PMV Comfort Calculator

Use this component to calculate comfort metrics of Predicted Mean Vote (PMV), the Percent of People Dissatisfied (PPD), and the Standard Effective Temperature (SET) for a set of climate conditions and occupant behavior/clothing.
This component can also calculate Outdoor Standard Effective Temperature (OUT-SET) if EPW weather data is connected. HOWEVER, if you are interested in knowing whether outdoor conditions are actually comfortable, it is highly recommended that you use the Ladybug UTCI Comfort Calculator. OUT-SET has been shown to be a poor indicator of outdoor comfort and is better used as a tool to help understand what clothing and metabolic rate a comfortable person might have in the outdoors AFTER running a UTCI study.
Predicted Mean Vote (PMV) is a seven-point scale of occupant comfort from cold (-3) to hot (+3) that was used in the comfort surveys of P.O. Fanger, who initially developed the scale and the PMV comfort model off of it. Each interger value of the PMV scale indicates the following: -3:Cold, -2:Cool, -1:Slightly Cool, 0:Neutral, +1:Slightly Warm, +2:Warm, +3:Hot. The range of comfort is generally accepted as a PMV between -1 and +1. Exceeding +1 will result in an uncomfortably warm occupant while dropping below -1 will result in an uncomfortably cool occupant. PMV is a MEAN vote because is meant to represent the average vote of all people under the input conditions.
This component will output the PMV of the occupant for the input conditions as well as an estimated Percentage of People Dissatisfied (PPD) under the given conditions. PPD refers to the perceont of people that would give a PMV greater than/equal to 1 or less than/equal to -1. Note that, with this model, it is not possible to get a PPD of 0% and most engineers just aim to have a PPD below 20% when designing a HVAC system.
This component will also output Standard Effective Temperature (SET), which is an ajusted temperature scale meant to reflect the heat stress or cold felt by the occupant. Specifically, SET is definied as the equivalent temperature of an imaginary environment at 50% relative humidity, <0.1 m/s air speed, and mean radiant temperature equal to air temperature, in which the total heat loss from the skin of an imaginary occupant is the same as that from a person existing under the input conditions. It is also important to note that the imaginary occupant is modeled with an activity level of 1.0 met and a clothing level of 0.6 clo. The actual occupant in the real environment can have different values from these.
The original PMV studies by Fanger involved placing subjects in an air conditioned climate chamber for an hour in which the subjects had no means to adjust their conditions to make them comfortable. Subjects where then asked to pick an interger on the PMV scale. Since PMV subjects could not change their layers of clothing or open windows to make themselves comfortable, the PMV model is most useful when applied to these conditions of an air conditioned building in which users cannot open windows, turn on fans or change dress code. For comfort in conditions where people can adjust these factors, the adaptive comfort calculator or UTCI comfort calculator would be most useful.
The comfort models that make this component possible were translated to python from a series of validated javascript comfort models coded at the Berkely Center for the Built Environment (CBE). The PMV model used by both the CBE Tool and this component was originally published in ASHARAE 55.
Special thanks goes to the authors of the online CBE Thermal Comfort Tool who first coded the javascript comfort models: Hoyt Tyler, Schiavon Stefano, Piccioli Alberto, Moon Dustin, and Steinfeld Kyle. http://cbe.berkeley.edu/comforttool/

Inputs

Outputs

Video Tutorials