Which is the best underfloor heating system for joisted floors?

Wet underfloor heating systems are an effective way of incorporating a heating system into a joisted floor construction, for both new build and refurbishment situations. By utilising the space in the joist void with effective insulation, underfloor heating maximises heat output and allows an even distribution of heat across the entire floor space.


Joists are most commonly part of a suspended timber floor construction and help to support the subfloor which is installed on top. They provide the structural diaphragm, running over the entire floor area. Joisted floors are used typically on upper floors, where there is not a cast/concrete construction.



At Ambiente UFH we have a number of efficient wet underfloor heating systems that are suitable for joisted floor constructions, which are detailed below.



diagram of underfloor heating system for joisted floor

Specially designed for joisted floor systems, the AmbiPlate 30 underfloor heating system consists of diffuser plates fixed to the top side of the joists, spanning a joist void. Insulation must be installed tight up to the underside of the plates to ensure minimal downward heat loss and maximum upward heat output. Due to the reflective surface of the diffuser plates the heating ‘behaviour’ is quick to respond and even across the floor area.

With the AmbiPlate 30 system, there is no impact on the floor build up height to existing design, causing minimal disturbance especially on refurbishment projects.

Find out more about AmbiPlate 30



underfloor heating system for joisted floors diagram

The AmbiFloat 30 system is very similar to the AmbiPlate 30 system, but essentially it incorporates the insulation and diffuser plate into one product – a grooved and foiled insulation board. The AmbiFloat board is supported on either side of the joist with a batten and is installed tight up to the underside of the structural deck above it. Due to the reflective surface of the diffuser plates the heating ‘behaviour’ is quick to respond evenly across the entire floor area.

Find out more about AmbiFloat 30



Joisted floor underfloor heating system diagram

This system is a unique combination of a structural floor solution while incorporating underfloor heating. It consists of high grade 22mm moisture-resistant chipboard panels, incorporating 12mm underfloor heating pipework routed into the board. The tail/transit pipework often is run beneath the floor in the joist void, to minimise the need for any further routing of the boards. A plywood layer is then boned or fixed over the AmbiChipboard system and any floor finish can be laid over the top.

Find out more about AmbiChipboard



diagram of joisted floor underfloor heating system

The AmbiSolo system is designed for refurbishment projects where floor build up is at a premium. It incorporates a 12mm Ambiente underfloor heating pipe within a plastic castellated panel, which is then covered with 20mm of reinforced levelling compound. The AmbiSolo provides impressive response times, heating up in just 15-30 minutes (depending on floor covering) giving it a similar response time to a radiator. When using the AmbiSolo system over a chipboard deck on a joisted floor it is important that the area is sufficiently ‘tanked’ to save the levelling latex running through any gaps.

Find out more about AmbiSolo



When incorporated into a joisted floor construction, wet underfloor heating is an extremely efficient heating solution. Providing an even distribution of heat across both small and large areas, these solutions from Ambiente are ideally suited to new build and refurb projects.

Underfloor heating is a more efficient method of heating than radiators, working on the principle of radiation rather than convection. Also, due to the much larger heating surface area that UFH provides, it can operate on much lower flow temperatures than traditional systems, meaning it can be coupled with energy-efficient heat sources such as heatpumps and solar thermal systems. As underfloor heating is completely concealed within the floor, it allows you complete freedom of interior design and eliminates any safety risks associated with radiators on the walls.


If you would like more advice on which underfloor heating system to choose, get in touch with Ambiente today.

Did you find this article useful? Check out these posts on your UFH insulation options and things to consider when installing retro-fit underfloor heating.


This article was written by Robert Tuffin.
Robert is the Business Development Manager at Ambiente Systems UK with over 5 years experience working in the underfloor heating industry.