Heat Exhaust Ventilation Systems

Heat from machines, processes and the roof accumulates under the ceiling and gradually warms the whole space. Removing this hot air continuously, and replacing it with outdoor air, lowers indoor temperatures and prevents heat from building up through the day.

High temperatures combined with physical work can cause heat exhaustion, dehydration, cramps and, in severe cases, heat stroke. Industrial heat stress control through good ventilation, air movement and spot cooling keeps workers safer and more alert.

Motors, drives, PLC panels, transformers and DG sets lose efficiency and life when operated in hot rooms. Heat exhaust keeps equipment rooms within their rated operating temperatures and reduces nuisance tripping and breakdowns.

Comfortable workers make fewer mistakes, take fewer breaks and maintain output through the shift. Industrial thermal comfort ventilation also improves morale and helps retain skilled staff.

Air conditioning large, high-roofed factories with high internal heat loads is extremely expensive to install and run. A heat exhaust ventilation system with evaporative make-up air typically costs a fraction of AC to install and uses far less electricity.

Furnaces, heat treatment ovens, kilns and dryers release large amounts of convective and radiant heat. Furnace heat exhaust and industrial oven exhaust often need canopy hoods to capture the rising thermal plume before it spreads into the building.

Injection moulding machines, extruders, presses, hydraulic power packs and CNC machines each add continuous heat through motors, heaters and hydraulic oil. In a plant with dozens of machines, this adds up to a very large heat load.

DG sets reject significant heat through their radiators and engine surfaces, transformers lose energy as heat, and electrical panels and drives generate heat continuously. These rooms need dedicated ventilation to keep equipment within safe limits.

Boilers lose heat through their casings and flue connections, while air compressors convert most of their input power into heat. Boiler room heat exhaust and compressor room ventilation are essential for safe, efficient operation.

Cooking ranges, tandoors, fryers, ovens and dishwashers release heat, steam, smoke and grease. Commercial kitchen exhaust fans and hoods remove this heat and contaminants to keep kitchens workable.

Uninsulated metal roofs in Indian conditions absorb intense solar radiation and radiate heat down into the building. Roof heat gain is often one of the largest heat sources in warehouses and light industrial buildings, and it is best tackled with a combination of roof ventilation and insulation.

Industrial roof exhaust fans and powered roof ventilators are mounted on the roof to remove hot air from the highest point. Roof mounted exhaust fans are available as axial, mixed-flow or centrifugal designs, with weatherproof cowls and backdraft dampers. They are the backbone of most factory heat exhaust systems.

Wall mount exhaust fans and louvered exhaust fans installed high on side walls are a simple, cost-effective way to exhaust hot air, especially in sheds with low roof pitch. Heavy duty industrial exhaust fans in 18-inch, 24-inch and larger sizes are common in workshops, warehouses and shop floors.

Turbine ventilators use wind and thermal buoyancy to spin a vaned head, drawing hot air out of the roof without electricity. They provide low-cost, zero-power ventilation and are widely used on industrial sheds and warehouses.

Continuous ridge vents and raised monitor roofs create permanent openings at the highest point of the building. They allow large volumes of hot air to escape naturally and work well with low-level inlets to drive stack ventilation.

Canopy hoods capture the rising thermal plume from furnaces, ovens and hot tanks before it spreads. A canopy hood heat exhaust system with a high temperature exhaust fan removes concentrated heat and fumes directly at the source.

Weather louvres, sand trap louvres and motorised dampers allow fresh air in while keeping rain and dust out. Correctly sized inlets are just as important as exhaust fans for effective heat removal.

Make-up air units supply filtered fresh air, and evaporative air coolers cool that air before it enters the building. A heat exhaust system with make-up air ensures balanced airflow and better cooling at worker level.

Thermostats, temperature sensors, timers, VFDs and control panels automate fan operation based on indoor temperature, process status or time of day, keeping the system efficient and hands-free.

Powered roof exhaust fans provide reliable, controllable heat removal regardless of wind or weather. They are ideal for factories with high internal heat loads and are easily combined with thermostats and VFDs for automatic control.

High-level wall exhaust fans work well in buildings where roof access is limited or roof penetrations are undesirable. Paired with low-level inlets on the opposite wall, they create cross-ventilation across the working area.

