In Vietnam's tropical climate, heat stress isn't a seasonal inconvenience — it's a year-round productivity crisis. Hamilton Air HVLS fans deliver the large-volume, low-speed airflow that poultry houses, pig barns, cattle sheds, and aquaculture facilities need to protect animal welfare, reduce mortality, and recover lost output.
Effective temperature reduction in the animal zone via convective cooling
8°CReduction in mortality risk during peak heat season for poultry flocks
40%Energy savings versus conventional exhaust and ceiling fan systems
70%Floor coverage from a single Ø7.3m HVLS fan at full diameter
1,800m²The Problem
Between April and October, temperatures in Vietnam's key agricultural provinces — Đồng Nai, Bình Dương, Long An, Hà Nam, Thái Bình — routinely exceed 36–40°C with relative humidity above 80%. For livestock, this isn't discomfort. It's a biological crisis.
Heat stress suppresses feed intake, reduces growth rates, drops egg production, impairs reproduction, and — at peak severity — causes mass mortality events. Pigs begin showing stress at 27°C. Broiler chickens at 30°C. Dairy cows at 25°C. Every degree above those thresholds compounds the loss.
Traditional responses — exhaust fans, wall-mounted axial fans, evaporative cooling pads — manage symptoms but don't solve the underlying problem: stagnant air at the animal level. HVLS fans address the root cause by generating continuous, large-volume airflow that reaches where animals live, sleep, and feed.
Heat stress cost drivers
Poultry: Egg production drops 15–30% above 32°C. FCR deteriorates. Broiler weights fall 200–350g below target at slaughter.
Pigs: Sow conception rates drop below 60% during summer. Grow-finish ADG decreases 18–25%. Feed-to-meat conversion worsens significantly.
Dairy cattle: Milk yield falls 10–25%. Somatic cell counts rise. Reproductive performance collapses above 28°C THI.
Ammonia build-up: Stagnant, humid air accelerates ammonia generation from litter and manure — a respiratory hazard for both animals and farm workers.
Disease pressure: Poor air quality and thermal stress suppress immune function, increasing vulnerability to respiratory diseases and bacterial infections.
The Science of HVLS Cooling
An HVLS fan doesn't cool air — it moves it. And that movement, precisely delivered to the animal zone, triggers three distinct biological and physical mechanisms that together drive down effective temperature and ammonia exposure.
"A single Ø7.3m HVLS fan, when properly positioned, can move the same volume of air as 20–34 conventional ceiling fans — at a fraction of the energy cost and noise level."
Hamilton Air Engineering Team — Farm Ventilation Design Guide 2026
4–8°C
Convective cooling effect. Air moving at 1.5–2.5 m/s over an animal's skin increases convective heat loss — the wind-chill effect — reducing perceived temperature by 4–8°C without any refrigeration.
30–50%
Ammonia reduction. Continuous air circulation dilutes ammonia concentrations near the floor and accelerates litter drying — cutting ammonia generation at the source by 30–50% in controlled barn studies.
Ø7.3m
Destratification column. Large-diameter blades push a wide, gentle airflow column from ridge to floor — eliminating the hot, humid dead zone at ceiling level and delivering cooler air directly to animals.
The HVLS Science: Step by Step
Understanding the airflow chain helps farm managers set fan speed correctly, position fans optimally, and integrate HVLS with existing tunnel systems for maximum cooling performance.
Blade rotation
Aluminium alloy blades (Ø3m–7.3m) rotate at 20–60 RPM — far slower than conventional fans. Their large surface area compensates through volume: a single revolution moves an enormous cross-section of air downward. This low-velocity movement is critical — high-speed fans create turbulence and noise that stress birds and disturb feeding behaviour. HVLS flow is smooth, broad, and silent.
Destratification
In any enclosed barn, thermal stratification creates a hot ceiling layer 4–8°C warmer than floor level. This wasted heat radiates back down onto animals. The downward air column from an HVLS fan disrupts stratification entirely — mixing ceiling and floor air into a uniform temperature zone. Animals benefit from the cooler, blended air rather than sleeping under a radiant heat layer.
Convective cooling
When air moves across an animal's body at 1.5–2.5 m/s, convective heat transfer from skin to air accelerates. For a pig or cow, this produces a perceived temperature reduction of 4–8°C — without any mechanical refrigeration. The animal's body temperature decreases, respiratory rate drops, feed intake resumes, and productive behaviour returns. This is the core mechanism that makes HVLS fans dramatically more effective than stagnant room air alone.
Litter & floor drying
Ammonia generation in poultry litter and pig slurry is an enzymatic process that accelerates dramatically in wet, warm, stagnant conditions. HVLS airflow accelerates surface evaporation from litter and flooring, keeping moisture content below the threshold where ammonia generation peaks. Farms consistently report 30–50% lower ammonia readings after HVLS installation — protecting animal lung health and meeting occupational safety thresholds for farm workers.
Integration with tunnel systems
Tunnel ventilation moves air longitudinally — but loses velocity near sidewalls and in mid-house zones beyond 60m from the inlet. HVLS fans positioned overhead fill these dead zones with transverse airflow, ensuring every animal in the building receives adequate air movement regardless of their position relative to the tunnel. The two systems are fully complementary and together create a barn microclimate that no single technology achieves alone.
