Thermal Comfort Calculator

What is Thermal Comfort?

Thermal comfort is a feeling of well-being experienced when a person is satisfied with the existing environment. Thermal comfort indices measure how the human body temperature reacts to conditions of the environment such as air temperature, relative humidity, and air velocity.

Why is monitoring thermal comfort important? In high-traffic or heat-intensive facilities, maintaining optimal thermal comfort isn't just about comfort; it's a critical component of workplace safety and productivity. Exposure to high temperatures and fluctuating outdoor temperatures can increase the risk of heat stress, making it essential to monitor weather data and environmental conditions. By proactively monitoring and optimizing comfort, facilities can protect employee health, boost morale, reduce turnover and maximize ROI while reducing production setbacks.

Common Questions About Thermal Comfort:

Should I Use the Thermostat Reading or a Measured Ambient Temperature?

This is one of the most common questions we receive. For this calculator, we recommend using your thermostat's temperature setting as a reference point. This value represents the standard air temperature without the influence of moisture and is also referred to as the dry bulb temperature.

What is the Difference Between Dry Bulb and Wet Bulb Temperature?

We have found that these two measurements capture different aspects of air conditions. The dry bulb temperature is the most familiar temperature reading and is the number you set the air temperature to in your space. Dry bulb temperature is measured by standard thermostats. 

Wet bulb temperature, on the other hand, incorporates the effect of moisture and evaporation. 

Our thermal comfort calculator focuses specifically on dry bulb temperature paired with relative humidity to align with ASHRAE thermal comfort models.

What Does 'Estimated Productivity Lost' Mean?

The estimated productivity loss shown in our calculator reflects the potential decrease in work output that may occur due to thermal discomfort. Using our 15 years of experience and modeling standards, we estimate how rising temperatures and humidity reduce performance. As indoor environments move into the “warm,” “hot,” or “dangerously hot” ranges, occupants may experience slower reaction times, increased fatigue, and more frequent breaks. 

To what level does reduced performance affect your bottom line? These slowdowns lead to measurable reductions in productivity. Even a 2-5% drop in productivity over a sustained period can lead to substantial financial impacts, especially in labor-intensive industries. For a 50-person warehouse team, that could equate to hundreds of lost hours each month.

What is the best way to reduce production setbacks? Based on the immediate, positive effects reported from our commercial and industrial customers, our recommended strategy is to install a commercial or industrial ceiling fan. Looking for a recommendation? One of our Product Specialists can work with you to understand the requirements of the space and make the proper fan recommendation. Our team can design a fan layout plan, ensuring maximum improvement from your investment. 

What Can I Do if My Facility Scores Poorly on Comfort?

Based on feedback from our commercial and industrial customers, if your calculated results fall into the “hot,” “dangerously hot,” or “extremely dangerous” zones, or if projected productivity loss reaches 5% or more, it’s time to implement targeted changes. 

We recommend increasing air circulation with industrial HVLS fans, which are a cost-effective way to reduce perceived temperature by up to 10°F without major HVAC overhauls. Additionally, dehumidifiers can help lower moisture levels, while radiant heat from windows or machinery can be mitigated with reflective films or insulation. Small air conditioning adjustments, scheduled during the hottest times of day, can also make a big difference in comfort without driving up energy bills.

How is Heat Index Related to Comfort Level?

Heat index is a widely used reference metric that measures both air temperature and relative humidity to define the apparent temperature, also known as the “feels-like” temperature. As humidity rises, the body’s ability to cool itself through sweat evaporation decreases and disrupts heat balance. This phenomenon leads to a much higher perceived temperature.

Our thermal comfort calculator shows this concept of the heat index by categorizing comfort levels from: “Warm” to “Dangerously Hot," mirroring heat index classifications according to the National Weather Service. 

Source: National Weather Service

These classifications help flag when heat stress and safety risks are elevated, especially in facilities that lack adequate airflow or cooling. Comparing indoor thermal conditions to outdoor temperature trends can also help identify when intervention is most needed, especially in facilities with minimal insulation or high solar heat gain.

What Other Factors Affect Productivity Loss in Facilities?

Individual heat production also varies based on metabolic rate and activity, making it an important consideration in detailed comfort modeling. Many of our warehouse customers report that, in addition to utilizing the thermal comfort calculation, it is important to understand the Predicted Mean Vote (PMV). 

What is Predicted Mean Vote? Predicted Mean Vote (PMV) predicts how occupants evaluate air temperature in a space on a 7-point scale. PMV is calculated using the following factors: 

• Air temperature
• Relative humidity
• Air velocity
• Mean radiant air temperature
• Clothing insulation level (Clo)
• Metabolic rate (Met)

Thermal Comfort Level and Productivity Chart

The chart below provides a thermal comfort visualization. This helps you understand how temperature and humidity interact to influence the thermal environment. These factors affect comfort and performance across different environments. 