For concentrated heat sources, canopy hood heat extraction captures the thermal plume directly above the equipment. This local heat exhaust, or source capture heat exhaust, removes heat before it mixes with room air and is far more efficient than trying to dilute it.

Natural stack ventilation uses the height difference between low-level inlets and high-level outlets to drive airflow through thermal buoyancy. With correctly sized openings, it can remove substantial heat with no running cost.

Multiple turbine ventilators spaced across the roof provide continuous, zero-energy ventilation. They are popular for warehouses, storage sheds and light industrial buildings with moderate heat loads.

Hybrid systems use natural ventilation or turbine ventilators for everyday operation and powered fans for peak heat conditions. This combination balances energy savings with dependable performance on the hottest days.

Evaporative make-up air units pass outdoor air through wetted pads, cooling it before supplying it to the working area. Combined with roof exhaust, they can deliver cooler air at worker level, especially in dry and moderately humid conditions.

Where cooling the whole building is not practical, spot cooling for industrial heat directs cool or high-velocity air at specific workstations. Man coolers and air circulators are widely used near furnaces, presses and heavy work areas.

High-volume, low-speed (HVLS) ceiling fans move large volumes of air gently across big floor areas. The air movement increases perceived cooling for workers and helps destratify hot air toward roof exhaust points.

DG sets need large volumes of air for combustion and for removing heat rejected by the engine and radiator. We design DG room ventilation with correctly sized inlet louvres, exhaust fans or radiator discharge ducts and acoustic treatment, following the airflow and temperature limits specified by the DG manufacturer.

Transformers lose part of their rated power as heat. Transformer rooms are ventilated with low-level inlets and high-level outlets, supplemented by exhaust fans where natural ventilation cannot keep the room within the transformer's rated ambient temperature.

LT panels, VFDs, UPS systems and control panels generate continuous heat. Electrical room ventilation with filtered supply air and exhaust fans keeps panels cool and dust-free, extending component life and reducing nuisance trips.

Boiler rooms need air for combustion and ventilation to remove radiant and convective heat from boilers, pipework and flues. A boiler room exhaust fan with properly sized fresh air inlets keeps the room safe for operators and ensures clean combustion.

Air compressors convert most of their input energy into heat. Compressor room ventilation ducts hot cooling air directly outside and supplies cool air at the compressor intake, improving compressor efficiency and reliability.

Lift machine rooms house motors, drives and controllers that must operate within the temperature range specified by the lift manufacturer. Wall or roof exhaust fans with thermostatic control maintain safe conditions.

UPS rooms produce heat from inverters, while battery rooms can release hydrogen during charging. Ventilation removes both heat and hydrogen, with exhaust points at high level and spark-resistant fans where required.

For decades, the Factories Act, 1948 required adequate ventilation by the circulation of fresh air, and temperatures that secure reasonable comfort and prevent injury to health, including measures to protect workers from excessive heat. These duties have been carried into the Occupational Safety, Health and Working Conditions Code, 2020, operative since 21 November 2025, with State Factory Rules such as the Maharashtra Factories Rules continuing to guide practical expectations.

The Wet Bulb Globe Temperature (WBGT) index combines air temperature, humidity, radiant heat and air movement into a single measure of heat stress. It is widely used to decide safe work-rest cycles and to assess whether ventilation and cooling measures are effective.

The National Building Code of India 2016, in its building services provisions, sets out requirements and recommended air change rates for natural and mechanical ventilation in different building types and spaces. We use it as a key reference for heat exhaust ACH and ventilation design.

ACGIH publishes heat stress threshold limit values based on WBGT, workload and work-rest patterns, along with action limits for unacclimatised workers. These guidelines help plants set safe working conditions and demonstrate responsible heat exposure control.

We calculate the total heat entering the space from machines, motors, furnaces, ovens, lighting, people and solar gain through the roof and walls. Where possible, we use nameplate ratings, operating hours and site temperature readings. This ventilation heat load calculation is the foundation for every other design decision.

The heat exhaust airflow needed is calculated from the heat load and the allowable temperature rise. As a working rule, airflow in m³/h is roughly 3,000 × heat load in kW ÷ allowable temperature rise in °C. For example, removing 100 kW of heat with a 5 °C rise needs about 60,000 m³/h. We then convert this into heat exhaust CFM, air changes per hour (ACH) and the number and size of fans required.

