Factory PE-RT (EVOH) Pipes for Greenhouse Heating: Selection and Installation Guide

For greenhouse heating, I recommend selecting PE-RT (EVOH) pipe by matching the pipe’s temperature rating, pressure class, oxygen-barrier construction, dimensions, and installation method to the actual heating system. A factory-produced PE-RT (EVOH) pipe is typically a multilayer pipe with PE-RT carrying layers and an EVOH barrier layer that helps limit oxygen permeation into closed hydronic heating circuits. The correct choice depends on water temperature, operating pressure, pipe spacing, heat-source design, connection method, and local project requirements.

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At HTIAN, we help agricultural buyers evaluate Factory PE-RT (EVOH) Pipes for greenhouse heating applications, including product configuration, sizing discussions, packaging, and export coordination. Because every greenhouse has different climate conditions and heat loads, I treat published specifications as a starting point rather than a substitute for hydraulic and thermal design.

Who This Guide Is For

This guide is intended for greenhouse owners, agricultural contractors, heating-system integrators, distributors, and procurement teams sourcing PE-RT (EVOH) pipes from a factory. It is especially useful when the project uses hot-water circulation for root-zone heating, bench heating, perimeter heating, snow melting, or general greenhouse temperature control. It can also support buyers comparing multilayer heating pipes with conventional PE-RT, PEX, or other polymer pipe options.

I recommend involving a qualified heating designer when the project includes a large boiler plant, heat pump, thermal storage tank, antifreeze, high static pressure, or multiple temperature zones. The pipe should be selected as part of a complete system rather than purchased only by outside diameter or price.

What PE-RT (EVOH) Pipe Does in a Greenhouse Heating System

PE-RT is a polyethylene material designed for elevated-temperature pressure applications. In a greenhouse heating circuit, it carries heated water from a heat source or manifold to heating loops and returns cooler water to the system. The pipe’s flexibility can simplify routing around growing areas, benches, support structures, and service corridors.

The EVOH layer functions as an oxygen-barrier layer in the pipe wall. In a closed hydronic system, limiting oxygen entry can help reduce the conditions that contribute to corrosion of metallic components such as boilers, pumps, valves, and heat exchangers. The actual barrier performance must be confirmed from the manufacturer’s technical documentation and the applicable product standard.

Typical Construction and Material Options

Many PE-RT (EVOH) pipes use a three-layer structure: PE-RT inner layer, EVOH barrier layer, and PE-RT outer layer. Some products use adhesive or bonding layers between the polymer and barrier materials, so I advise buyers to request a cross-section description instead of assuming that all multilayer pipes have identical construction.

Material selection should also consider the heating medium. Clean water, treated water, and water mixed with glycol may create different compatibility requirements. If antifreeze is planned, the buyer should confirm concentration limits, temperature conditions, and chemical compatibility with the pipe, fittings, seals, and other system components.

Key Specifications to Confirm Before Ordering

I suggest preparing a technical checklist before requesting a factory quotation. The most important information includes outside diameter, wall thickness, pressure rating, temperature rating, EVOH barrier structure, coil length, fitting system, color, packaging, and applicable testing or compliance documents.

For example, a quotation may specify a 20 mm outside diameter pipe, but that figure alone does not establish flow capacity or pressure performance. Wall thickness and internal diameter must also be reviewed. I also recommend confirming whether the stated pressure rating applies at the intended water temperature and whether the product is designed for continuous heating service.

How to Match the Pipe to Greenhouse Applications

Root-Zone and Bench Heating

Root-zone and bench heating normally require controlled, even heat distribution close to the plants or growing media. Smaller pipe sizes may be practical for individual heating loops, while larger headers or manifolds are used to distribute water to several zones. The final pipe spacing and loop length should be calculated from heat demand, water temperature, flow rate, and allowable temperature variation.

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Perimeter and General Space Heating

Perimeter heating can help address cold zones near greenhouse walls, doors, and ventilation areas. General space-heating layouts may use overhead, wall-mounted, or low-level circuits depending on the greenhouse structure and crop arrangement. In each case, the pipe must be protected from abrasion, sharp edges, excessive ultraviolet exposure, and accidental impact from equipment.

High-Temperature or Mixed-Temperature Systems

A boiler may produce water at a higher temperature than the PE-RT circuit should receive. Where this occurs, a mixing valve, heat exchanger, buffer tank, or separate temperature-control zone may be needed. I do not recommend connecting polymer heating loops directly to a heat source until the system designer has verified the maximum temperature and pressure conditions.

