Planning a bathroom renovation, updating your kitchen floors or undertaking a larger home retrofit?
Adding underfloor heating during a renovation is one of the most practical ways to bring lasting comfort into an existing Australian home.
Electric underfloor heating makes it possible to retrofit warmth into bathrooms, bedrooms, kitchens and living areas with minimal impact on floor height, while hydronic underfloor heating can be considered for larger renovations where floors are being rebuilt or built up.
This guide explains what homeowners, builders and trades need to consider, from floor finishes and waterproofing through to system choice, controls and installation timing, so you can get the right result before the new floor goes down.
Can You Retrofit Underfloor Heating into an Existing Home?
Yes. Underfloor heating can be retrofitted into many existing Australian homes, particularly when you are replacing tiles, carpet or timber flooring as part of a renovation.
You do not need to rebuild the entire house to enjoy warm floors. For most room-by-room renovations, electric underfloor heating is the most practical option. It is installed beneath the new floor finish and is especially well suited to bathrooms, ensuites, kitchens, laundries, bedrooms and living rooms.
Comfort Heat offers low-profile electric systems that can be installed within the tile adhesive layer, beneath floating timber or between carpet and underlay. For major renovations where floors are being removed and rebuilt, hydronic underfloor heating may also be an option for larger zones or whole-home comfort.
Comfort Heat tip: Ask about underfloor heating before new tiles, flooring, cabinetry and bathroom fixtures are ordered. Planning early gives you the greatest choice of systems and helps avoid avoidable changes to floor levels, door clearances or installation coordination.
When to Plan Underfloor Heating During a Renovation
The best time to add underfloor heating is when your existing flooring is already coming out, or when your new floor finish has not yet been installed.
This can include:
- Replacing bathroom or ensuite tiles
- Renovating a kitchen, laundry or mudroom
- Laying new tile or stone floors
- Installing floating timber flooring
- Re-carpeting bedrooms or living areas
- Adding a new extension
- Renovating a granny flat or secondary dwelling
- Rebuilding a ground-floor slab or screed
- Completing a major whole-home renovation
Heating is generally not an upgrade to leave until the end. The system needs to be installed beneath the finished floor, so it must be designed around the floor construction, permanent fixtures and heating zones.
For homeowners, thinking about underfloor heating early means you can make a considered comfort decision while the room is already under construction. For builders, early coordination prevents disruption later in the programme.
Comfort Heat’s promise is Invisible Luxury, Irresistible Comfort. In renovation terms, that means getting the detail beneath the floor right so the finished home feels better every day, without adding visual clutter or complexity.
We also provide a custom design layout for every job, regardless of project size or scope.
What Homeowners Need to Consider Before Retrofitting
When planning underfloor heating for a renovation, you do not need to become a heating expert. However, having the following information ready will help your Comfort Heat specialist recommend the right solution.
Which rooms are you renovating?
Bathroom underfloor heating is the most popular retrofit application in Australia, but it is not the only option.
Think about the rooms where warmth would make the biggest difference to daily life:
- Bathrooms and ensuites with cold tile floors
- Kitchens where your household spends long periods standing
- Bedrooms where cold floors make winter mornings harder
- Living spaces with tiled, stone or timber flooring
- Laundries, hallways and entryways
- Home offices, yoga rooms and wellness spaces
- New extensions or converted garages
- A bathroom may be the natural first project, but a larger renovation can be designed in zones so you can heat specific rooms independently.
What floor finish are you using?
Your floor covering is one of the most important factors in choosing a retrofit underfloor heating system.
| Floor finish | Suitable retrofit approach | Key consideration |
|---|---|---|
| Ceramic or porcelain tiles | Electric Thin Heating Mat or Screed Cable | Low-profile system within tile adhesive |
| Natural stone | Electric Thin Heating Mat or Screed Cable | Excellent heat conduction and retained warmth |
| Tiles with new screed | Electric Screed Cable | Requires sufficient screed depth in the floor build-up |
| Floating timber | Under Timber Electric Mat | Flooring must be approved for underfloor heating |
| Carpet | Carpet Heating Mat | Installed between the underlay and carpet |
| Large new renovation area | Hydronic Screed or Slab System | Best planned before screed or slab construction |
Tile and stone are highly effective finishes for underfloor heating because they conduct warmth well. Thin mats are commonly selected where no screed is being laid and floor height is limited.