The allowable temperature rise is the difference between indoor and outdoor temperature that the design accepts. Occupied production areas are typically designed for a small rise of a few degrees, while utility rooms may accept a larger rise within equipment limits. A smaller rise gives cooler conditions but needs more airflow.

Warm indoor air is lighter than cooler outdoor air, creating a natural upward flow known as the stack effect. The taller the building and the greater the temperature difference, the stronger the flow. We design inlet and outlet heights to make the most of this thermal plume exhaust effect.

Inlets are placed low and on the cooler, windward side where possible, and outlets high at the roof or ridge. Inlet free area is generally at least equal to the outlet area, sized for low velocities to limit noise, pressure loss and drafts.

Every cubic metre exhausted must be replaced. Without adequate heat exhaust make-up air, fans cannot deliver their rated airflow, doors become hard to open and hot air may be pulled in from unwanted areas. We plan fresh air heat removal through louvres, openings or evaporative make-up air units.

For exhaust above furnaces, ovens and kilns, we select high temperature exhaust fans and heat resistant exhaust fans rated for the actual air temperature. Designs with motors outside the hot airstream, such as belt-driven centrifugal or bifurcated axial fans, protect the motor and extend its life.

If exhaust outlets are too close to fresh air inlets, hot air is simply drawn back into the building. We separate intakes and discharges, consider prevailing winds and use discharge direction and height to prevent short-circuiting.

For large, complex or critical buildings, computational fluid dynamics (CFD) simulations predict airflow patterns and temperature distribution before installation. CFD helps us test fan locations, inlet sizes and hood designs virtually, avoiding costly changes on site.

Thermostats switch fans on only when indoor temperature rises above a set point, and can stage multiple fans as heat increases. This prevents fans from running unnecessarily during cool mornings, nights and winter months.

A heat exhaust fan VFD varies fan speed to match the actual heat load. EC heat exhaust fans and BLDC exhaust fans use electronically commutated motors that are highly efficient and inherently speed-controllable. Because fan power falls sharply at reduced speed, even modest speed reductions produce large energy savings.

Turbine ventilators, ridge vents and natural stack ventilation remove heat without any electricity. Where the heat load and building allow, they form the base of a low-energy system, with powered fans added only for peak conditions. Solar powered ventilation fans are another option for remote or off-grid areas.

Evaporative air coolers use a fraction of the power of refrigerated air conditioning to deliver cooler supply air. In many Indian climates, evaporative make-up air combined with roof exhaust provides comfortable working conditions at a much lower cost.

Reducing heat entering through the roof lowers the heat load the ventilation system has to remove. Under-deck insulation, insulated roofing and reflective cool roof coatings can significantly reduce roof heat gain, allowing smaller fans and lower running costs.

Hot air from compressors and some process exhausts can be recovered for useful purposes, such as drying, space heating or preheating process air, instead of being wasted. Where there is a suitable heat demand, recovery improves overall plant efficiency.

Temperature sensors placed at working level and near the roof give an accurate picture of heat conditions. They drive fan staging, speed control and alarms for high temperatures.

VFDs provide smooth, stepless fan speed control linked to temperature, reducing energy use and noise while extending motor and belt life through soft starting.

DG room ventilation fans can be interlocked with the DG set so they start automatically when the engine runs, and continue for a set time after shutdown to remove residual heat.

In the event of a fire, heat exhaust fans may need to stop to avoid feeding the fire or switch to a smoke exhaust mode, depending on the building's fire strategy. We interface fan controls with the fire alarm panel to follow the approved fire safety plan.

Heat exhaust BMS integration brings fan status, temperatures, alarms and energy data onto your building management system for central monitoring and scheduling, enabling demand controlled heat exhaust across the facility.

Continuous removal of hot air brings indoor temperatures much closer to outdoor levels and prevents heat from building up through the day.

Cooler, fresher air reduces fatigue, dehydration and heat-related illness. Workers stay more alert and productive, and absenteeism falls during the hottest months.

Motors, drives, panels, transformers and DG sets run cooler, more efficiently and with fewer failures when their surroundings are properly ventilated.

Heat exhaust ventilation costs a fraction of air conditioning to install and run in large industrial spaces, making it the practical choice for factories and warehouses.

The same airflow that carries away heat also removes smoke, fumes, odours and airborne moisture, improving overall indoor air quality.

Turbine ventilators, ridge vents and natural stack ventilation remove heat with zero running cost, and thermostatic and VFD controls minimise fan energy when mechanical exhaust is needed.

