Underfloor heating (UFH) systems have become increasingly popular in modern homes and commercial spaces, offering efficient, even warmth without the need for bulky radiators. At the heart of any wet UFH system are the pipes that carry heated water beneath your floors. Choosing the right type of pipe is crucial for performance, longevity, and cost-effectiveness. In this post, we'll dive into two common options: PEX-A pipes and PE-RT pipes. We'll outline their features, highlight key differences based on in-depth research, and also provide a detailed explainer on underfloor heating manifolds—a vital component often paired with these pipes. Finally, we'll showcase our range of high-quality offerings at Aizo Quality Heating to help you make an informed decision.
What is PEX-A Pipe for Underfloor Heating?
PEX-A, or cross-linked polyethylene type A, is produced using the peroxide cross-linking method, which creates a highly durable and flexible material. This cross-linking process enhances the pipe's molecular structure, making it ideal for demanding applications like underfloor heating.
Key features of PEX-A pipes include:
- Superior Flexibility: PEX-A is the most flexible among PEX variants, allowing for easy installation around bends and tight spaces without kinking. If a kink does occur, it can often be repaired using heat, reducing waste during setup.
- High Temperature and Pressure Resistance: These pipes can handle temperatures up to 95°C (203°F) or more, making them suitable for high-heat systems. They also resist bursting in freezing conditions due to their ability to expand.
- Durability and Longevity: With excellent corrosion resistance, anti-aging properties, and chemical stability, PEX-A pipes offer a long service life, often exceeding 50 years. Variants like PEX-AL-PEX include an aluminum layer for added oxygen barrier and heat distribution.
- Efficient Heat Transfer: The material promotes even radiant heating, contributing to energy savings.
- Installation Ease: Compatible with expansion fittings, which minimize leak risks in hard-to-reach areas.
PEX-A is particularly favored in UFH for its reliability in variable conditions, though it comes at a premium price due to the advanced manufacturing process.
What is PE-RT Pipe for Underfloor Heating?
PE-RT, or Polyethylene of Raised Temperature resistance, is a non-cross-linked polyethylene designed specifically for hot water applications. Unlike PEX, it relies on its molecular composition for enhanced performance without chemical cross-linking.
Key features of PE-RT pipes include:
- Good Flexibility and Lightweight Design: PE-RT is soft and easy to handle, making it suitable for long, continuous runs with minimal tools required. This reduces installation time and costs.
- Heat Resistance: It can withstand temperatures up to 80-95°C, depending on the grade, with strong creep resistance for sustained performance.
- Cost-Effectiveness: As a more affordable alternative to cross-linked options, PE-RT offers excellent value, especially for budget-conscious projects.
- Eco-Friendly and Corrosion-Resistant: Made from recyclable materials, it resists scaling, deposits, and chemical degradation. Multi-layer versions like PE-RT EVOH or PERT-AL-PERT add oxygen barriers for better system protection.
- Smooth Flow: The internal structure minimizes pressure loss and buildup, ensuring efficient water circulation.
- Versatility: Ideal for underfloor heating in residential and light commercial settings, with low environmental impact.
PE-RT shines in straightforward installations where cost and ease are priorities, though it may not match PEX-A's kink repairability.
Key Differences Between PEX-A and PE-RT Pipes
While both PEX-A and PE-RT are excellent choices for UFH, their differences stem from manufacturing processes, performance characteristics, and application suitability. Here's a breakdown:
| Aspect | PEX-A Pipe | PE-RT Pipe |
|---|---|---|
| Material Structure | Cross-linked via peroxide method (>70% cross-linking for superior density) | Non-cross-linked; relies on advanced polyethylene resins |
| Flexibility | Highest flexibility; kink-resistant and repairable with heat | Good flexibility for long runs; less forgiving with kinks |
| Temperature Resistance | Up to 95°C+; excellent for high-pressure systems | Up to 80-95°C; sufficient for most UFH but lower max than PEX-A |
| Durability | Superior resistance to bursting, aging, and chemicals; longer lifespan | Strong corrosion resistance and creep capability; reliable but potentially shorter in extreme conditions |
| Installation | Ideal for complex layouts with bends; uses expansion fittings | Easier for straight runs; lower processing costs |
| Cost | Higher upfront cost due to advanced production | More cost-effective; better for large-scale or budget projects |
| Oxygen Permeability | Low, especially in multi-layer variants (e.g., PEX-AL-PEX) | Very low in EVOH-layered versions; prevents system corrosion |
| Best For | High-demand installations requiring maximum reliability | Economical, eco-friendly systems with simpler designs |
Research from industry sources indicates that PEX-A outperforms in harsh environments, such as areas prone to freezing or high heat loads , while PE-RT is praised for its affordability and environmental benefits, making it a long-term investment in milder setups . Ultimately, the choice depends on your project's specifics—consult a professional for tailored advice.