Comfort Heat also offers purpose-designed systems for floating timber and carpet, helping homeowners extend radiant warmth beyond traditional tiled bathrooms.
How much floor height is available?
Floor height is one of the biggest technical considerations in a renovation.
Door thresholds, bathroom falls, floor wastes, adjoining floor levels and joinery all need to be considered before the system is selected. This is especially important in a bathroom retrofit, where even a few millimeters can affect drainage and transitions to adjacent rooms.
Comfort Heat Thin Heating Mats are approximately 3 mm high and sit within the tile adhesive or a thin levelling layer. This typically creates a total build-up of around 6 mm, depending on the substrate, adhesive and finish.
Where a new screed is being installed, electric screed cable may be more suitable. That system is embedded in a sand and cement screed and requires a larger floor build-up, which makes it best for projects where the construction allows for it.
How do you use each room?
The right system is also shaped by how and when a room is used.
A bathroom often benefits from a programmed schedule that warms the floor before the household wakes. A guest ensuite may only need heating when visitors are staying. Bedrooms can be independently controlled for a comfortable morning routine, while kitchen and living areas may require a different heating schedule.
Comfort Heat’s thermostat range includes straightforward controls, Wi-Fi programmable options and home automation-compatible thermostats. This allows homeowners to zone their heating and use warmth where it is needed, rather than heating every room the same way.
What Builders and Trades Need to Plan For
For builders and trades, retrofit underfloor heating is most successful when it is included in the early coordination process.
The system itself is designed to be straightforward, but it needs to work with waterproofing, tiling, electrical rough-in, floor finishes and the wider construction programme.
Confirm the floor build-up
Before installation, establish:
- The existing subfloor type, such as concrete slab, compressed sheet or timber
- The proposed finished floor material and thickness
- Whether a screed or levelling compound is planned
- Required door clearances and room-to-room transitions
- Bathroom floor falls and waste locations
- Fixed cabinetry, vanities, baths and appliances
- Expansion joints and construction joints where relevant
- Thermostat and electrical connection locations
Underfloor heating is generally designed around permanent fixtures and joinery. It is not usually installed beneath built-in cabinetry, baths or other fixed elements because those areas do not contribute meaningfully to room comfort and may restrict heat dissipation.
A Comfort Heat custom design layout provides a clear reference for builders, electricians, water proofers and flooring installers. It supports cleaner coordination and helps reduce uncertainty on site.
Coordinate trades for your renovation
Bathroom renovations require careful sequencing.
- A licensed electrician installs the required power supply and conduits within the wall.
- A waterproofing system is applied to the sub-floor.
- The heating cable is laid onto the waterproofed surface using methods that avoid penetrating the waterproofing membrane.
- A screed bed is laid over the cable and levelled to an even finish.
- A second layer of waterproofing is applied over the screed.
- The tiler can now complete the tiled floor installation.
- The licensed electrician completes the thermostat electrical connection.
Every bathroom is different, so the precise construction sequence should be agreed by the builder, waterproofer, tiler, electrician and heating supplier before work starts. This is particularly important where floor falls, drainage and compliance requirements are involved.
Plan the electrical works early
Electric underfloor heating must be connected by a licensed electrician.
The electrician will generally need to:
- Install the electrical supply in the walls
- Run conduit to the floor
- Connect and test the heating system
- Install the thermostat
- Complete commissioning and compliance work
Comfort Heat provides product information, loading details and installation guidance to support the electrician and flooring contractor through the process.
For owner-builders and experienced trades, Comfort Heat also offers custom-designed DIY electric kits, including a personalised installation diagram and technical support. Electrical connection work must still be completed by a licensed electrician.
Which Underfloor Heating System Suits a Renovation?
