thermal load analysis for hot yoga studio

Case Study: Thermal Load Analysis for Hot Yoga Studio in New Jersey

houseNextBLDG Feb 18, 2026

Introduction: Engineering a 95°F Environment for a Hot Exercise Studio

Designing a hot yoga or heated fitness studio requires a thermal analysis that goes well beyond conventional HVAC sizing. Maintaining a consistent 95°F interior environment with controlled humidity introduces significant heating, insulation, and ventilation demands that typical commercial systems are not designed to handle.

For a proposed gym and dance studio in Clark, New Jersey, NextBLDG Architecture & Engineering, P.C. performed a comprehensive heat load evaluation to determine:

  • Required heating capacity
  • Insulation upgrades
  • Ventilation penalties
  • Infrared heater performance
  • Code compliance considerations

At NextBLDG, we integrate architectural design, mechanical engineering, and building envelope analysis to support specialty environments that function as intended. This case study outlines how we evaluated thermal performance and identified the upgrades necessary to reliably sustain hot yoga conditions.

Code Framework and Engineering Basis

New Jersey does not prescribe a specific Btu per hour requirement for hot yoga studios. Mechanical systems must be sized using accepted engineering methods aligned with occupancy, envelope conditions, and ventilation demand.

The analysis referenced the 2021 New Jersey Building Code provisions governing insulation performance, flame spread ratings, heating equipment installation, and thermal separation of conditioned spaces. Heating capacity was evaluated using ASHRAE-based load calculations, manufacturer performance data, and envelope heat transfer modeling.

The code establishes safety requirements. Engineering determines whether the space will perform at 95°F under winter design conditions.

Design Conditions for the Hot Yoga Studio

Indoor Design Conditions

  • Target temperature: 95°F
  • Relative humidity: below 60 percent
  • Typical occupancy: 1 person per 35 square feet
  • Maximum design density: 1 person per 21 square feet

Existing Building Conditions

  • Existing furnace output approximately 45,000 Btu per hour

  • Designed for 70°F operation

  • Studio volume: 9,480 cubic feet

  • 10-foot drop ceiling with 6-foot unconditioned plenum

  • Envelope performance:

    • Drywall approximately R-0.5

    • Masonry wall approximately R-2

    • Concrete slab approximately R-1

    • Single-pane glazing approximately R-1

The building was not designed to maintain elevated temperature conditions.

Infrared Heater System Evaluation

The selected system consisted of twelve SSHC Model 28RCL-2 infrared heaters.

Heater Output

  • 1,200 watts per unit
  • 14,400 watts total
  • Approximately 49,100 Btu per hour

Infrared heating delivers radiant energy directly to occupants and floor surfaces rather than relying entirely on air temperature. This makes it suitable for hot yoga environments where perceived warmth and uniform heat distribution are critical.

However, heater output must exceed conductive and ventilation losses to maintain stable temperature conditions.

Heat Loss Modeling Scenarios

Three envelope conditions were evaluated.

Configuration 1: Sheetrock Stops at 10 Feet

  • Building heat load approximately 89,000 Btu per hour
  • Net result: heating deficit

Configuration 2: Sheetrock Extends to Ceiling Without Insulation Upgrade

  • Building heat load approximately 40,000 Btu per hour
  • Studio heat loss exceeding 49,000 Btu per hour
  • Net result: heating deficit

Configuration 3: Full Insulation Upgrade

  • R-13 wall insulation
  • R-38 ceiling insulation
  • Studio heat loss approximately 22,000 Btu per hour
  • Net result: thermal surplus

Only the fully insulated configuration provided sufficient thermal resistance for the infrared system to maintain 95°F reliably.

Detailed Heat Loss Breakdown

Under upgraded insulation conditions:

  • Ceiling at R-38: approximately 625 Btu per hour
  • Glass wall and door: approximately 5,750 Btu per hour
  • Concrete slab: approximately 11,850 Btu per hour
  • Exterior wall at R-13: approximately 1,720 Btu per hour

The slab and glazing represent the dominant heat transfer paths.

Additional Thermal Load Contributors

Occupant Heat Gain

Each participant generates approximately:

  • 1,200 Btu per hour sensible heat
  • 350 Btu per hour latent heat

For 28 occupants:

  • 34,000 Btu per hour sensible
  • 10,000 Btu per hour latent
  • 44,000 Btu per hour total

Occupant heat materially affects both temperature and humidity levels.

