You can also still use the operative temperature button, yet each point will have the same MRT.
Limits of Applicability: This standard is only applicable to healthy men and women. This standard does not apply to occupant: a) whose clothing insulation exceed 1.5 clo; b) whose clothing is highly impermeable; or c) who are sleeping, reclining in contact with bedding, or able to adjust blankets or bedding.
NOTE: In this psychrometric chart the abscissa is the operative temperature and for each point dry-bulb temperature equals mean radiant temperature (DBT = MRT). The comfort zone represents the combination of conditions with the same DBT and MRT for which the PMV is between -0.5 and +0.5, according to the standard.
Limits of Applicability: This standard is only applicable to healthy men and women. This standard does not apply to occupant: a) whose clothing insulation exceed 1.5 clo; b) whose clothing is highly impermeable; or c) who are sleeping, reclining in contact with bedding, or able to adjust blankets or bedding.
NOTE: This chart represents only two variables, dry-bulb temperature and relative humidity. The PMV calculations are still based on all the psychrometric variables, but the visualization becomes easier to understand.
NOTE: This chart represents only two variables, air speed against operative temperature. The operative temperature for each point is determined by dry-bulb temperature equals mean radiant temperature (DBT = MRT). The calculation of PMV comfort zone is based on all the psychrometric variables, with PMV values between -0.5 and +0.5 according to the standard.
Limits of Applicability: The elevated air speed comfort zone method is to all spaces where the occupants have activity levels between 1.0 and 2.0 met and clothing insulation between 0.0 and 1.5 clo. There is no upper limit to air speed if occupant's total clothing > 0.7 clo and metabolic rate > 1.3 met.