The best underfloor heating system for a renovation depends on the scope of work, the floor construction and the size of the area being heated.
| Renovation scenario | Best-fit system | Why it works |
|---|---|---|
| Bathroom or living areas with new screed | Electric Screed Cable | Flexible cable layout suitable for small to large areas |
| Tiling on top of tiles | Thin Mat System | Low floor build-up and responsive warmth close to the tile surface |
| Kitchen or extension with limited floor height | Thin Mat System | Low floor build-up and responsive warmth close to the tile surface |
| Bedroom or living area with new carpet | Carpet Heating Mat | Sits discreetly between carpet and underlay |
| Floating timber floor renovation | Under Timber Electric Mat | Designed specifically for floating timber applications |
| Major renovation with large areas being rebuilt | Hydronic Slab or Screed Heating | Ideal for a whole-home or multi-room radiant heating strategy |
| New concrete slab within an extension | Electric or Hydronic Slab Heating | Incorporated into the slab before it is poured |
Electric systems are generally the best fit for room-by-room renovation and retrofit projects. Hydronic systems are often most appropriate for extensive renovations and new builds where the floor structure is being rebuilt and whole-home heating is part of the brief.
Bathroom Underfloor Heating Renovation and Retrofit
A bathroom is one of the most rewarding rooms to add underfloor heating to during a renovation.
It is often the first space you enter in the morning and the last one you use at night. It is also likely to have tiled floors, high moisture levels and limited wall space for conventional heating.
Electric thin mat underfloor heating is a popular solution for bathroom renovations because it provides warm tiles without requiring major changes to the room layout. It is installed close to the finished tile surface and can be controlled with a thermostat and floor sensor for comfortable, consistent temperature management.
Bathroom renovation checklist
Before finalising your bathroom heating design, confirm:
- Are the existing tiles being removed, or tiled over?
- Will the bathroom be fully re-waterproofed?
- Is there enough clearance at the doorway for the floor build-up?
- Are the floor waste and required falls being changed?
- Will the tiles be laid directly on the subfloor or over a screed?
- Where will the thermostat be located?
- Where can the electrician run conduit and power?
- Which areas will be covered by fixed cabinetry, baths or vanities?
- Is a mirror demister worth including while the bathroom is open?
A Comfort Heat mirror demister mat is installed behind the bathroom mirror and gently warms its surface to help prevent fogging after showers. It is a small addition, but it supports the same design philosophy as underfloor heating: practical comfort that works quietly in the background.
Retrofitting Underfloor Heating in Other Rooms
Kitchen renovations
Kitchens are high-use spaces where people spend long periods standing, cooking and gathering. If you are replacing tiled, stone or other hard flooring, underfloor heating can create a noticeably more comfortable room without using valuable wall space.
Thin mats can suit tiled kitchen renovations where floor height is tight. Screed cable may suit a larger kitchen or extension where a new screed is part of the floor build-up. The custom heating layout should allow for islands, fixed cabinetry, appliances and other permanent fixtures.
Bedrooms and carpeted living rooms
If you are re-carpeting a bedroom or lounge room, underfloor heating can be incorporated at the same time.
Comfort Heat Carpet Heating Mats are positioned between the underlay and carpet. They are designed to remain undetectable underfoot, while delivering gentle radiant warmth through the carpeted space.
For floating timber flooring, Comfort Heat’s Under Timber Mats are engineered for timber floors and are designed to operate within the temperature tolerances of the material. Always confirm that your selected flooring product is approved by its manufacturer for use with underfloor heating.
Extensions and larger home retrofits
An extension is an opportunity to make a broader comfort decision.
If you are adding a new kitchen, open-plan living room, main bedroom suite or backyard pavilion, underfloor heating can be designed from the beginning of the construction programme. The scale of the extension, type of floor construction and desired heating coverage will determine whether electric or hydronic heating is the better solution.
For larger whole-home renovations, hydronic underfloor heating may be paired with an Intaflo air-to-water heat pump. The system circulates warm water through pipes beneath the floor and is designed for continuous, even radiant heat across larger areas.
