How to Install Evaporative Cooling Pads in a Poultry House: Step-by-Step Guide

When outdoor temperature climbs past 32°C, a poultry house without evaporative cooling delivers inlet air at nearly the same temperature as outside. Birds then eat less, shell quality drops, and mortality rises in severe cases. The proven fix is a pad-and-fan system: wet cellulose pads on the inlet wall, exhaust fans pulling air through them, and the temperature of incoming air dropping by 10–15°C whenever humidity is low enough. The result, however, depends on installation. Wrong pad area, gaps around the media, or uneven water flow will create hot spots, shorten pad life, and raise electricity bills. This guide walks through the complete installation process, with the measurements and tolerances that separate a good system from an average one.

How Evaporative Cooling Works in a Poultry House

Evaporative cooling relies on negative pressure. Exhaust fans at one end of the house pull air out, and outdoor air enters through wetted honeycomb pads at the opposite end. As the air passes through the wet media, water evaporates, absorbing heat and lowering dry-bulb temperature. The cooled air then travels down the house, picking up heat and moisture from the birds before the fans push it outside.

Two constraints determine whether this works well. First, airflow must be uniform across the entire pad face. If some areas draw more air than others, dry zones form and cooling drops in those spots. Second, the house must not be too long. The optimal tunnel length is around 80 meters and 120 meters is the practical maximum. Beyond that, the air warms noticeably by the time it reaches the far end, and hot spots appear regardless of pad quality.

The chart shows the central trade-off. Raising face velocity increases total airflow but reduces the temperature drop per cubic meter of air. For broiler and layer houses, 1.5–2.0 m/s keeps efficiency in the 70–80% range while still providing enough air exchange. The staggered honeycomb structure inside the pad is what makes this performance possible; see the advantages of honeycomb cooling pads over traditional cooling methods for a closer look at the geometry.

Calculate Pad Area and Select the Right Pad

Pad area comes first because it determines everything else: frame length, water flow, pump size, and even fan selection. The calculation is straightforward:

Pad area (m²) = total fan airflow (m³/s) ÷ target face velocity (m/s)

Take a typical 1,000 m² broiler house moving 250,000 m³/h (69.4 m³/s) of air. At a target face velocity of 1.8 m/s, the required pad area is 69.4 ÷ 1.8, or about 38.6 m². With a pad wall 1.5 meters high, that translates to roughly 26 meters of pad length. Halve the pad area and face velocity doubles to 3.6 m/s; efficiency then falls below 50% and the birds notice almost no relief.

Pad thickness is the second decision. A 150 mm cellulose pad is the standard for poultry because it balances airflow resistance against moisture retention. The 100 mm option cools less, and 200 mm media adds static pressure that costs fan energy for only one or two degrees more cooling. For most poultry houses, the 6090 poultry equipment cooling pad is the practical choice: its fluted honeycomb structure holds water evenly across the face while draining fast when the pump stops.

6090 Poultry Evaporative Cooling Pad with Honeycomb StructureThis 6090 pad offers a balanced cooling solution for poultry houses, with fluted honeycomb media that distributes water evenly and drains quickly, making it a practical pick for standard installations.View Product →

Step-by-Step Installation Process

Step 1: Build the Supporting Frame

The frame carries the weight of wet pads plus recirculating water, so it needs to be stiff. Galvanized steel or treated aluminum sections are standard; untreated timber rots quickly in the humid inlet zone. The frame top holds the distribution pipe, the bottom forms a collection gutter, and the sides keep the pad panels vertical and square. A pre-engineered honeycomb pad frame removes most alignment errors because the slots are formed to the exact pad thickness.

Honeycomb Evaporative Cooling Pad with Supporting FrameThis product pairs the honeycomb pad with a pre-engineered frame, reducing alignment errors during installation and helping ensure proper vertical flutes and tight panel fits for effective cooling.View Product →

Step 2: Mount the Cooling Pads

Always orient the flutes vertically. Water must run straight down the channels; horizontal or mixed flutes create saturated patches and dry streaks. Fit each panel snugly against the next because a 5 mm gap between panels lets hot air bypass the media and visibly reduces cooling at that location. Use closed-cell foam strips along the frame edges, but do not over-compress the pad. Crushing the flutes blocks both air and water flow.

Step 3: Install the Water Distribution System

Water enters at the top through a header pipe with holes or nozzles spaced 50–100 mm apart. The pipe should be level left to right and slope slightly toward the drain end so it empties completely when the pump stops. Stagnant water in a warm inlet area is the starting point for algae. On long pad walls, a perforated spreader tray or fabric wick between the pipe and the pad top improves wetting uniformity.

