Hydronic Underfloor Heating for Existing Homes

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Hydronic Underfloor Heating for Existing Homes


There are a number of questions to go through when considering the installation of hydronic underfloor heating for an existing home.

Is your floor built on a foundation of a concrete slab or timber joists?

Depending on the answer, this will affect the change in floor height and associated costs. For an existing slab, of course all existing flooring would need to come off. We would then recommend an insulation to be laid, pipe will go on the insulation and a screed would be poured over the insulation. The total height addition to an existing floor would be approximately 85mm.

Image below is a demo of an underfloor heating system on an existing slab

Whilst for a timber joist floor structure, there would be a minor 2mm change in floor height as we would typically work by installing diffusion aluminium plates between the joists with suitable insulation under the plates. The aluminium plates would sit flush to the new floor boards or chipboard to go above the plates.

Hydronic underfloor heating for existing homes in sydney, melbourne, perth, australia

Will your floor allow for an increase in height?

This is an important consideration for homes with existing slabs. There are a number of changes that occur when altering floor heights, this involves considerations where there are existing cupboards, doors and between doorways. A change in floor height will also affect ceiling heights.

What is the most cost effective solution for an existing home?

9 times out of 10, a hydronic radiator panel install is cheaper for an existing home. For a home on a joist construction, the investment in an underfloor heating system with beautiful engineered oak may be more attractive.

The radiant panel system does not provide the same radiant heat output as an hydronic underfloor heating system, however this may not be mandatory for all. Typically we would install a new multipurpose gas condensing boiler or one of our high efficiency heat pumps combined with a buffer tank to service the radiator panels. Typical panel sizes vary depending on the size of room that requires heating, some installers work off rule-of-thumbs – but why do that when it can be done right with 5 minutes of thought?

How can you bring down the cost of a hydronic underfloor heating installation?

There are a few ways you can bring down the cost, this can include the removal of floorboards, nails and all chipboards. Cleaning of any glue residue on the joists or concrete flooring and providing a clean and debris free work surface whether that be on the concrete flooring or with the timber joists.

We would recommend to allow one of our qualified installers to install the hydraulic pipeworks, Liquid Transition do not certify installations completed by others due to the implied risks of incorrectly installed pipework.

I just want to take the chill off

We all do. There’s a reason why it gets chilly in an Aussie home and that is due to the high “heat load” of Australian homes. The heat load is the amount of heat a house requires to bring the room temperature up to a certain degree, typically for hydronic heating that is 20 or 21deg C.

So, to take the chill off – why do we need to size the radiator panels or the underfloor heating?

The reason we design each and every system has a duty to provide a certain amount of heat. Our customers want to maintain the room at a comfortable 20degC, that doesn’t the underfloor heating is always running! It simply means, the system turns on when the room temperature drops, this literally takes the chill off the room.

We combine a thermal storage tank with high efficiency heat pumps and sometimes Geothermal Pipework to an water-to-water heat pump or air-to-water heat pump. These systems provide high efficiency outputs for the homeowner with the beauty of the main system lasting up to 20 years.

If you have any enquiries on this article or past articles, please feel free to drop an email to info@liquidtransition.com.au

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