Ventilation alone can only bring indoor temperature close to outdoor levels. Where lower temperatures are required, evaporative cooling, spot cooling or air conditioning for specific areas is added.

Large inlets and outlets can admit dust and monsoon rain. Weather louvres, sand trap louvres, filters, cowls and backdraft dampers keep ingress under control.

Large exhaust fans can be noisy, particularly at full speed. Correct fan selection, lower-speed operation with VFDs, anti-vibration mounts and silencers keep noise within acceptable limits.

Evaporative cooling adds moisture to the air, which reduces its effectiveness in very humid weather and may not suit humidity-sensitive processes. Adequate exhaust rates and correct sizing keep humidity manageable.

Effective heat removal needs substantial openings for air to enter and leave. In existing buildings, creating these openings may require structural and roofing work, which we plan carefully with you.

An industrial heat exhaust system for a factory removes heat from machines, processes and the roof, keeping shop floors workable through the summer. Industrial roof exhaust fans, wall fans and evaporative make-up air are the most common combination.

Foundry heat exhaust handles intense radiant and convective heat from melting furnaces, pouring and forging. Monitor roofs, canopy hoods, high temperature exhaust fans and man coolers work together to protect workers.

Metal processing heat exhaust in rolling mills, reheating furnaces and glass furnaces requires very high airflows and heat-resistant equipment. Natural stack ventilation through large roof monitors is often combined with powered exhaust.

Injection moulding machines, extruders and chillers generate continuous heat. Roof exhaust and evaporative make-up air keep production halls cooler and help stabilise product quality.

Textile processing and spinning areas generate heat from machines and lighting and often need controlled humidity. Heat exhaust is designed alongside humidification and air washer systems.

Warehouse exhaust fans, turbine ventilators and HVLS fans reduce roof heat build-up, protect stored goods and improve comfort for staff in large, high-roofed buildings.

Commercial kitchen exhaust fans and hoods remove heat, smoke, steam and grease from cooking areas, with fresh air supply to balance the exhaust and keep kitchens comfortable.

Dedicated ventilation keeps DG sets, transformers and electrical panels within their rated operating temperatures, protecting critical power infrastructure.

Boiler and compressor rooms need combustion air, cooling air and heat exhaust to operate safely and efficiently. We design ducted discharge and fresh air supply for these high-heat rooms.

Ovens, fryers, steam cookers and packaging lines release heat and moisture. Heat exhaust with hygienic design and appropriate filtration keeps food processing areas comfortable and compliant.

Printing presses, dryers, ironers and industrial washers produce heat, humidity and sometimes solvent vapours. Heat exhaust ventilation removes these, improving comfort and protecting equipment.

Kruger is a Singapore-headquartered fan manufacturer with a strong presence in India. It is known for centrifugal, inline and axial fans widely used in HVAC and industrial ventilation projects.

Systemair is a Swedish ventilation company offering a broad range of fans, air handling units and air distribution products. Its axial, roof and inline fans are used in commercial and industrial buildings.

Nicotra Gebhardt is a fan brand with Italian and German roots, known for centrifugal fans, plug fans and fan modules for air handling and industrial applications.

Greenheck is a US-based manufacturer of air movement and control equipment. Its roof exhaust fans, industrial fans, louvres and dampers are used in commercial and industrial ventilation worldwide.

Almonard is an Indian manufacturer of industrial fans, including exhaust fans, air circulators and ventilation fans for factories and commercial spaces.

Several leading Indian electrical brands offer heavy duty industrial exhaust fans, while specialist manufacturers supply turbine ventilators, HVLS fans, evaporative air coolers and louvres. Our team helps you compare these options for quality, performance and value.

*Brand names are trademarks of their respective owners and are mentioned for reference only.*

We record temperatures at working level and near the roof at multiple points before installation and again after commissioning under similar conditions. This shows the real reduction in indoor temperature and the difference between indoor and outdoor conditions.

Airflow is measured at fans, louvres and hoods using anemometers and flow hoods, and compared with design values. Fan speed and damper settings are adjusted to achieve the designed air changes.

Thermal imaging cameras reveal hot spots on roofs, walls, equipment and ceilings, helping confirm that heat is being removed where it matters most and identifying any areas that need fine-tuning.

Thermostats, VFDs, timers, DG interlocks, fire alarm interfaces and BMS signals are tested to confirm the system responds correctly in every operating mode.

