Building a “Hi-Tech” Fan & Pad polyhouse in Bangalore is a waste of money. Building a “Net House” in heavy rainfall areas is a disaster.
“Nature doesn’t have bad weather, your crops just have the wrong protection.” Choosing the right structure is the most critical decision you will make. If you get this wrong, no amount of fertilizer or good seeds can save your crop.
In this guide, we compare the three major types of protected cultivation structures—Naturally Ventilated Polyhouse (NVPH), Fan & Pad (Climate Controlled), and Shade Net House—to help you decide which one matches your Budget and your Climate.
Naturally Ventilated Polyhouse (NVPH)
The “Gold Standard” for 70% of Indian Farmers.
This structure does not use exhaust fans or cooling pads. Instead, it relies on physics. It has roof vents (openings at the top) and side curtains. As hot air rises, it escapes through the top vent, while fresh air enters from the sides.
- Best For: Moderate climates (temperatures 15°C to 35°C).
- Cost (Approx): ₹800 – ₹950 per sq. meter.
- Electricity: Zero (for cooling).
- Crops: Capsicum, Cucumber, Tomato, Gerbera, Rose.
✅ Pros:
- Low operational cost (No electricity bill for fans).
- Low maintenance (No cooling pads to clean).
- Perfect for tropical areas with good wind flow.
❌ Cons:
- Cannot lower the temperature below the outside temperature. (If it’s 40°C outside, it will be ~38°C inside).
- Not suitable for extremely hot summers.
Fan and Pad Polyhouse (Hi-Tech)
The “Air-Conditioned” Factory.
This is a fully sealed structure. On one wall, there are wet Cellulose Cooling Pads (honeycomb structure). On the opposite wall, there are huge Exhaust Fans. When fans suck the air out, fresh air is pulled through the wet pads, cooling it down instantly.
You can think of a Fan & Pad polyhouse as a giant version of the domestic air coolers used in homes during the summer. Just like a home cooler, it circulates air through wet pads to create a refreshing, cool breeze for the plants.
- Best For: Hot and Dry climates (temperatures > 40°C) with low humidity.
- Cost (Approx): ₹1,600 – ₹2,000 per sq. meter.
- Electricity: High (Requires 3-Phase connection and generator backup).
- Crops: Exotic vegetables, Hydroponics, Nursery saplings.
✅ Pros:
- Can lower temperature by 10-15°C compared to outside.
- Complete protection from insects (completely sealed).
- Allows year-round production even in peak summer.
❌ Cons:
- Expensive to run: High electricity bills eat into profits.
- Ineffective in High Humidity: If the air is already humid (like in Mumbai/Chennai), the evaporative cooling won’t work well.
Shade Net House (Flat or Dome)
The “Budget-Friendly” Option.
This is not a “Polyhouse” because it doesn’t use polyethylene film. It uses a porous Net (Green or Black/White) to cut sunlight intensity by 50% or 75%.
- Best For: Dry areas with less rainfall.
- Cost (Approx): ₹350 – ₹550 per sq. meter.
- Electricity: Zero.
- Crops: Leafy greens, hardy vegetables, medicinal plants.
✅ Pros:
- Cheapest to construct and maintain.
- protects crops from scorching sun and birds.
❌ Cons:
- No Rain Protection: If it rains, water enters the structure. This causes fungal diseases (blight/rot) in crops like Capsicum.
- No Pest Control: Smaller insects can easily enter through the net mesh.
The Climate-to-Structure Map (Crucial Decision Tool)
Which Structure is Right for Your State?
A “Fan & Pad” polyhouse is a waste of money in Bangalore, but essential in Rajasthan. Use this map to choose:
| If you live in… | Your Climate is… | Recommended Structure | Why? |
| Rajasthan, Gujarat, North MP, Haryana | Hot & Dry (Summer > 42°C) | Fan & Pad Polyhouse | You need active cooling to lower temp from 45°C to 30°C. NVPH will fail here in summer. |
| Maharashtra (Pune/Nashik), Karnataka (Bangalore) | Moderate / Pleasant | Naturally Ventilated (NVPH) | Natural wind is enough to cool the crop. Fan & Pad is a waste of money here. |
| Kerala, Coastal AP, Konkan, West Bengal | Hot & Humid | NVPH (Top Vent) + Foggers | Fans fail in high humidity. You need high top vents (8 meters) for hot air escape. |
| Himachal, Kashmir, Uttarakhand | Cold / Snow | Fully Closed Polyhouse | You need to trap heat inside to protect crops from frost. No vents needed. |
Technical Specifications to check (Don’t Get Cheated)
When you finalize a structure, ensure your quotation includes these specs:
- Gutter Height: Should be at least 4 to 4.5 meters for NVPH. If it’s too low, heat will get trapped near the plants.
- Wind Resistance: Structure must withstand 120-140 km/hr winds. Ask for “wind bracing” support in the design.
- Cladding Material:
- Poly Film: 200 Micron, 5-Layer, UV Stabilized.
- Insect Net: 40 Mesh (Standard) or 50 Mesh (for Thrips protection).
- Shade Net: Thermal screens (Aluminet) are better than simple green nets for temperature control.
Naturally Ventilated (NVPH) vs. Fan & Pad: The Real Price Difference (2026)
Many farmers ask: “Why is the Fan & Pad polyhouse double the price?”
