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Considerations for Selecting the Appropriate Climate Control Equipment
Whether you're facing a system breakdown, managing a construction project, or planning a special event, the cost of inadequate temperature control extends far beyond comfort — it impacts your bottom line in ways you might not realize. But how do you ensure adequate cooling while optimizing costs and efficiency? Temporary HVAC job sizing. In this article, we’ll walk you through the essential considerations, heat load calculations, and application-specific guidance for selecting and properly sizing cooling solutions. Click any of the links below to learn more:
Key Takeaways
- Excessive heat often costs more than the investment in temporary HVAC rentals.
- Understanding heat load calculations can reduce equipment costs while ensuring adequate cooling.
- Different environments require specific cooling approaches based on unique variables.
- Early collaboration with climate control experts leads to optimal, cost-effective solutions.
How to Size a Temporary HVAC Rental
The path to effective temporary climate control starts with understanding your actual cooling requirements. At times, facilities and project managers may find themselves with inadequate climate control. If they overestimate their needs, it can lead to unnecessary costs. If they underestimate them, it can cause inadequate performance and cooling.
Achieving optimal results begins with a systematic approach to calculating the cooling load. This process starts with understanding the basic space requirements and then adjusting for specific factors that influence cooling demand.
The Hidden Costs of Heat
Before diving into actual calculations, let's understand what's at stake. The costs of excessive heat extend far beyond discomfort and manifest in four key areas:
- Products and Services: Heat-related mistakes result in more defects and lower quality output.
- Employee Impact: Increased turnover and absenteeism when working conditions become uncomfortable.
- Productivity: Decreased worker and economic output due to environmental stress.
- Safety Concerns: Heat-related illness risks due to environmental conditions.
Excessive heat often costs more than the investment in temporary cooling. The key is determining the right solution for your specific situation.
Basic Sizing Guidelines
Start with requirements in an empty room and our approximate square footage guidelines for comfort cooling (maintaining spaces between 75-85°F).
These baseline figures assume:
- Well-sealed building with proper insulation
- No minimum air changes per hour required
- No significant internal heat sources
- Conditioned space of 12 feet or less in height
However, real-world situations rarely align with these ideal conditions, necessitating adjustments to the baseline calculations due to several key factors.
Contributing Factors
Calculations for temporary HVAC job sizing will need to be adjusted based on the specific conditions of your situation.
Areal Extent: The total square footage requiring climate control forms your baseline calculation.
Openings: Doorways, windows, and other access points allow heat exchange between conditioned and unconditioned spaces. Each opening can increase requirements depending on usage patterns.
Insulation Quality: Resistance to heat transfer depends on the R-value of your building materials. For example, a metal roof deck with no insulation (R-value 3.3) transfers heat much more readily than 6" fiberglass insulation (R-value 19).
Ceiling Height: Spaces taller than 12 feet will require additional cooling capacity.
Solar Loading: Direct sunlight through windows or on roof surfaces can increase temperatures by 20-40°F, creating surface temperatures as high as 130°F. South and west-facing glass typically requires the most adjustment because it receives more light throughout the day.
Internal Heat Sources: Equipment, lighting, and people all generate heat. For reference, each person adds approximately 250 BTUs per hour, while computers, machinery, and appliances can contribute significantly more.
Temperature and Humidity Requirements: Special applications like server rooms, healthcare facilities, or manufacturing processes may require tighter temperature control or specific humidity ranges.
Once you’ve determined the factors that contribute to heat, there are simple calculations that can help you approximate the heat load for your situation.
Heat Gain Through the Roof
One of the most significant factors in cooling calculations is heat transfer through the roof, especially in buildings with large roof areas relative to their overall size. To calculate this accurately, you need to understand the insulation values (R-values) of your roof materials.
When multiple types of insulation are used, separate heat gain calculations must be performed for each material and area. Then, these results should be summed to determine the total heat gain for the space. Here’s how to calculate heat gain through a roof:
- Determining the R-value of your roof material (insulation value)
- Calculate the U-value (thermal transmittance): U = 1/R
- Identify the temperature difference (ΔT) between outside and inside
- Determine the roof area (A)
- Calculate the heat load (Q) using the formula: Q = U × A × ΔT
Example Calculation:
R = 13 SF·°F/BTU
U= 0.077 BTU/SF ·°F
ΔT = 100ºF (outside) - 80ºF (inside) = 20ºF
A = 14,400 SF
Q = 0.077 BTU/SF·°F x 14,400SF x 20ºF
Q = 22,176 BTUs
This 22,176 BTUs represents the cooling capacity needed just to counter heat gain through the 3.5” fiberglass insulated roof. You'll need to add this to other heat sources to determine your total cooling requirement.
These versatile solutions cool indoor air by removing heat and exhausting it outside through flexible ducting. Their main advantages include easy installation, mobility, and no requirement for external water connections. They are ideal for use in office environments, retail spaces, schools, and temporary structures where quick and reliable cooling is needed.
