Indoor Climate Standards

A comfortable indoor environment is defined by more than temperature alone. Modern residential, commercial and hospitality buildings require coordinated control of temperature, humidity, ventilation, indoor air quality, airflow distribution and acoustic comfort.

YUJU EnvironTech uses these indoor climate factors as practical design references when developing HVAC and whole-building comfort solutions for different climates and applications.

The values below are intended as general comfort design references. Final project targets should be determined according to local codes, building use, climate conditions, occupancy and project requirements.

1. Indoor Temperature

Stable indoor temperature is one of the most important factors affecting thermal comfort.

Common comfort design reference ranges include:

Actual comfort depends on more than air temperature. Clothing, activity level, radiant temperature, humidity and air movement also influence how occupants experience the indoor environment.

Proper HVAC design should help minimize excessive temperature differences and uncomfortable hot or cold zones.

2. Relative Humidity

Indoor humidity affects thermal comfort, moisture management and overall building conditions.

For many residential and commercial comfort applications, a relative humidity range around:

is commonly used as a practical comfort reference.

However, appropriate humidity targets should be adjusted according to outdoor climate, season, building envelope and application.

Humidity control may require:

• Dehumidification in Hot & Humid Climates
• Humidification in Cold & Dry Climates
• Fresh Air Moisture Management
• Temperature & Humidity Sensors
• Integrated HVAC Control

3. Fresh Air Ventilation

Outdoor air ventilation is essential for maintaining acceptable indoor environmental conditions, particularly in modern airtight buildings.

A properly designed ventilation system helps dilute internally generated contaminants and remove stale indoor air.

Ventilation design should consider:

• Occupancy
• Building Type
• Room Function
• Outdoor Air Quality
• Exhaust Requirements
• Building Pressure Relationships
• Local Ventilation Codes and Standards

CO₂ monitoring can be used as one indicator of ventilation adequacy in occupied spaces, but ventilation design should not rely on CO₂ alone.

4. Indoor Air Quality

Indoor air quality is influenced by outdoor pollutants, occupants, building materials, furnishings, activities and HVAC system operation.

A complete indoor air quality strategy may address:

• Dust
• Pollen
• Pet Dander
• Fine Airborne Particles
• Odors
• Selected VOCs
• Other Indoor Contaminants

Depending on the application, HVAC air treatment may include:

• Pre-Filtration
• MERV-Rated Filters
• High-Efficiency Filtration
• HEPA Filtration for Selected Applications
• Activated Carbon
• Electronic Air Cleaning
• UV-C Air Treatment

Filter selection should also consider airflow resistance, fan capacity and maintenance requirements.

5. Acoustic Comfort

Indoor comfort also depends on sound levels generated by HVAC equipment, air movement and duct systems.

Typical quiet-environment design references may include:

Actual acceptable noise levels depend on building use, background sound and project requirements.

Quiet HVAC design should consider:

• Fan Speed
• Air Velocity
• Duct Dimensions
• External Static Pressure
• Diffuser & Grille Selection
• Equipment Location
• Vibration Isolation

6. Balanced Air Distribution

Even correctly sized HVAC equipment may not provide good comfort if conditioned air is not properly distributed.

A well-designed air distribution system should provide:

• Uniform Room Temperature
• Appropriate Air Velocity
• Balanced Supply & Return Air
• Reduced Drafts
• Reduced Hot and Cold Spots
• Suitable Room Airflow
• Controlled Operating Noise

Airflow calculation, duct sizing, external static pressure and outlet selection should therefore be considered during the HVAC design stage.

Indoor Climate Design by Application

Residential Homes & Villas

Residential projects typically prioritize thermal comfort, quiet operation, fresh air, humidity management and whole-house air quality.

Hotels & Hospitality

Guest comfort requires stable temperature, quiet HVAC operation, suitable ventilation and independent room control.

Office & Commercial Buildings

Commercial projects require a balance between occupant comfort, ventilation, energy efficiency and operational control.

Healthcare & Specialized Facilities

Healthcare, laboratory and controlled environments may require more specific targets for temperature, humidity, ventilation, filtration and room pressure according to application requirements.

Indoor Climate Parameters at a Glance

How YUJU Applies Indoor Climate Standards

YUJU does not use one fixed indoor climate target for every building.

Our engineering approach evaluates:

• Building Type
• Project Location & Climate
• Occupancy
• Heating & Cooling Loads
• Ventilation Requirements
• Humidity Requirements
• Indoor Air Quality Targets
• Airflow & Static Pressure
• Noise Requirements
• Energy Efficiency Objectives

Based on these factors, HVAC equipment, ventilation, humidity control, filtration and intelligent controls can be combined into an appropriate indoor climate solution.