District Heating

Download our guide to pre-insulated pipe and district heating

There are approximately 17,000 heat networks in the UK of which 5,500 are district heat networks and 11,500 communal heat networks.  Whilst these numbers sound impressive, heat networks still only contribute around 2% of the UK's total heat demand.

This guide aims to improve the industry's collective understanding of the heat network itself, addressing some of the most commonly-held misconceptions surrounding them in the process.

What is District Heating?

Currently in the UK the most popular heating system is an individual gas boiler, however this is not the most efficient heating method.  

District Heating is the concept of one large energy centre to provide the heat demand for a number of properties, residential, commercial or multi occupancy.

The Energy Centre can use a variety of heat sources such as fossil fuels (e.g. gas CHP), Energy from Waste, industrial waste heat or renewable energy sources such as heat pumps, biomass or anaerobic digestion to heat the water.

The hot water travels through an underground insulated pipe network to a heat interface unit (HIU) located in each building. This provides heating and hot water to each building which allows individual temperature control to each building.  The cold water then returns back to the energy centre to be heated and circulated again. 


Reduce CO2 Emissions

Save costs on maintenance and installation

Environmentally friendly

Carbon Reductions

- Significantly reduces CO2 emissions

through the local generation of heat

Cost Savings

- Lower maintenance Costs

- Lower costs to the end-user

- Significant installation cost savings over

steel pipes

Environmentally Friendly

-  Renewable energy can be used to

heat the network

- Possible to change the fuel source

- User independence and security of

energy supply.

RAUTHERMEX Pre-insulated PE-Xa pipe

RAUTHERMEX is a pre-insulated PE-Xa pipe district heating, biomass, biogas and heat pump applications. The high performance PU foam makes it ideal for large district heating over long distances where heat losses are critical. Lightweight polymer pipes such as RAUTHERMEX offer huge advantages over traditional steel pipework due to the speed and ease of installation.

RAUTHERMEX is available in UNO 25-160mm and DUO 20-75mm

RAUTHERMEX Plus also available.


  • Excellent thermal insulation with PU foam with a lambda value of 0.0216W/mK
  • New 140mm UNO is the largest polymer flexible district heating pipe on the market which can transport up to 2.5MW of heat at 80°C/50°C flow & return temperatures
  • No need to compensate for thermal expansion due to bonded foam structure
  • Long coils up to 570m possible, allowing for faster installations vs steel system in 12m lengths
  • Uses the renowned leak-proof REHAU EVERLOC™ compression sleeve technology, used over 850 million times
  • Generation II shrouds are quick and easy to install and remove the need for hot works on site
  • RAUTHERMEX Plus (with increased insulation thicknesses for up to 20% lower heat losses) available on request
  • Fully stocked in the UK with a full cutting service


  • RAUTHERMEX Strong is a 10 bar SDR 7.4 district heating pipe
  • Designed for higher pressure networks
  • RAUTHERMEX Strong is available in 25 - 63mm DUO and in coils from 75 - 400m
  • The 10 bar RAUTHERMEX Strong PE-Xa carrier pipe can be used n projects where there is a height difference from 30m to 70m on the heat network
  • RAUTHERMEX Strong pipes are self compensating in the ground

RAUVITHERM Pre-insulated PE-Xa pipe

RAUVITHERM is a pre-insulated PE-Xa pipe for district heating, biomass, biogas and heat pump applications.  It has proved immensely popular since its launch due to its high flexibility and easy to use REHAU EVERLOCTM jointing technology.

RAUVITHERM is the only PE-Xa district heating pipe manufactured in the UK which saves an estimated 29% on Co2 emissions annually.

RAUVITHERM is available in UNO 25-125mm and DUO 25-63mm.


  • Excellent flexibility due to corrugated outer jacket and closed cell PEX insulation
  • Long coils up to 330m possible which are 50% longer than similar flexible pipes
  • High insulating performance from closed cell cross-linked PE foam layers
  • Uses REHAU EVERLOCTM jointing technology
  • Shroud connections are highly insulated using PU foam
  • RAUVITHERM 125mm UNO can transport up to 1.7MW of heat at 80oC/50oC flow & return temperatures
  • WRAS certification for pre-insulated pipe and fittings
  • All sizes stocked in the UK with a full cutting service

PP-R district heating pipes

Due to the reduction in flow temperatures in new district heating networks, polymers are becoming increasingly accepted in place of traditional steel pipes. REHAU can now offer PP-R district heating pipes in 200-355mm (DN150-250) to be used on large district heating networks to complement their market-leading PE-Xa district heating pipes. PP-R pipes have been used across Europe for many years in district heating applications.


PP-R district heating pipes are joined via butt-welding technology, which is already commonly used in the gas and water sectors in the UK. Please note, installers will need to be become certified on a training course prior to any installations. 


What used to be only possible for cold water, gas and steel pipe heating systems is now available for hot water: NEXUS, the first hot tapping system for PE-Xa district heating pipes. Exclusively from REHAU.

  • World Exclusive - The first hot tapping fitting for PE-Xa heating pipes
  • Safety - Maximum safety thanks to unique silicone seal (TUV certified)
  • Cost Savings - Up to 50% cost savings for retrospective connections
  • Save time - Up to 80% time savings* during installation compared to conventional methods

*applies for d125, up to 50% at d63


UK Sales specialists

UK Technical & Design Services

UK Production

UK Stock

UK Product Range

Pre-insulated Butt Welding

What is District Heating?

Benefits of District Heating

Why Choose REHAU?

REHAU NEXUS hot tapping system

RAUVITHERM Shroud System

RAUTHERMEX Shroud System