What is PMV and PPD in thermal comfort?

PMV (Predicted Mean Vote) predicts average thermal sensation on a scale from -3 (cold) to +3 (hot), with 0 being neutral. PPD (Predicted Percentage of Dissatisfied) shows the percentage of people likely uncomfortable, minimum 5% even at optimal conditions.

What are acceptable PMV and PPD values?

ASHRAE 55 recommends PMV between -0.5 and +0.5, corresponding to less than 10% PPD. ISO 7730 Class A requires PPD < 6%, Class B < 10%, Class C < 15%. Most commercial buildings target Class B conditions.

What factors affect thermal comfort?

Six factors: four environmental (air temperature, radiant temperature, air velocity, humidity) and two personal (metabolic rate from activity, clothing insulation). The calculator uses the Fanger model to combine all factors.

How does clothing affect PMV?

Clothing insulation is measured in 'clo' units. Light summer clothes ≈ 0.5 clo, typical business attire ≈ 1.0 clo, heavy winter clothes ≈ 1.5 clo. Higher clo values shift comfort zone to lower temperatures.

What is metabolic rate and how do I estimate it?

Metabolic rate measures body heat production in 'met' units. Seated quietly = 1.0 met, light office work = 1.2 met, walking = 2.0 met, heavy labor = 3-4 met. Higher activity requires cooler environments.

Why can't everyone be satisfied with thermal conditions?

Individual comfort preferences vary due to physiology, acclimation, and psychology. Even at 'optimal' PMV=0, about 5% will be dissatisfied. The goal is to minimize dissatisfaction, not eliminate it entirely.

PMV/PPD Thermal Comfort Calculator

ASHRAE 55-2020ISO 7730Fanger Model

ASHRAE 55-2020ISO 7730

Thermal Comfort Calculator

Enter environmental and personal factors to calculate thermal comfort indices

Frequently Asked Questions

Common questions about this calculator

PMV/PPD Thermal Comfort Calculator

Environmental Conditions

Personal Factors

Frequently Asked Questions

PMV/PPD Thermal Comfort Calculator

Environmental Conditions

Personal Factors

Frequently Asked Questions

01What is PMV and PPD in thermal comfort?

02What are acceptable PMV and PPD values?

03What factors affect thermal comfort?

04How does clothing affect PMV?

05What is metabolic rate and how do I estimate it?

06Why can't everyone be satisfied with thermal conditions?