Some models also provide heating and dehumidifying capabilities, allowing for year-round climate control with a single unit. It's important to carefully consider their placement to ensure that the hot air exhaust does not recirculate into the cooled space.
These solutions utilize water as a heat transfer medium, making them exceptionally efficient in environments where water is readily available. They operate by circulating water through the condenser to absorb heat, then sending the warmed water to an external cooling source like a cooling tower or chiller.
Water-cooled units excel in locations where air exhaust options are limited or where exceptionally quiet operation is required. Hospitals, data centers, hotels, and manufacturing facilities often favor these systems for their energy efficiency and consistent performance. These units typically produce less noise than air-cooled alternatives but require proper water connections and various drainage considerations.
Also known as "swamp coolers," these units utilize the natural cooling effect of water evaporation. They draw warm air through water-saturated pads, causing the water to evaporate and reducing the air temperature before circulating it into the space. Unlike traditional air conditioning, they don't use refrigerants or compressors, making them energy-efficient alternatives in appropriate environments.
These units work best in drier climates like warehouses, manufacturing facilities, loading docks, outdoor events, and other large, semi-open spaces. Evaporative coolers can reduce temperatures by 15-20°F in ideal conditions while using up to less electricity than refrigerant-based systems. However, they do increase humidity levels and require regular water supply, making them less suitable for environments where moisture control is critical.
Application-Specific Approaches
Different environments require tailored cooling strategies.
Comfort Cooling
Focuses on occupant comfort in offices, schools, and retail spaces. ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) guidelines suggest that a comfortable temperature range for humans is between 67°F and 82°F.
Construction
Maintains optimal conditions for application and curing of interior finishes and coatings, often requiring precise humidity control alongside temperature management.
Process Cooling
Meets the specific demands of manufacturing equipment, pharmaceutical processes, or product storage with exact temperature and humidity parameters.
Heat Remediation
Provides targeted cooling for personnel working in extreme conditions, such as industrial plants or emergency response scenarios.
Spot Cooling
Addresses specific areas within larger spaces, focusing cooling power where it's most needed rather than conditioning entire facilities.
Selecting the right involves understanding your current needs and anticipating their evolution throughout your project or operational timeline. At Sunbelt Rentals, we've found that the most successful deployments begin with a comprehensive site assessment that considers both environmental factors and operational requirements. Our Climate Control specialists can design custom solutions that combine different equipment types and approaches to achieve optimal results while minimizing costs.
Alternative Cooling Options
Server Room Cooling
Data centers and server rooms present unique challenges due to their constant, concentrated heat output. Here's a simplified approach to sizing:
- Use the kW rating of the uninterruptible power supply (UPS) to determine electronic heat loads.
- Multiply kW by 3,413 BTUs/kW to find total heat generation.
- Divide by 12,000 BTUs/ton to calculate required tonnage.
- Add capacity for the room size (approximately 1 ton per 400 SF)
Example: A 24 kW UPS in a 400 SF server room requires approximately 8 tons of cooling capacity.
Additional considerations include required temperature differential, equipment placement, and airflow management to prevent hot spots.
Tent and Outdoor Event Cooling
Large temporary structures and smaller outdoor event tenting require specialized approaches:
- Tents with sides typically require approximately 1 ton of cooling per 125 SF.
- Plan for 1 ton of cooling per 24 people (more if they’re active).
- Clear tents or those on asphalt surfaces need additional capacity.
- For open tents in hot weather, evaporative coolers may be more effective than traditional air conditioning.
For a 600 SF tent with 60 people, plan for approximately 7 tons of cooling capacity.
Process and Industrial Cooling
Manufacturing and industrial applications often combine comfort cooling with process-specific requirements:
- Start with basic comfort cooling calculations for the space.
- Add specific BTU requirements from process equipment, ovens, and furnaces.
- Consider minimum air changes needed for air quality.
- Evaluate whether spot cooling specific areas would be more efficient than whole-facility approaches.
Large industrial spaces may benefit from a zoned approach, treating critical areas as separate cooling challenges.
Discover the Right Climate Control Solution for You
Selecting the right temporary HVAC solution requires understanding both the technical specifications and the practical applications. While heat load calculations may seem straightforward, accurately determining variables and adjusting for real-world conditions requires expertise. That's where our team's years of field experience becomes invaluable. We've encountered virtually every climate control challenge and developed efficient, cost-effective solutions to help solve them.
Sunbelt Rentals partners with you to create optimal, cost-effective cooling solutions for any application. We provide free assessments to right-size your temporary climate control needs, avoiding both inadequate cooling and unnecessary equipment costs. Our nationwide network ensures equipment availability whenever and wherever you need it, along with 24/7 service support to maintain optimal performance throughout your rental period.