You receive a performance report covering temperature readings, airflow measurements, thermal images, control settings and recommendations, along with operation and maintenance manuals.

Dust, oil mist and debris on fan blades and motors reduce airflow and cause overheating. Regular cleaning restores performance and extends motor life.

Bearings are checked for noise, temperature and lubrication, and belts for wear and tension. Timely replacement prevents unexpected breakdowns during peak summer.

Turbine ventilators are inspected for smooth rotation, bearing wear, vane damage and secure fixing, and serviced to keep them spinning freely.

Intake louvres, bird screens and backdraft dampers are cleaned and checked so fresh air can enter freely and dampers open and close properly.

Cooling pads are cleaned or replaced, water tanks flushed, pumps and distribution checked and bleed-off adjusted to prevent scaling, odour and bacterial growth.

Thermostats and temperature sensors are verified and recalibrated, and control sequences reviewed so fans start, stage and stop at the right temperatures.

Cause: Concentrated heat sources with no local capture, or fans placed far from the heat. Solution: Add canopy hoods or local heat exhaust above hot equipment, relocate or add fans, and provide spot cooling at affected workstations.

Cause: Undersized or too few fans, worn belts, dirty blades, or inadequate inlet openings starving the fans. Solution: Recalculate the heat load and airflow, service or upgrade fans and enlarge or add inlet louvres.

Cause: Exhaust discharges close to fresh air inlets, or inlets placed high where hot air collects. Solution: Relocate inlets to low level and away from discharges, redirect fan outlets and use prevailing wind to advantage.

Cause: Open inlets without louvres, damaged cowls or poorly sealed roof penetrations. Solution: Fit weather or sand trap louvres, filters, rain cowls and backdraft dampers, and re-seal roof curbs and flashings.

Cause: Motors in hot airstreams, dust build-up, overloading or poor maintenance. Solution: Use high temperature rated fans with motors outside the airstream, clean regularly, correct fan duty and add VFD soft starting.

Cause: Fans running at high speed, unbalanced impellers, loose mountings or undersized openings creating high air velocity. Solution: Add VFDs, balance impellers, fit anti-vibration mounts and silencers, and enlarge openings.

Cause: Too little exhaust relative to evaporative supply, or operation during very humid weather. Solution: Increase exhaust airflow, add humidity-based controls and switch to ventilation-only mode when outdoor humidity is high.

Adding powered roof extractors or turbine ventilators to an existing roof is often the fastest way to reduce heat build-up. We handle roof cutting, curbs, installation and weatherproofing.

Retrofitting evaporative air coolers or make-up air units supplies cooler fresh air to working areas and improves the performance of existing exhaust fans.

Upgrading manual fans to thermostatic and VFD control reduces energy use and keeps conditions consistent without operator intervention.

HVLS fans improve air movement and perceived cooling over large floor areas, and help push hot air toward roof exhaust points.

Adding under-deck insulation, insulated roofing or cool roof coatings reduces roof heat gain at the source, making the entire ventilation system more effective.

Total airflow, set by the heat load and allowable temperature rise, determines the number and size of fans. Axial heat exhaust fans are the most economical per unit of airflow, while centrifugal heat exhaust fans and high temperature rated fans cost more but handle ducted systems, higher static pressure and hot air.

Turbine ventilators cost far less per unit and have no running cost, but each moves much less air, so many units are needed. Powered roof exhaust fans cost more per unit and use electricity, but deliver high, guaranteed airflow from fewer roof openings. The best value often comes from combining both.

Evaporative make-up air adds equipment, ductwork, water supply and drainage costs, but delivers noticeably cooler air at worker level. It is typically far cheaper to install and run than refrigerated air conditioning for the same floor area.

• Total heat load and required airflow
• Fan type, size, drive and temperature rating
• Mix of powered fans, turbine ventilators and natural openings
• Roof type, height, access and structural work for openings
• Canopy hoods and heat exhaust ductwork for hot processes
• Evaporative cooling, make-up air and supply ducting
• Louvres, dampers, weatherproofing and bird protection
• Controls: thermostats, VFDs, DG interlocks and BMS integration
• CFD analysis for complex buildings
• AMC and maintenance over the system's life

A correctly designed system avoids both underperformance on the hottest days and the cost of oversized equipment, giving you the best long-term value.