Frequently asked questions about HEPWORTH heating pipes
Common Questions About HEPWORTH Heating Pipes – Expert Answers from Practice
HEPWORTH pipes are among the most widely used plastic pipe systems for heating in the Slovak market. Despite their popularity, the same questions keep arising with every project – from first-time heating installers, and to some extent also from experienced plumbers switching from copper or steel pipes to plastics. This article gathers the most frequently asked questions from practice and answers them thoroughly, with specific numbers and examples – so that after reading it, you will truly know what you are buying, how it works, and what to avoid.
What exactly is HEPWORTH pipe and why is it so widespread?
HEPWORTH is a British manufacturer (now part of the Wavin group), best known for its plastic water and heating pipe systems. In the Slovak and Czech markets, the name has become synonymous mainly with polybutylene (PB) pipes and related systems for hot water and heating distribution. The term “HEPWORTH” is used somewhat informally here – customers use it to refer to the entire group of plastic pipes for heating, including HEP2O (cross-linked polyethylene – PEX) and classic PB pipes.
The reason for its popularity is simple: it is a system that combines flexibility (easy handling, fewer joints), resistance to temperature and pressure, long service life, and relatively simple installation. Unlike copper, it does not require soldering, and unlike steel pipes, it does not corrode. For domestic installations with a hot water boiler or heat pump, it is an excellent choice in terms of performance, cost, and ease of installation.
The most commonly used dimensions in heating systems are 15 mm, 22 mm and 28 mm. Each of them has its typical application – this is discussed in more detail in another article in our Knowledge Centre (What pipe diameter do I need for heating: 15, 22 or 28 mm).
Is HEPWORTH pipe suitable for all types of heating?
This is one of the most frequently asked questions we receive. Short answer: yes, but with conditions. Let’s break them down.
Hot water heating (radiators, underfloor heating): Here, HEPWORTH pipes are right at home. Operating temperatures up to 90–95 °C and operating pressure up to 6 bar are values that typical domestic heating systems are far from reaching. Boilers usually set the water temperature to 50–80 °C, and the pressure in the system is around 1.5–2.5 bar. So, from a technical standpoint, the use of plastic HEPWORTH pipes is perfectly fine.
Underfloor heating: It fits very well – the flexibility of the pipes makes it easier to create loops in the floor, and no additional joints in the concrete are needed. Here, the 15 mm dimension in coiled form is typically used.
High-temperature systems (e.g., hot air heating units, industrial piping): If the temperature of the heat carrier consistently exceeds 90 °C or the pressure exceeds 6 bar, HEPWORTH plastic pipes are not the right choice. For such applications, copper or steel remain the best options.
Heat pumps: Most heat pumps operate with an output temperature of 35–55 °C (low-temperature systems). This is an ideal environment for HEPWORTH pipes.
Solar collectors: Be careful here. Some solar systems can reach temperatures of up to 120–150 °C (stagnation), which would damage plastic pipes. In general, plastic pipes are not recommended for the primary circuit of solar collectors.
What is the difference between coils and straight lengths – and when to use which?
HEPWORTH heating pipes are available in two basic formats: coils (spools) and straight lengths (sticks). This question comes up very often, and the choice has a real impact on the speed of installation and the final cost of the installation.
Coils are ideal for long continuous runs without a large number of elbows and branches – typically underfloor heating, supplying distant parts of the house, or feed to a manifold from the boiler room. The advantage is a minimal number of joints (each joint is a potential weak point), quick installation on long runs, and the ability to bend the pipe directly on site without elbows.
Sticks (straight pieces) are suitable where regular connections and branches to radiators are needed, or in spaces with fixed obstacles (doors, windows, stairs). Less material is wasted with sticks, as you can cut them to exact size. They are also stiffer – better for running straight pipes in grooves or along walls.
Available variants: HEPWORTH heating pipe in sticks, 15 mm and HEPWORTH heating pipe in sticks, 22 mm are the most commonly chosen dimensions for radiator distribution in stick format.
A more detailed comparison of both formats with practical examples can be found in the article HEPWORTH pipe in coils vs. in sticks – which to choose in our Knowledge Centre.
What dimensions (diameters) are used in practice and how to choose the right one?
This is another classic question. The pipe diameter directly determines how much water (heat carrier) the system can transfer per unit of time at a given pressure and temperature. A poorly designed diameter means either insufficient performance (too small a pipe – high pressure loss) or unnecessarily high cost and material waste (too large a pipe).
As a practical orientation:
- 15 mm – used for connecting individual radiators (so-called last branch), underfloor heating, and distribution routes for smaller areas (up to approx. 100–120 m² with standard insulation). Practical example: a family house of 80 m², 6 radiators – the entire distribution system can be in 15 mm. Available as HEPWORTH Pipe, Heating, 15 mm in coils.