Understanding Underfloor Heating Manifolds: An Essential Component
No discussion of UFH pipes is complete without covering the manifold—the "control center" of a water-based underfloor heating system. The manifold distributes heated water from your heat source (like a boiler or heat pump) through the pipes embedded in your floor, ensuring efficient and even warmth.
What is a Manifold?
A manifold is a hub that connects the primary heating circuit to multiple floor zones or circuits. It allows for independent temperature control in different rooms, optimizing energy use and comfort.
Main Components
- Flow Arms: Distribute heated water to individual circuits (each supporting up to 120 meters of pipe).
- Return Arms: Collect circulated water to return it to the heat source.
- Flow Meters: Adjust and monitor water flow rates for balanced heating.
- Valves: Control flow on the return side, often with actuators for automated operation.
- Air Vents and Gauges: Manual vents release trapped air, while combined pressure/temperature gauges monitor system performance.
- Accessories: Mixing units blend water to safe temperatures (20–60°C), isolation valves aid in filling/draining, and actuators (low-power, ~1W) respond to thermostat signals. Manifolds are often housed in wall cabinets for protection.
How It Works
Heated water enters the flow arm, optionally mixed for consistent temperatures. Flow meters ensure even distribution based on room needs and floor types. The water circulates through the pipes, radiating heat upward, then returns via the return arm. Thermostats signal actuators to open/close valves, heating zones on demand. This zoned approach prevents overheating and saves energy.
Installation and Maintenance Tips
Position the manifold centrally to minimize pipe lengths and ensure balanced distribution—use multiple manifolds for large or multi-floor properties. During setup, configure circuits considering heat losses, floor build-up, and outputs. For maintenance, regularly check gauges for proper temperature/pressure, vent air to avoid leaks, and verify actuator function. Pressure testing via isolation valves keeps the system reliable without downtime.
At Aizo Quality Heating, our Stainless Steel Underfloor Heating Manifold (2 to 12 Port Options) is built for durability and ease. Made from high-grade stainless steel, it resists corrosion and features adjustable flow meters, integrated valves, and compatibility with various pipe types. Available in configurations from 2 to 12 ports, it's perfect for small homes to large commercial spaces, ensuring seamless integration with your UFH setup.
Our Offerings at Aizo Quality Heating
We stock a range of WRAS-approved pipes designed for reliable underfloor heating performance. Whether you're opting for PEX-A or PE-RT variants, our products include multi-layer options for enhanced oxygen barriers and heat efficiency:
- UFH PERT-AL-PERT Pipe Coils for Underfloor Heating: A multi-layer PE-RT pipe with aluminum core for superior heat distribution and barrier protection.
- 16mm PEX-AL-PEX Pipe for Underfloor Heating: Durable PEX-A with aluminum layer, ideal for high-performance systems.
- 12mm PE-RT EVOH 3-Layer Pipe for Underfloor Heating: Compact, flexible PE-RT with EVOH barrier for smaller spaces and efficient flow.
- 16mm PEX-AL-PEX Pipe for Underfloor Heating: Our versatile 16mm PEX-A option, perfect for standard UFH installations.
All our pipes meet stringent UK standards for safety and efficiency. Pair them with our manifolds for a complete system.
In conclusion, whether you choose PEX-A for its robustness or PE-RT for its affordability, understanding these options ensures your UFH system delivers optimal comfort. If you need help selecting the right pipe or manifold, contact us at Aizo Quality Heating—we're here to guide you every step of the way!