Step 4: Set Up the Sump and Pump

The sump sits below the pad wall and collects recirculating water. Size it so the pump inlet stays submerged even when the system has just been switched off and all the water in the pad channels drains back into the sump; a volume equal to roughly two minutes of full pump flow is a practical minimum, and a deeper sump also keeps water temperature more stable. Choose a pump that delivers at least 60 L/min per square meter of pad face at the required head. Install a strainer on the suction line in a location where you can reach and clean it easily, since that screen needs the most regular attention.

Step 5: Position the Exhaust Fans

Fans go on the end wall or on the side walls near the far end, spaced evenly to keep negative pressure uniform across the pads. Total fan airflow should match the pad area calculation; fans that exceed the design face velocity add static pressure, wear out belts faster, and consume more electricity. After installation, tune the system with a pressure gauge or a smoke test to confirm that air is drawn evenly through the entire pad face.

Water Quality, Bleed-Off, and Maintenance

A good installation survives or fails on water management. Hard water deposits calcium carbonate inside the pad channels, and one summer of heavy scale can cut cooling efficiency in half while shortening pad life from five years to two. The standard countermeasure is bleed-off: deliberately draining a small portion of the recirculating water and replacing it with fresh water so minerals never concentrate.

Algae is the second problem. The simplest preventive measure is to let the pad surface dry completely at least once a day: run the fans for 20–30 minutes with the pump off after the hottest hours. Shading the pad face from direct sunlight also slows algae growth. In dusty areas, check the air-entry side of the pads monthly and wash out clogged channels with a low-pressure water jet.

Common Installation Mistakes and Their Consequences

When a poultry pad system underperforms, the cause is rarely the pad material. It is one of five fixable design or installation decisions, and the pattern is consistent across farms.

1. Undersizing the pad wall. Saves money upfront but doubles face velocity, pushes efficiency below 50%, and leaves birds panting on the hottest days. Add 10–15% margin to the calculated area.
2. Leaving bypass gaps. Every perimeter joint must be sealed. Air that slips around the pads is unfiltered and uncooled, and it raises bird-zone temperature more than most farmers realize.
3. Distributing water unevenly. A header pipe with plugged nozzles leaves dry streaks down the pad. Inspect and clean the holes before each season.
4. Skipping bleed-off on hard water. Scale forms within weeks. A simple float valve and bleed line protect the pad investment for years.
5. Mismatching fans and pads. Fans that overwhelm the pad area create high static pressure, belt wear, and wasted energy without delivering more useful cooling.

Frequently Asked Questions

What size evaporative cooling pad do I need for a 1,000 m² poultry house?

Divide the total installed fan airflow in m³/s by 1.8 m/s. A typical 1,000 m² house moves 250,000–300,000 m³/h, so the pad area works out to roughly 38–46 m², or a 1.5 m high pad wall about 26–30 meters long.

Should I choose a 100 mm or 150 mm pad?

Use 150 mm for most poultry installations. It delivers roughly 3°C more temperature drop than 100 mm media at the same face velocity, with only a small increase in airflow resistance. The 200 mm option is rarely worth its extra static pressure in poultry barns.

Can I install the system myself, or do I need a contractor?

Most farm crews can install a pad-and-fan system with basic metalwork and plumbing skills. The steps that need care are frame alignment, perimeter sealing, and pump sizing. If you are retrofitting an existing building, ask a ventilation consultant to confirm the fan-and-pad calculation before spending money. For retrofit projects with tight spaces, modular pads such as the 5090 honeycomb cooling pad are easier to handle than long continuous sections.

5090 Modular Honeycomb Cooling Pad for RetrofitsIdeal for retrofitting tight spaces, this modular 5090 cooling pad is easier to handle than long continuous sections, and its replaceable media suits systems with soft water and bleed-off for long service.View Product →

How often should pads be replaced?

With soft water and a working bleed-off system, a quality cellulose pad lasts five years or more. On hard water without bleed-off, budget for replacement every two years. Replace pads when the flutes collapse, when the media feels brittle, or when cleaning no longer restores airflow and temperature drop.

Should the water pump run continuously?

No. Run the pump only while the fans are operating, and at the end of each cycle let the fans dry the pads for 15–30 minutes with the pump off. That drying period controls algae, limits mineral buildup, and extends pad service life.

An evaporative cooling system is only as good as its installation. Calculate the pad area from real fan airflow, keep face velocity near 1.8 m/s, seal every joint, and manage water with bleed-off plus a daily drying cycle. Do that consistently and a quality cellulose pad will deliver reliable cooling for five years or more. If you need a layout for your specific house, contact our team to review your house dimensions, fan capacity, and water source before you place an order.