Step-by-Step Selection and Installation Process

1. Define the system conditions. Record heat source, design water temperature, operating pressure, fluid type, indoor and outdoor temperatures, and the number of heating zones.
2. Estimate heat demand. Use the greenhouse size, crop requirements, insulation, ventilation, local climate, and desired indoor temperature. Pipe selection should follow the heat-load calculation.
3. Select pipe dimensions. Compare internal diameter, flow rate, pressure loss, loop length, and manifold arrangement. Do not select only by the lowest unit price.
4. Confirm the barrier and pressure structure. Request the layer construction, temperature-pressure data, dimensional information, and available quality documents from the factory.
5. Check fitting compatibility. Confirm whether the system uses press, compression, expansion, or another approved connection method. Use fittings intended for the exact pipe dimension and material system.
6. Plan the route. Keep loops supported, avoid tight bends below the stated minimum bend radius, and provide space for expansion, inspection, and maintenance.
7. Install and test. Flush the circuit, inspect joints, fill the system correctly, remove trapped air, and perform a pressure test according to the design specification and local requirements before covering or commissioning.

Installation conditions are important because polymer pipe can expand and contract as temperature changes. I advise installers to follow the manufacturer’s minimum bend radius and fixing guidance rather than applying a universal value. A practical project record should identify the test pressure, test duration, water temperature, and inspection results; these values must be set by the system designer or applicable installation standard, not guessed from a general online article.

Common Selection and Installation Mistakes

One common mistake is using a domestic plumbing specification for a greenhouse heating circuit without checking continuous temperature and pressure conditions. Another is treating the EVOH layer as a complete solution while ignoring unsuitable fittings, poor joint preparation, or corrosion-sensitive system components. Buyers should also avoid mixing pipe and fittings from different systems unless compatibility has been confirmed in writing.

Improper storage can create additional risk. Coils should be protected from contamination, crushing, sharp objects, and unnecessary sunlight exposure, while the pipe ends should remain capped where appropriate. During installation, excessive bending, dragging over rough surfaces, and placing pipe beneath heavy equipment can damage the pipe or reduce long-term reliability.

Factory Purchasing: Price, MOQ, Lead Time, and Support

Factory pricing for PE-RT (EVOH) pipes depends on resin specification, pipe size, barrier construction, coil length, color, packaging, order quantity, fittings, and inspection requirements. A low price may not represent the lowest total project cost if it requires special tools, nonstandard fittings, excessive joints, or short delivery quantities. I recommend requesting a complete commercial offer that separates pipe, fittings, packaging, tooling, shipping terms, and any customization.

MOQ and lead time should be confirmed before finalizing the greenhouse schedule. Standard sizes and standard packaging may be easier to supply than customized colors, printed markings, special coil lengths, or private-label packaging. For an agricultural project with seasonal installation deadlines, I suggest confirming production capacity, sample approval timing, inspection arrangements, and shipping documents in advance.

How to Evaluate a PE-RT (EVOH) Pipe Supplier

• Ask for a clear product datasheet covering dimensions, temperature, pressure, and layer construction.
• Confirm which fittings, tools, and joining instructions are supplied or recommended.
• Request samples when the project involves a new size, special barrier structure, or customized packaging.
• Check whether the supplier can support batch identification, inspection records, and export documentation.
• Compare production consistency, communication, packaging, and after-sales response—not only price.
• Verify that the proposed product is suitable for the planned heating medium and greenhouse environment.

As an agricultural piping supplier, HTIAN can discuss Factory PE-RT (EVOH) Pipes for greenhouse heating according to the buyer’s project conditions. Our support can include reviewing requested dimensions, pipe structure, fitting requirements, packaging preferences, and order logistics. Product availability, MOQ, lead time, and documentation should be confirmed for each quotation because they can vary by specification and order volume.

Key Takeaways for Greenhouse Heating Buyers

• PE-RT provides the temperature-resistant pipe structure, while EVOH serves as an oxygen-barrier layer in many multilayer designs.
• Correct selection requires temperature, pressure, flow, loop length, fluid, fittings, and installation conditions to be reviewed together.
• A three-layer PE-RT/EVOH/PE-RT structure is common, but buyers should confirm the exact construction from factory documentation.
• Installation quality, pressure testing, air removal, and protection from mechanical damage are as important as the pipe material.
• For procurement, request a project-specific quotation covering technical data, MOQ, lead time, packaging, fittings, and export support.

Conclusion: The Practical Next Step

Factory PE-RT (EVOH) Pipes can be a suitable option for greenhouse hydronic heating when the pipe construction, pressure-temperature performance, fittings, and layout are properly matched to the project. The EVOH barrier is particularly relevant when the heating system includes metallic components that require controlled oxygen ingress, but the complete system still needs correct water treatment, commissioning, and maintenance.

Before placing an order, prepare a project brief with greenhouse area, heating application, design water temperature, operating pressure, fluid type, required pipe sizes, estimated quantity, fitting requirements, destination, and target delivery date. Send these details to HTIAN for a more accurate product and commercial evaluation. This approach helps buyers compare suppliers on documented suitability, supply capability, and total project support rather than on pipe price alone.

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