- 22 mm – main distribution branches for larger houses (130–250 m²), connection to a manifold, primary circuit in cascade boiler connections. Example: a two-story house, boiler room in the basement, main vertical distribution in 22 mm with 15 mm branches to radiators. Available as HEPWORTH Pipe, Heating, 22 mm.
- 28 mm – larger buildings, or the primary circuit of a larger heat pump, boiler rooms for apartment buildings or commercial properties. In family houses, 28 mm is less common – mainly used for boiler-storage or boiler-manifold connections at outputs above 25–30 kW. Available as HEPWORTH Pipe, Heating, 28 mm.
Precise hydraulic calculations for selecting the correct diameter are part of the heating system design. In practice, however, most designers for family houses follow the rule: 15 mm for branches to individual units, 22 mm for distribution circuits, and 28 mm only for boiler circuits at outputs above approx. 20 kW. More in the article What pipe diameter do I need for heating: 15, 22 or 28 mm.
How is HEPWORTH pipe connected – what types of connections are available?
Connecting HEPWORTH plastic pipes is one of the most important technical topics, as the connection determines the tightness of the entire system. There are several methods:
1. Press (crimp) connections: The most common method today for heating distribution. Uses presses for TH, V or M profiles (depending on the manufacturer of the fittings). Crimping is fast, reliable and does not require any adhesives, soldering or open flame. Advantage: the connection is immediately secured and tight, can be visually and instrumentally checked. Disadvantage: you need a crimping tool (manual or electric) – for larger projects it is worth renting or buying.
2. Threaded (compression) connections: Mechanical threaded fittings – the pipe is inserted into the fitting and tightened with a wrench. Advantage: no special tools are required. Disadvantage: long-term tightness depends on correct tightening and quality of O-rings, and the sealing wears out when disassembled and reassembled.
3. Electrically welded (electrofusion) connections: Used in some PB or PEX systems, electrofusion fittings with an embedded resistance wire melt the plastic and weld the joints together. Advantage: extremely strong and durable connections. Disadvantage: cost of the tool, time and the need to strictly follow the procedure.
For standard home heating with HEPWORTH pipe, crimping is the standard, or a combined approach: crimped fittings for hidden distribution, threaded for visible or easily accessible areas. A detailed step-by-step installation procedure can be found in the article Installation of HEPWORTH pipe for heating step by step.
Can HEPWORTH pipe replace copper or steel?
This is a question that divides installers and customers. Technically speaking: yes, for the vast majority of domestic heating applications, HEPWORTH plastic pipe can fully replace copper or steel. Here are specific comparisons:
Compared to copper: Plastic pipe is cheaper (copper prices have risen significantly in recent years), easier to install (no soldering, flame or flux required), does not require special protection when passing through concrete or masonry, and is not subject to electrolytic corrosion in mixed systems. On the other hand, copper can withstand higher temperatures and pressures, is stronger and has less thermal expansion.
Compared to steel pipes (black steel, galvanized steel): Plastic does not corrode (a huge advantage in heating systems with inhibitors), is easier to install, does not require threading or welding, is lighter and easier to handle. Steel pipes have higher mechanical strength and can withstand higher pressure.
Practical example: a customer renovated an old panel apartment with original steel pipes. A complete replacement with HEPWORTH pipe in 15 mm and 22 mm reduced the installation time by a third, the material cost was comparable, but the labor was cheaper (fewer joints, no welding). The system has been working without problems for years.
How does HEPWORTH pipe behave with temperature changes?
Plastic pipes have a significantly higher coefficient of thermal expansion than copper or steel. This is a topic that installers sometimes forget, and then wonder why the pipes "wave" when heated or why stress appears at the joints.
The linear thermal expansion coefficient of polybutylene (PB) is approx. 0.13 mm/m/°C. This means that a 10-meter section of pipe at a temperature increase of 50 °C (e.g. from 20 °C to 70 °C) will extend by:
10 m × 0.13 mm/m/°C × 50 °C = 65 mm
That is almost 7 cm! If the pipe is rigidly fixed at both ends without compensation, enormous mechanical stress occurs in it. Solutions:
- Leave free sliding supports on long straight runs and fixed supports at only one location (so-called fixed point + sliding points)
- Build in compensating loops (U-loops or L-compensations in corners)
- Use changes in the direction of the distribution (every corner naturally compensates for expansion)
- Hidden distribution in grooves or in the floor is less problematic, as concrete/plaster mechanically limit movement – it is, however, important to use protective sleeves (protectors)
This is one of the most common mistakes in the installation of plastic pipes in general – neglecting the compensation for thermal expansion. Learn more about typical mistakes in the article Common mistakes in the installation of plastic pipes for heating.