Adjust the input values in the calculator window to explore various conditions across simulated or real buildings.

Who Benefits From Our Thermal Comfort Calculator?

LED Lighting Supply’s Thermal Comfort Calculator is designed for professionals responsible for maintaining safe, productive, and energy-efficient indoor environments. This includes:

Facility Managers and Building Operators

1. Monitor indoor temperature and humidity. Adjust as necessary to lower discomfort, maximize comfort, and eliminate employee complaints.
   
   
2. Validate the effectiveness of HVAC systems or supplemental cooling strategies. Consider integrating ceiling fans, wall fans, or drum fans into your facility to work in conjunction with your HVAC system. A Product Specialist at LED Lighting Supply can provide live help to assist in determining the proper solution for your project.
   
   
3. Identify when conditions exceed safe thresholds and consider investing in facility upgrades such as commercial and industrial fans or insulation improvements to meet OSHA standards.

Operations and Safety Managers

1. Quantify heat-related productivity loss and proactively reduce risk of heat stress in high-traffic or labor-intensive environments.
   
   How do you reduce the risk of heat stress in a facility? Some recommendations include ensuring adequate ventilation, providing proper personal protective equipment (PPE), monitoring thermal comfort, and reducing the presence of stagnant air and humidity buildup on equipment.
   
   How to eliminate humidity buildup on equipment? Commercial and industrial ceiling fans help destratify surrounding air while distributing large amounts of warm and cool air throughout the space. This process ensures the temperature is uniform, improves indoor air quality, and keeps conditions comfortable for workers.
   
   
2. Support workplace safety programs with early intervention programs that train facility supervisors to identify dangerously hot conditions before they impact employee health. An example is OSHA’s Protecting Workers from the Effects of Heat pamphlet that outlines heat illness and how to prevent it.
   
   How to protect workers from the risks of heat-related injuries? Building operators and facility managers should closely monitor weather forecasts. This prepares operators to ensure the building maintains optimal environmental conditions.

Industrial Engineers and Workplace Designers

1. Assess thermal comfort in existing spaces or during design planning to ensure compliance with ASHRAE Standard 55.
   
   How to comply with ASHRA Standard 55?

Building design and engineers must consider all employees within a workplace as well as typical indoor and outdoor environmental conditions.

• Seasonal outdoor environmental variations 
• Employees’ seasonal clothing changes
• Short-term average air variability from HVAC system design 
• Indoor variations in air temperature, relative humidity, average air speed, and mean radiant temperature between spaces in the workplace
  • This should include the presence or lack of direct sunlight
    
    

1. Integrate thermal data into workflow optimization, ventilation planning, and equipment layout decisions.

Whether you’re managing a small office or a large industrial plant, this tool gives you the data you need to maintain an improved indoor environment while prioritizing worker comfort, safety, and productivity year-round.

Thermal Comfort’s Impact on Industrial ROI & Productivity 

• Combat Sick Days and Heat Stress: Maintain optimal thermal conditions to prevent heat stress–related slowdowns, unplanned breaks, and equipment operator fatigue that can halt production lines.
  
  
• Avoid Costly Downtime Equipment Strain: Stable and lower indoor temperatures can prevent high operative temperature in sensitive machinery and electrical components, reducing repair costs, lowering energy usage, and extending asset life.
  
  
• Lower Turnover Costs: Proactive comfort management improves employee retention, reducing recruitment and training expenses tied to heat-related dissatisfaction.
  
  
• Maximize ROI from Cooling Investments: Leverage accurate comfort data to target fan and HVAC upgrades where they deliver the greatest productivity gains.

Thermal Comfort’s Impact on Commercial ROI & Productivity 

• Preserve Service Quality: In retail, hospitality, and office environments, comfortable conditions help staff maintain focus, responsiveness, and customer service standards.
  
  
• Increase Operational Consistency: Minimize productivity dips caused by heat-induced fatigue, ensuring daily targets are met without additional labor costs.
  
  
• Increase Customer Retention: Maintain appealing conditions for visitors and clients, which can lead to repeat business and higher satisfaction scores.
  
  
• Improve Space Utilization: Identify and address “hot spots” that make parts of the building underused, ensuring all areas remain functional and profitable.
  
  
• Support Energy Efficiency Goals: Use accurate temperature and humidity data to fine-tune HVAC operations, lowering utility costs while protecting workforce output.