In this four-part series, PHPI and Grant UK team up to bring you a whole house renewable heating project, from start to finish. In part three we take a step-by-step look at the installation of the home’s underfloor heating system.

In the summer of 2020, a large renovation project started at a family home in Chippenham, Wiltshire. It included the removal of the old heating system and an upgrade to a greener, renewable Grant UK heating system. A new heat source was installed alongside a new hot water storage cylinder, with underfloor heating systems laid throughout the downstairs of the property.

Underfloor heating is a popular choice for heat pump systems such as the Grant Aerona³ heat pump, which has been fitted into this house. It is especially effective in new build projects and extensions where this type of heat emitter is smoothly integrated into the initial designs, during the project’s in-depth planning stages.

Underfloor options
For the Grant House, two types of underfloor heating systems were fitted. Within the new extension, a Grant Uflex underfloor heating system was installed which was embedded within the floor construction. Throughout the remainder of the downstairs (where existing flooring was in place) the company’s low-profile underflooring heating system, Uflex MINI, was installed. This system is made up of self-adhesive panels with castellations and is just 15mm in finished floor height, which made it ideal for installation in the existing, level floors.

We followed Meadows Plumbing & Heating as the team worked on the downstairs of the new extension.

Matt prepared the floor with a damp proof membrane and laid 75mm thick Polyurethane insulation on top

Next, he fitted the edge insulation around the walls and a polythene membrane was then put on top of the insulation

Matt installed the underfloor manifold with mixing valve and pump

Jake started clipping the pipe into the insulation from the outside edge using a Uflex tacker clip stapler

The pipe was laid in a meander configuration with the flow heading towards the coldest areas first

Matt connected the pipe loops to the Manifold. The actuator wiring was connected to system controller

After filling and pressure testing the pipe loops, a dry screed was delivered and poured on top of the Uflex pipes

The screed was flattened to a 65mm thickness and then left to dry for around two months before it was tiled

Grant Uflex
Uflex underfloor heating systems effectively maintain room temperatures while also helping a heat pump to work as efficiently as it can. Grant Uflex is ideal for new builds and extensions because the pipe can be laid and screed poured during the early phases, allowing other works to be completed while the screed fully dries.

The Uflex MINI is for existing floors – its low profile means it needs less screed and therefore less drying time. In this house renovation, the Uflex MINI system was being walked on within three days, reducing disruption, and allowing the other stages of the project to continue.

About the house
The Grant House is a four-bedroom semi-detached property in Wiltshire which is undergoing a complete heating system upgrade as part of a wider renovation project. In addition to building a large extension off the side of the property, the owners are upgrading their home’s heating system, changing from a gas boiler to a renewable system thanks to the installation of a Grant Aerona³ air source heat pump.

To find out more, click here

About Grant UK
Grant UK has been designing and manufacturing reliable and easy to install heating products for over four decades. It’s product portfolio includes award winning Vortex oil fired condensing boilers and the latest renewable technologies like solar thermal, air source heat pumps, cylinders and condensing biomass (wood pellet) boilers, and an oil boiler/air source heat pump hybrid. The company also has a growing range of heat emitters from wet underfloor heating systems through to fan convectors and aluminium radiators.

Coming up in Part Four
We follow the step-by-step installation of the Grant Aerona³ air source heat pump and the handover of the heating system.

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