Predicted Mean Vote (PMV) is a thermal comfort index defined in ASHRAE Standard 55 (Thermal Environmental Conditions for Human Occupancy).
It predicts the mean value of votes from a large group of people on a seven-point thermal sensation scale, which ranges from cold (-3) to hot (+3).
The PMV model is based on the Fanger Comfort Equation, which accounts for factors influencing thermal comfort such as:

1.  Air Temperature: The temperature of the surrounding air.
2.  Mean Radiant Temperature: The average temperature of
3. surrounding surfaces.
4. 3. Relative Humidity: The amount of moisture in the air.
5. 4. Air Velocity: The speed at which air moves around the
6. body.
7. 5. Clothing Insulation (Clo): The thermal insulation
8. provided by clothing.
9. 6. Metabolic Rate (Met): The rate of metabolic heat
10. production due to activity level.

The PMV scale is defined as: +3: Hot, +2: Warm, +1: Slightly warm, 0: Neutral, -1: Slightly cool, -2: Cool, -3: Cold.

Practical Use in ASHRAE 55

According to ASHRAE 55, the comfortable PMV range is typically between -0.5 and +0.5. In this range, the majority of occupants are
expected to feel thermally neutral or only slightly uncomfortable.

 In practice, achieving thermal comfort involves controlling indoor environmental conditions such as temperature, air movement, humidity,
and clothing level to maintain PMV within the acceptable range.

Section J1V3 performance assessment

The method is part of the NCC or BCA Section J1V3 performance assessment with a reference building. 

Note that the Section J1V3 performance assessment, part of the National Construction Code (NCC) or Building Code of Australia (BCA), is a method used to evaluate a building’s energy efficiency. It involves comparing the proposed building’s energy performance against that of a reference building, which is a notional building designed to meet the minimum Deemed-to-Satisfy (DtS) provisions of Section J. The reference building is constructed virtually with the same size, shape, and function as the proposed building but uses standard energy efficiency measures. By simulating both buildings under identical conditions, the Section J1V3 method assesses whether the proposed building’s design performs equally or better than the reference building in terms of energy consumption and compliance with the NABERS energy performance standards in the NCC. This method allows for design flexibility while ensuring energy efficiency objectives are met.