What is the lifespan of HEPWORTH heating pipes?
The manufacturer states the lifespan under design conditions (temperature, pressure) to be 50 years. Although this is a marketing figure, it is based on real tests according to the standard EN ISO 15875 (for PEX) or EN ISO 15876 (for PB) – where pipes are tested under extreme conditions and the results are extrapolated for long-term load.
From practice: installations from the 90s of the last century (about 25–30 years old) are still functioning without visible problems. Failures occur more often due to violation of technological conditions – excessively high temperature, mechanical damage, incorrect joints or faulty installation.
Factors that shorten the lifespan: temperatures exceeding the limit (over 90 °C), aggressive medium (for example, compatibility must be verified with certain types of antifreeze), UV radiation (plastic pipes must not be permanently exposed to the sun without protection), mechanical damage during installation (sharp bends, scratches).
More about maintenance and lifespan is covered in a separate article HEPWORTH heating pipes – maintenance and lifespan.
What is the difference between HEPWORTH and HEP2O?
This is a tricky question, because both brands come from the same manufacturer and both systems are plastic pipes for heating. The difference is in the material and construction:
HEPWORTH (PB – polybutylene): Softer, more flexible material, easier to bend even in winter, joining with crimped fittings is simple. Suitable for heating and for the distribution of potable water.
HEP2O (PEX-b – cross-linked polyethylene): Stiffer material, higher chemical resistance, in practice it is used much more often for the distribution of cold and hot potable water. It works just as well for heating. More information can be found in the article Difference between HEPWORTH and HEP2O pipes for heating.
Practical tip: if you are installing a system where you want to use one pipe for heating and for the distribution of water (for example, in a cottage or in a simpler installation), the HEP2O pipe is suitable for both circuits at once. More in the article Using HEP2O pipe for heating and water distribution in one system.
Can HEPWORTH pipe be covered with plaster or embedded in concrete?
Yes, but with conditions. This is an important practical topic for everyone who is renovating or building and planning hidden piping.
The following rules apply to covering with a groove in the wall or embedding in concrete mortar:
- The pipe must be run in a protective sleeve (flexible or rigid), which allows thermal movement and at the same time protects it from mechanical damage from plaster/concrete
- The sleeve must extend beyond each side of the expansion joint (e.g. from a concrete slab to a wall)
- In no case should the joint (fitting) be placed in the embedded part – all joints must be accessible
- Before covering, a pressure test (hydrostatic test) must be performed: pressurize the system to 1.5 times the working pressure (at least 6 bar for domestic heating) and leave it for 30 minutes to 1 hour – monitor whether the pressure drops
- When pouring the floor, the pipe must be filled with water or compressed air at the test pressure to prevent deformation by the concrete pressure
Why does HEPWORTH pipe sometimes make noise or crack?
Cracking and noise are among the most common complaints after installation. In the vast majority of cases, it is thermal expansion in combination with incorrect fastening.
Specific scenarios from practice:
Cracking when heating: The pipe elongates and friction against the fastening clamps or the groove in the wall causes a characteristic cracking sound. Solution: loosen the clamps, use sliding (not fixed) fasteners on long runs, or insert an insulating strip between the pipe and the fastener.
Noise from flow (water noise): Excessive flow speed due to insufficient diameter. Water in the pipe should not flow faster than about 0.5–1 m/s for heating (depends on power and diameter). Solution: use a larger diameter or install balancing valves.
Knocking (water hammer): Rapid closing of thermostatic heads or valves can cause water hammer. Solution: slower closing of valves (thermostatic heads with slow movement), expansion tank of the correct size.
More about faults can be found in the article Why the pipe leaks or cracks – common faults.
How many meters of pipe do I need – how to estimate it?
One of the most common questions when ordering. Since the pipe is sold in coils (50 m, 100 m) or in rod pieces (usually 3 m or 6 m), it is important to estimate the consumption so that you do not end up with a shortage in the middle of the work or buy too much unnecessarily.
Estimation procedure:
- Measure the routes on the floor plan or directly on the building – for each circuit separately
- Add vertical routes (risers, lowering to radiators)
- Add 10–15 % reserve for losses during cutting, measurement inaccuracies and expansion loops
- For floor heating, the rule of thumb is: with a 150 mm spacing of pipes, you need about 6.7 m of pipe per m² of area, with a 200 mm spacing about 5 m/m²
Example: an apartment of 60 m² with floor heating, spacing 150 mm: about 60 × 6.7 = 402 m of pipe + 10 % reserve = about 440 m. In this case, you would buy, for example, 5 coils of 100 m each, with the remainder used for connecting distributors, etc.