Ventilation Heating Load

At 20 CFM per person:

  • Outdoor air volume approximately 560 CFM
  • Winter heating penalty approximately 52,000 Btu per hour

With a properly sized heat recovery ventilator:

  • Reduced to approximately 12,000 Btu per hour

Ventilation strategy is central to energy performance.

Why Hot Yoga Studios Fail Thermally Without Engineering Analysis

Many hot yoga studios struggle to reach or maintain target temperatures because the space was never engineered for 95°F operation.

Undersized Heating Equipment

Standard commercial HVAC systems are typically sized for comfort heating between 68°F and 75°F. Attempting to raise that same space to 95°F creates a temperature differential that exceeds original design assumptions.

Without proper load calculations, systems short-cycle or run continuously without achieving setpoint.

Ignoring Envelope Heat Loss

Tenant fit-outs often occur in buildings with:

  • Minimal wall insulation
  • Uninsulated plenum spaces
  • Poor-performing glazing
  • Thermal bridging at structural elements

If conductive heat loss is not modeled, radiant systems cannot overcome envelope deficiencies.

Ventilation Overload

Outdoor air requirements dramatically increase heating demand during winter months. In many conversions, ventilation is added without evaluating its energy impact.

The result is a heating system fighting against continuous cold air introduction.

Engineering analysis prevents these predictable failures.

Radiant Heat vs. Forced Air in Hot Yoga Design

Heating method selection significantly affects performance and comfort.

Why Radiant Heat Performs Better at 95°F

Radiant systems:

  • Transfer energy directly to occupants and floor surfaces
  • Reduce air stratification
  • Avoid high-velocity drafts
  • Provide stable perceived warmth

Because radiant energy heats surfaces rather than just air, comfort can be achieved without excessive air movement.

Limitations of Conventional Furnaces

Forced-air systems in hot yoga applications:

  • Create uncomfortable drafts
  • Struggle with humidity control
  • Experience high cycling frequency
  • Lose efficiency at large temperature differentials

Radiant heating is often more suitable for sustained elevated temperature conditions when paired with adequate insulation.

Humidity Control and Mold Risk in Heated Studios

Humidity management is as important as temperature control.

Latent Load from Occupants

At 28 occupants generating approximately 10,000 Btu per hour of latent heat, moisture accumulation becomes significant. Without controlled ventilation and dehumidification, condensation risk increases.

Vapor Drive and Condensation Risk

At 95°F interior temperatures during winter, vapor pressure differentials can drive moisture into wall assemblies. If insulation and vapor control layers are not continuous, condensation may occur within cavities.

Over time, this can lead to mold growth, material degradation, and indoor air quality concerns.

Role of Heat Recovery Ventilators

An HRV allows fresh air exchange while recovering thermal energy from exhaust air. This reduces heating penalties and stabilizes humidity levels.

Proper integration of heating and ventilation is essential in specialty heated environments.

Code-Related Thermal Considerations

New Jersey code does not mandate a specific heating output for specialty uses. Systems must safely support intended occupancy conditions.

Insulation materials must comply with flame spread and smoke development requirements. Added insulation does not materially impact structural load capacity in this application.

Thermal separation between conditioned studio space and unconditioned plenum space is critical to system performance.

Engineering Conclusions

The analysis demonstrated:

  • Infrared heaters provide approximately 49,100 Btu per hour
  • Full insulation upgrades are required
  • Ventilation loads significantly affect system sizing
  • HRV integration substantially reduces heating penalties
  • The existing furnace cannot support 95°F operation

With coordinated envelope upgrades and mechanical design, the studio can reliably sustain required hot yoga conditions.

Work With a Team That Engineers Performance

Designing a hot yoga studio requires coordinated architectural detailing, mechanical load modeling, and ventilation strategy. Heating equipment selection alone is insufficient.

NextBLDG Architecture & Engineering, P.C. provides integrated architectural and engineering services that evaluate building envelope performance, radiant heating design, ventilation penalties, and code compliance in a single coordinated approach.

If you are developing a heated fitness space or specialty occupancy, our team can deliver the detailed thermal analysis required to ensure your space performs reliably and efficiently from day one.