The difference isn’t just in the steel. It’s in the active machinery (Fans, Motors, Cooling Pads, Genset). Below is a side-by-side cost breakdown for a standard 1 Acre (4,000 Sq. Meter) project.
| Cost Component | NVPH (Standard) | Fan & Pad (Single Cladding) | Fan & Pad (Double Cladding) | Why the difference? |
|---|---|---|---|---|
| 1. Structure (Steel & Plastic) | ₹28 – ₹32 Lakhs | ₹44 – ₹50 Lakhs | ₹55 – ₹60 Lakhs | Fan & Pad needs a fully sealed structure + double cladding + stronger steel for fan vibration. |
| 2. Cooling System | ₹0 (Natural Wind) | ₹8 – ₹10 Lakhs | ₹8 – ₹10 Lakhs | Cost of 8-10 Exhaust Fans (50-inch) + Cellulose Cooling Pads + Water Pumps. |
| 3. Electrical Wiring & Panel | ₹50,000 | ₹2 – ₹3 Lakhs | ₹2 – ₹3 Lakhs | NVPH needs basic wiring. Fan & Pad needs heavy 3-Phase cabling and commercial control panels. |
| 4. Generator (DG Set) | Optional (Small) | ₹5 – ₹6 Lakhs | ₹5 – ₹6 Lakhs | Mandatory. If power fails for 1 hour in summer, crops inside a sealed Fan & Pad polyhouse will die. |
| 5. Civil Work (Tank/Room) | ₹3 – ₹4 Lakhs | ₹4 – ₹5 Lakhs | ₹4 – ₹5 Lakhs | Similar cost (Water tank + Control room). |
| 6. Micro Irrigation | ₹1.5 – ₹2 Lakhs | ₹2 – ₹2.5 Lakhs | ₹2 – ₹2.5 Lakhs | Fan & Pad often uses advanced foggers/misters for humidity control. |
| TOTAL PROJECT COST | ₹33 – ₹38 Lakhs | ₹75 – ₹85 Lakhs | ₹75 – ₹85 Lakhs | Fan & Pad is ~2.2x more expensive. |
The “Hidden” Running Cost
Construction is a one-time cost. Electricity bill is a monthly pain.
- Naturally Ventilated:
- Electricity Bill: ₹1,000 – ₹2,000 / month (Only for irrigation pump).
- Maintenance: Low (Cleaning gutters, tightening ropes).
- Fan & Pad:
- Electricity Bill: ₹25,000 – ₹40,000 / month (Fans run 8-10 hours/day in summer).
- Maintenance: High (Cooling pads need replacement every 3-4 years; Fans need greasing).
FarmAtma Verdict:
Unless you are in a very hot, dry region (Rajasthan/Gujarat) or growing exotic crops (Hydroponics/Orchids), the Fan & Pad structure is usually NOT financially viable for standard crops like Capsicum or Cucumber. The extra yield rarely covers the massive electricity bill.
✅ The Polyhouse Essentials Checklist
8 tools that separate profitable farms from struggling ones.
1. Crop Health & Monitoring
If you can’t measure it, you can’t manage it.
- 🧪 Waterproof EC/pH Pen
- Why: The most critical tool for hydroponics and soil. If you don’t measure conductivity (EC) and acidity (pH), you are flying blind on nutrition.
- FarmAtma Tip: Buy a “Combo Meter” that measures both.
- 🟡 Sticky Traps (Blue & Yellow)
- Why: Your early warning system. Yellow attracts whiteflies and aphids; Blue captures thrips. Use them to monitor pest density, not just to kill bugs.
- Rule: 1 sheet per 100 sq. meters.
- 🌡️ Min/Max Thermometer
- Why: You can’t be there 24/7. This simple digital device records the lowest night temps and highest day peaks so you can adjust your curtains or foggers accordingly.
2. Efficiency & Automation
Save labor costs with smart mechanics.
- 🧶 Roller Hooks (Trellising)
- Why: Stop tying knots manually. These pre-wound spools sit on overhead wires, allowing you to lower vining crops (tomatoes/cucumbers/capsicum) in seconds to keep them within reach.
- 💉 Venturi Injector
- Why: A low-cost, vacuum-based device that sucks fertilizer from a tank and mixes it directly into your irrigation line. Essential for consistent fertigation without needing expensive electric dosing pumps.
- ⏱️ Irrigation Timer
- Why: Consistency is king. Automated timers ensure crops are watered at the exact same time daily, improving root structure and saving you from hiring a laborer just to switch on a pump.
3. Maintenance & Safety
Be ready for emergencies.
- 🩹 UV-Stabilized Repair Tape
- Why: Regular cello tape melts in the sun. Keep a roll of specialized UV tape to patch accidental film tears immediately before high winds turn a small hole into a destroyed roof.
- 🌫️ Spare Fogger Nozzles
- Why: Misting nozzles have tiny holes that clog with calcium (scaling) quickly. Don’t try to clean them in the heat; swap them out instantly with spares and clean the dirty ones later in acid.
Conclusion: Which one should you build?
- For Beginners: Start with a Naturally Ventilated Polyhouse (NVPH). It balances cost and risk perfectly. It allows you to grow high-value crops like Capsicum without the headache of massive electricity bills.
- For Experts: If you are targeting a specific niche (like growing Strawberry in Rajasthan), go for Fan & Pad.
NEXT STEP: Now that you know which structure to build, find out how much it will cost.
👉 Read: Detailed Cost Breakdown of NVPH vs. Fan & Pad
(Ensure your vendor uses B-Class GI pipes and offers warranty)