Can I use HEPWORTH pipe with antifreeze?
Yes, but not with every type. Plastic pipes are generally compatible with propylene glycol antifreezes (so-called ecological, green, with type D or PG marking). More problematic are ethylene glycols (type E) – it is necessary to verify compatibility with the manufacturer of the specific pipe and fittings.
Absolutely do not use: automotive coolant (contains additives for metal engines and can damage plastics and seals), cheap unbranded mixtures, liquids with amine-based inhibitors (can react with some plastics).
Practical tip: always use antifreeze certified for plastic systems and when ordering, verify compatibility with the pipe system manufacturer. The concentration of the mixture must correspond to the lowest expected temperature in the system – not "the more, the better", because too high a concentration increases viscosity and reduces heat transfer.
FAQ – Frequently asked questions and short answers
Can I install HEPWORTH pipe myself, without a professional?
The law does not explicitly prohibit installation for personal use, if it is a closed heating circuit (not the primary gas distribution). However: the pressure test and commissioning should be documented. If the boiler is connected to gas and boiler service requires authorization, we recommend calling a professional at the first start-up. For floor heating with poured underfloor, professional installation is absolutely recommended. A mistake embedded in concrete is very expensive to fix.
What tools do I need to install HEPWORTH pipe?
For crimped joints: a crimper (manual or electric), suitable jaws for the given profile type (TH, V or M), a pipe cutter (rotary – not a saw, to ensure a perpendicular cut without burrs), a depth insertion gauge, and possibly an expander for some systems. For threaded joints, a wrench and a cutter are sufficient. You can rent a crimper at some hardware stores or heating equipment retailers.
What to do if HEPWORTH pipe leaks after installation?
First, identify the location: whether it is a leaking joint or a cracked pipe. For crimped fittings, check whether the joint was properly crimped (visible crimp mark on the fitting after crimping). For threaded joints, carefully tighten the nut. If the pipe itself is leaking (crack), that section must be replaced – plastic pipes cannot be glued or soldered. In an emergency, you can use temporary repair clamps, but not as a permanent solution. For a temporary repair of the supply circuit, close the corresponding valve and call a professional as soon as possible.
Is HEPWORTH pipe suitable for cold drinking water as well?
It depends on the specific type of pipe. Pipes marked as "heating" are tested and certified for a closed circuit with a heat carrier – not for drinking water. For drinking water, the pipe must have certification according to the EN ISO 15875 or EN ISO 15876 standard and a hygiene certificate for contact with drinking water. Before using any pipe for drinking water, check the certification on the label or the manufacturer's technical data sheet. The HEP2O system is typically certified for drinking water as well – see the article Using HEP2O pipe for heating and water distribution in one system for more details.
Where to buy HEPWORTH pipe in Slovakia – what to look for when purchasing?
When purchasing, pay attention to: the size marking (outer diameter × wall thickness, e.g. 15 × 1.5 mm or 22 × 2 mm), material (PB or PEX-b), certification for the intended application, compatibility with fittings you plan to use, and whether the product is original with the appropriate documentation. Be cautious of cheap unnamed products – for underfloor heating, it is worth investing in proven systems. In the category heating pipes, you will find a verified selection with complete documentation.
Can I combine different diameters in one system?
You not only can – you almost always have to. A properly designed system narrows from the heat source (boiler) towards individual radiators. A typical combination is 28 mm from the boiler, 22 mm for main branches, and 15 mm for connecting radiators. Transitions between diameters are ensured by reducers, which are part of every complete fitting system. It is important to follow hydraulic sizing – unnecessary narrowing causes high pressure loss, while unnecessary widening results in slow flow and sedimentation.
Conclusion – what to take away from this article
HEPWORTH heating pipes are proven, long-term reliable products with a long service life, provided they are properly designed, installed, and operated. Most problems customers encounter actually have simple causes: incorrectly selected diameter, neglecting thermal expansion, improper joining procedures, or using low-quality fittings.
If you are unsure about selecting the correct diameter or format of pipe for your specific situation, check out other articles in our Knowledge Centre – for example, How to choose the right HEPWORTH pipe for heating, where you will find a systematic procedure from boiler output to the final selection of dimensions. To compare products directly in the online shop, visit the category heating pipes, where you will find the entire available range, including HEPWORTH 22 mm pipe and HEPWORTH 28 mm pipe for larger systems.
Do you have a question about this topic?
Having trouble deciding or dealing with a specific situation in your home? Write to us – we are happy to help.