Intaflo heat pumps are available from 9 kW to 30 kW, include Wi-Fi control and are compatible with solar power systems.
Can You Install Underfloor Heating Over Existing Tiles?
Yes!
Electric thin heating mats can be installed over existing tiles when the existing surface is sound, properly prepared and primed. The system is laid beneath the new floor finish, usually within tile adhesive or levelling compound.
This can be an appealing approach where removing the existing tiles would be excessively disruptive or costly. However, it is not suitable for every renovation.
Before installing underfloor heating over old tiles, consider:
- Are the existing tiles firmly bonded and free from movement?
- Will the additional floor height affect doors or thresholds?
- Will bathroom drainage and floor falls still work correctly?
- Does the renovation require new waterproofing?
- Is the substrate suitable for the new tile installation?
- Has the tiler approved the full proposed floor build-up?
A discussion between the builder, tiler, heating specialist and homeowner is essential before choosing this approach.
Electric vs Hydronic Underfloor Heating for Renovations
Both electric and hydronic underfloor heating provide radiant warmth from the floor up. The difference is primarily in their ideal project type, installation method and scale.
| Consideration | Electric underfloor heating | Hydronic underfloor heating |
|---|---|---|
| Best for | Bathrooms, kitchens, bedrooms, apartments and targeted room renovations | Major renovations, full homes and larger heated areas |
| System type | Heating cables or mats beneath the finished floor | Warm water through pipes beneath the floor |
| Typical renovation impact | Lower, especially with low-profile thin mats | Higher due to pipework, manifold and heat-source requirements |
| Floor build-up | Minimal for thin mat installations | Usually greater, especially in screed or slab applications |
| Heat response | Often quicker in low-profile systems | Best for stable, longer-duration whole-home heating |
| Controls | Individual room thermostats, including Wi-Fi options | Zoned controls with heat pump or boiler system |
| Maintenance | Heating element has no moving parts, filters or fluids | Heat source and water circuit require periodic servicing |
| Best project stage | Existing-home renovation or retrofit | Major renovation or new build |
For individual rooms being renovated, electric underfloor heating is usually the most practical and cost-effective starting point. Thin mats can be installed with minimal change to the existing floor height, and room-by-room controls help homeowners heat only the spaces they use.
For major renovations involving larger floor areas, new screeds or slabs, hydronic underfloor heating may be the better long-term choice. Comfort Heat’s hydronic systems can be paired with the Intaflo heat pump, offering a fully electric whole-home solution that can also work with rooftop solar.
Why a Custom Design Layout Matters
Every renovation has different constraints.
A small ensuite has different requirements from a large kitchen extension. A floating timber bedroom floor differs from a tiled bathroom floor. A heritage renovation may have limited floor height, while a new rear extension may allow for a complete screed or slab system.
That is why custom design matters.
Comfort Heat is the only heating company in Australia that provides a custom design layout for every project, regardless of size or complexity. The layout is designed around your specific room dimensions, permanent fixtures, floor finish, heating zones and installation conditions.
This helps ensure the heating system does what it should: provides effective, even warmth in the areas you use, while remaining completely unseen.
Comfort Heat has been Australian-owned and operated for more than 25 years, with a complete service that covers design, supply, installation and ongoing support. The team brings 75 years of combined engineering and installation experience to each project, and the approach remains simple: if underfloor heating is not the right solution for your renovation, Comfort Heat will tell you.
That is comfort you can trust, designed to feel effortless for years to come.
Ready to Plan Your Renovation?
A renovation is the ideal time to create the comfort you will feel for decades. Before you lock in your tiles, timber, carpet or bathroom layout, explore the right system for your project with the Comfort Heat Product Finder or speak with a Comfort Heat specialist.
Comfort Heat delivers complete electric and hydronic underfloor heating solutions, from custom design and supply through to installation support and ongoing care. It is Invisible Luxury, Irresistible Comfort, designed around the way you live.
The team here at Comfort Heat has over 25 years of experience and will always a custom design layout that assesses whether your existing floor structure is suitable. Contact the team to discuss your specific renovation.