Hamilton Air HVLS Fan Line
Hamilton Air branded HVLS line – gearless PMSM motor, aerodynamic aluminium blades, IP55 to IP68 protection. Coverage from 600 m² to 2,000 m² per fan.
Standard range – ideal for light manufacturing workshops, showrooms, supermarkets, sports halls. Gearless PMSM motor, VFD control, minimum ceiling height 3.5m.
View Details →Compact version – optimised for mid-size warehouses, workshops, schools. Minimum ceiling height 3.0m, lightweight, easy installation.
View Details →Latest generation – 3-phase 380V PMSM motor, IP65 dust and pressure water protection. Optional IoT connectivity, app control. Ideal for logistics warehouses and manufacturing plants.
View Details →ADF (Advanced Distributed Fan) technology – uniform airflow distribution, hot spot reduction. Optimised for shopping centres and mixed-use workshops.
View Details →IP65/IP68 rated – unique on the Vietnam market. Stable operation under direct washdown: food factories, aquaculture, seafood processing.
View Details →Flagship – 8-blade ADF up to 7.3m diameter. Maximum airflow for mega logistics warehouses, airports, exhibition centres and large sports arenas.
View Details →Energy & ROI
For a representative 2,000 m² broiler house running 20 hours/day, 300 days/year in Đồng Nai province, the energy economics of HVLS versus conventional fan systems are unambiguous.
Conventional fans
504M
VND / 5-year electricity cost
24 wall fans × 700W × 6,000h/yr × 2.5 VND/kWh × 5yr
Hamilton Air HVLS
135M
VND / 5-year electricity cost
3 HVLS Ø7.3m × 900W × 6,000h/yr × 2.5 VND/kWh × 5yr
5-year electricity saving
369M
VND — before productivity gains
Additional: reduced mortality, improved FCR & egg production not included
HVLS fans improve ventilation, animal health, and crop productivity in agricultural facilities:
Hamilton Air specializes in providing HVLS (High-Volume, Low-Speed) ceiling fans for a wide range of commercial, industrial, educational, and public spaces. Designed for large areas with high ceilings, HVLS fans improve air circulation, reduce temperature hotspots, and create comfortable environments for both workers and visitors. Below is a comprehensive list of spaces where HVLS fans can make a significant difference.
Overhead fans are widely used in industrial, commercial, and residential spaces to improve air circulation, reduce energy costs, enhance comfort, and maintain a healthier indoor environment.
Heavy-duty HVLS fans for factories, warehouses, and large-scale facilities.
Efficient cooling solutions for gyms, malls, offices, and public spaces.
Elegant ceiling fans designed for homes, villas, and outdoor living areas.
Industrial HVLS fans with powerful airflow and superior dust/water resistance.
Reliable energy-saving fans for semi-outdoor and industrial applications.
Commercial-grade HVLS fans delivering strong airflow and cost efficiency.
Stylish residential ceiling fans combining modern design with advanced performance.
High-quality commercial fans from Taiwan with advanced cooling efficiency.
Premium ceiling fans from Taiwan, built for durability and performance.
HVLS fans generate a large column of slow-moving air that increases convective heat loss from animal skin surfaces — the same mechanism as wind-chill. Increasing air velocity from near-zero to 1.5–2.5 m/s over the animal zone reduces perceived temperature by 4–8°C, significantly reducing heat stress indicators such as panting, feed refusal, and reduced daily gain.
No — provided fans are run at low speed during the brooding phase. Hamilton Air PMSM HVLS fans offer smooth 0–100% variable speed control, allowing operators to start at 20–30% speed during the first two weeks, then gradually increase as animals grow and heat sensitivity shifts. At low speed, air movement is gentle and silent — far less disruptive than the start-stop cycling of conventional exhaust fans.
Yes. Continuous air circulation dilutes ammonia concentrations near the floor and animal zone. Better air circulation also promotes faster litter drying, which directly reduces ammonia generation at the source. Farms using HVLS ventilation typically report 30–50% lower ammonia levels compared to stagnant barn conditions — improving both animal lung health and regulatory compliance for occupational safety.
Yes — and this is the optimal configuration. HVLS fans excel at improving air distribution and eliminating dead zones within a tunnel-ventilated structure. They complement longitudinal airflow from tunnel fans by generating a downward and outward column that reaches the animal zone more effectively, especially in wide-span buildings where tunnel airflow loses velocity near the sidewalls and beyond 60m from the inlet.
Hamilton Air PMSM HVLS fans require annual blade inspection, blade bolt torque check, and bearing lubrication — typically completed in under 90 minutes per fan. The motor itself is sealed (IP55–IP65) and requires no internal maintenance. Blade surfaces may be wiped clean during routine washdown cycles. There is no gearbox oil to change, no brushes to replace, and no commutator to service — making HVLS fans far lower maintenance than the conventional axial and exhaust fans they replace.
Also in this environment
Humidity & temperature control to prevent spoilage and mould
Air circulation to maintain uniform pre-cooling and shelf life
Worker comfort and corrosion prevention in machinery storage
Gentle air movement for transpiration management
IP65 rated fans for high-humidity aquaculture buildings
Precision humidity uniformity to prevent hot-spot contamination
Ready to protect your flock?
Our agricultural ventilation specialists will visit your farm, map airflow dead zones, calculate heat stress reduction, and design the optimal HVLS configuration — at no cost for qualifying projects across Vietnam.
